Assessment of the radiological exposure
pathways at Rum Jungle Creek South (Rum
Jungle Lake Reserve) - Batchelor
Report prepared for:
Northern Territory Government Department of Resources
May 2012
Report prepared by:
Department of Sustainability, Environment, Water, Population and
Communities
The Environmental Research Institute of the Supervising Scientist
ABN: 34 190 894 983
Report prepared by: A Bollhöfer, C Doering, G Fox, J Pfitzner, P Medley, Environmental
Research Institute of the Supervising Scientist (eriss), Darwin, NT
Reviewed and edited by: Dr D Jones
Contents
List of Figures
ii
List of Tables
iii
Executive summary
vii
1 Introduction
1
1.1 Background
1
1.2 Objective
2
1.3 Scope
2
2 Exposure Pathways
2
2.1 Uranium decay series
2
2.2 External gamma radiation
3
2.3 Inhalation of radon decay products
4
2.4 Inhalation of dust-bound long-lived alpha activity radionuclides
4
2.5 Ingestion of radionuclides in water
4
2.6 Ingestion of radionuclides in bushfoods
5
3 Methods
5
3.1 Site division
5
3.2 External gamma
7
3.3 Radon exhalation flux density
7
3.4 Radon concentration in air
7
3.5 Radon decay product concentration in air
8
3.6 Radionuclides in dust
9
3.7 Bushfoods
10
3.8 Soils
11
3.9 Water
11
4 Results
12
4.1 External gamma dose rates
12
4.2 Soil radionuclide activity concentrations
16
4.3 Radon and radon decay products
18
4.4 Dust-bound LLAA radionuclide concentrations
25
4.5 Radionuclide and metal concentrations in water and bushfoods
27
5 Dose assessment
40
5.1 The concept of Representative Person
40
5.2 Site occupancy scenarios
41
5.3 Dose rates from external gamma radiation
43
5.4 Inhalation doses from time spent on site
43
5.5 Ingestion doses from consumed quantities of water and bushfoods
47
5.6 Dose summary
54
5.7 Radiation protection context
61
Conclusions and Recommendations
62
References
64
i
Appendix A Gamma survey instruments and calibration
68
Appendix B Dust-bound LLAA radionuclide sampling periods and
results
70
Appendix C Details of water samples
71
Appendix D Gamma survey results
72
Appendix E Soil radionuclide activity concentrations and associated
gamma dose rates at selected points
92
Appendix F Radon exhalation flux density measurements
93
Appendix G Results of diurnal radon activity concentration
measurements at RJCS, 7–9 September 2011
95
Appendix H Results of diurnal radon decay product potential alpha
energy concentration measurements
96
Appendix I Airborne radon activity concentrations
100
Appendix J Photos of sampled fruit
102
List of Figures
Figure 1 Uranium decay series .................................................................................................. 3
Figure 2 Results of the 1999 airborne gamma survey flown in the greater Rum Jungle region
plotted as uranium to thorium ratios (NTGS 2011)................................................................... 3
Figure 3 RJCS site showing the different identified areas (domains), the lake and selected comeasurement points within these domains. ............................................................................... 6
Figure 4 TED attached to plastic star picket.............................................................................. 8
Figure 5 TEDs installed in existing vegetation ......................................................................... 8
Figure 6 Google Earth image showing the approximate locations of the dust sampling sites .. 9
Figure 7 Results of external gamma dose rate measurements at RJCS ................................... 14
Figure 8 Gamma dose rate contour lines at RJCS ................................................................... 15
Figure 9 Soil 226Ra activity concentration plotted versus external gamma dose rates ............. 16
Figure 10 Soil 226Ra activity concentrations at RJCS .............................................................. 17
Figure 11 Radon exhalation flux densities at the 29 selected points at RJCS ......................... 19
Figure 12 Radon exhalation flux density plotted against soil 226Ra activity concentration ..... 20
Figure 13 Diurnal variation of the PAEC of RDP in air at RJCS during the dry season and wet
season and at BBFC during the dry season ............................................................................. 21
Figure 14 Diurnal dry season variation of the radon concentration and calculated radon EEC
(top) and the equilibrium factor (bottom) at RJCS .................................................................. 22
Figure 15 Ratio of the PAEC of RDP in air at RJCS to that at BBFC .................................... 23
Figure 16 Two-monthly average radon in air concentrations measured at RJCS ................... 25
Figure 17 Timeseries of LLAA radionuclide concentrations in dust samples collected at RJCS
lake, at the site 3 km downwind of the burnoff of gamba grass and at BBFC ........................ 26
Figure 18 Water and bushfood sampling locations at RJCS ................................................... 27
Figure 19 Time series of total 226Ra activity concentration, selected metal and SO4
concentrations and [Mg+Ca]mol:[SO4]mol in Meneling Creek .............................................. 31
Figure 20 Time series of total 226Ra activity concentration and selected metal and SO4
concentrations for RJCS lake water ........................................................................................ 32
Figure 21 Decay corrected 226Ra, 228Ra, 228Th and 210Pb activity concentrations in mussel flesh
plotted versus mussel age ........................................................................................................ 34
Figure 22 Selected metal concentrations in mussel flesh (dry weight) plotted against mussel
age. .......................................................................................................................................... 35
ii
Figure 23 Wet weight (kg per mussel) and 226Ra, 210Pb and 228Ra loads (Bq per mussel)
plotted versus mussel age. ....................................................................................................... 48
Figure 24 Age distribution of mussels collected in RJCS in December 2010 (red) and of shells
collected from the lake’s edge close to the picnic area (green) ............................................... 49
Figure 25 Daily doses to an adult and child received from terrestrial gamma, RDP and dust
inhalation pathways for short-term visits , long-term visits and background conditions. ....... 55
Figure 26 Daily doses received for short-term visits, long-term visits and typical background
conditions, and contribution from the different pathways. ...................................................... 56
Figure 27 Total annual radiation doses in mSv (including background) received by an adult
and 10 year old child from terrestrial gamma, RDP and dust inhalation pathways for shortterm visits (14 visits at 6 hours each), long-term visits (14 days camping on site) and for
background conditions at Batchelor. ....................................................................................... 57
Figure 28 Total annual radiation doses (including background) received for short-term visits,
long-term visits and typical background conditions, and contribution from the different
pathways. ................................................................................................................................. 58
Figure 29 Modelled ingestion doses received from the various bushfoods and radionuclides
for people camping, hunting and gathering on site for an adult and a child, respectively. ..... 59
Figure 30 Total annual radiation doses (including background) received by children and
instructors taking part in the BOEU programme. .................................................................... 60
Figure A1 Relationship between air kerma rate and count rate for instrument GM1,
determined from calibration against a caesium-137 source of known activity ....................... 68
Figure A2 Relationship between measured counts for instruments GMB and GM1 .............. 69
Figure A3 Relationship between measured counts for instruments GM3 and GM1 ............... 69
Figure J1 Ficus racemosa (cluster fig)................................................................................... 102
Figure J2 Flueggea virosa (white currant) ............................................................................. 102
Figure J3 Passiflora foetida (passionfruit) ............................................................................. 103
Figure J4 Physalis minima (gooseberry) plant and fruit........................................................ 103
List of Tables
Table 1 Areal extents of areas 1–6 and average external gamma dose rates (including cosmic
component) measured at RJCS ................................................................................................ 13
Table 2 Average radon exhalation flux densities and radon exhalation fluxes ....................... 18
Table 3 Average equilibrium factor for various occupancy times and durations .................... 23
Table 4 Average dry season radon and RDP concentrations at RJCS on from 7 July to 9
September 2011. Post-rehabilitation RDP concentrations reported by Kvasnicka et al (1992)
are given for comparison. ........................................................................................................ 24
Table 5 Total water 226Ra and 210Po activity (at time of separation) concentrations and metal
and SO4 concentrations in RJCS water samples. ..................................................................... 30
Table 6 Radionuclide activity concentrations (Bq kg-1 dry weight) in mussel flesh from RJCS
lake determined via ICPMS, gamma spectrometry or alpha spectrometry. ............................ 33
Table 7 Metal concentrations (mg kg-1 dry weight) determined via ICPMS in flesh from
mussels from RJCS lake .......................................................................................................... 33
Table 8 Correlation matrix showing Pearson correlation coefficients (grey) and p-values for
the variables mussels age, selected metal concentrations and 226Ra, 228Ra, and 210Pb activity
concentrations.......................................................................................................................... 36
iii
Table 9 226Ra and 210Po activity concentration (dry weight) in fruits, yam and associated soils,
dry-to-wet sample mass ratio and 226Ra concentration ratio (CR) (fresh weight food item to
dry weight soil).. ...................................................................................................................... 38
Table 10 Metal concentrations (mg kg-1) in fruits and the yam collected from RJCS ............ 39
Table 11 Correlation matrix showing Pearson correlation coefficients (grey background) and
p-values for the variables 226Ra activity and selected metal concentrations in fruits and the
yam collected from RJCS. ....................................................................................................... 40
Table 12 Annual bushfood consumption (kg) for an Aboriginal adult living on the east branch
of the Finniss River and assumed 14 day bushfood consumption (kg) for an Aboriginal adult
at RJCS. A 10 year old child is assumed to eat half the amount eaten by an adult. ................ 42
Table 13 Effective terrestrial gamma dose rates (µSv h-1) received by an adult and 10 year old
child for various activities on the RJCS site ............................................................................ 43
Table 14 Inhalation dose coefficients for radon decay products (RDP) and long lived alpha
activity (LLAA) used in this assessment ................................................................................. 44
Table 15 Breathing rates (m3 h-1) for a representative adult and 10 year old child for different
physical activities .................................................................................................................... 44
Table 16 Fraction of the radon concentration relative to the 24 hour average for various
occupancy times and durations ................................................................................................ 45
Table 17 Average dose received (µSv h-1) from RDP inhalation from time spent at RJCS at
the combined picnic area + area 4 for various occupancy times and durations for short-term
visits ........................................................................................................................................ 45
Table 18 Average dose received (µSv h-1) from RDP inhalation from time spent at RJCS for
various occupancy times and durations for long-term visits ................................................... 45
Table 19 Average dose received (µSv h-1) from RDP inhalation from time spent at Batchelor
(BBFC) for various occupancy times and durations ............................................................... 46
Table 20 Doses received (×10-3 µSv h-1) by an adult and 10 year old child from the dust
inhalation pathway from time spent at RJCS and at Batchelor (BBFC) for different physical
activities................................................................................................................................... 46
Table 21 Ingestion dose coefficients (Sv Bq-1, from ICRP 1996) used in this assessment ..... 47
Table 22 Radionuclide activity concentrations (mBq l-1) in RJCS lake and Meneling Creek
water and doses received by an adult and 10 year old child per litre of water consumed ....... 47
Table 23 Radionuclide activity concentrations in mussel flesh from RJCS lake (Bq kg-1 wet
weight) and dose to an adult and 10 year old child from consumed quantities of mussel flesh
(µSv kg-1) ................................................................................................................................. 50
Table 24 Average radionuclide activity concentration in RJCS lake water (unfiltered) (mBq
l-1), concentration ratios (CR) for group 1 and group 2 fish, freshwater crocodile and turtle
from Martin et al (1995, 1998), calculated flesh radionuclide activity concentrations (Bq kg-1)
and dose received by an adult and child per kg of flesh consumed (µSv kg-1) ....................... 51
Table 25 Dose received by an adult and 10 year old child per kg of fruit consumed collected
from the picnic area and whole site ......................................................................................... 52
Table 26 Dose received by an adult and 10 year old child per kg of yam consumed collected
from the picnic area and whole site.. ....................................................................................... 52
Table 27 Wallaby: soil radionuclide activity concentrations, concentration ratios, animal
home range, calculated flesh activity concentration and doses received by an adult and 10
year old child per kg of flesh consumed from RJCS and environmental background areas ... 53
Table 28 Pig: soil radionuclide activity concentrations, concentration ratios, animal home
range, calculated flesh activity concentration and doses received by an adult and 10 year old
child per kg of flesh consumed from RJCS and environmental background areas ................. 54
Table 29 Daily doses (µSv day-1) received by an adult and 10 year old child from short- and
long-term visits to RJCS.......................................................................................................... 55
iv
Table A1 Meter and probe details of instruments used for external gamma radiation
measurements .......................................................................................................................... 68
Table B1 Dust sampling locations, periods between filter changes, sample volumes (m3) and
LLAA radionuclide concentrations (µBq m-3) ....................................................................... 70
Table C1 Sample number, collection dates and locations for the water samples .................... 71
Table D1 Results of gamma survey measurements, including spatial and date/time
information, measured and corrected counts per 60 seconds from each instrument and dose
rate. The cosmic component of external gamma radiation, estimated to be 0.066 µGy h-1 in
the Top End of the Northern Territory (Marten 1992b), has not been subtracted from the
results given in the table. ......................................................................................................... 72
Table E1 Results of soil radionuclide activity concentration (Bq kg-1) and external gamma
dose rate measurements (µGy h-1) at selected points at RJCS ............................................... 92
Table F1 Sampling locations and dates and radon exhalation flux densities (mBq m-2 s-1) .... 93
Table G1 Three-hourly data for airborne radon concentrations (Bq m-3) measured at RJCS. 95
Table H1 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at
RJCS, 13–14 January 2011...................................................................................................... 96
Table H2 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at
RJCS, 7–9 September 2011. .................................................................................................... 96
Table H3 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at
BBFC, 7–9 September 2011. ................................................................................................... 97
Table I1 Data for airborne radon concentrations (Bq m-3) ................................................... 100
v
vi
Executive summary
This report presents an assessment of doses to the public from radiological exposure pathways
at Rum Jungle Lake Reserve, a popular recreation area near the township of Batchelor that
lies on the footprint of the rehabilitated Rum Jungle Creek South (RJCS) uranium mine. The
assessment was considered necessary to provide the evidence base needed to determine
whether or not radiation risks to the public from current recreational uses of the site are
acceptable in the context of international recommendations for radiation protection. The
assessment forms part of the works conducted under the National Partnership Agreement on
the Management of the Former Rum Jungle Mine Site. The objectives of this agreement
funded by the Australian Government are to develop an improved understanding of the
current state of the environment at former uranium mine sites in the Rum Jungle area and to
identify if improved site management and rehabilitation strategies are needed.
Radiological conditions at Rum Jungle Lake Reserve, hereafter referred to as RJCS, were
determined through an extensive program of environmental sampling and measurement,
which included a site-wide gamma survey, measurement of radon and radon decay product
concentrations in air and analysis of radionuclides in bushfoods and water. Gamma radiation
levels and radon decay product concentrations on site are 6 and 4 times larger, respectively,
than typical background levels. Gamma radiation levels are generally similar to those from a
previous radiological assessment conducted by Kvasnicka et al (1992) after site rehabilitation
in 1990–91. The conclusion is that there has been no general deterioration in radiological
conditions at the site in the ~20 years since rehabilitation works were completed.
Legacy uranium mine sites, such as RJCS, are an example of an existing exposure situation,
which are exposure situations that already exist when a decision on control has to be taken.
For this type of situation the International Commission on Radiological Protection (ICRP)
recommends that source related reference dose levels, set typically in the range 1–20 mSv per
year, should be used to restrict individual dose, for example by removing contaminated
material and modifying exposure pathways, or by restricting access and thus reducing the
number of exposed people.
For people accessing the RJCS site for daytime only picnics and associated recreation
activities, external gamma radiation is the primary radiological exposure pathway and it
contributes an above background dose of only 0.0015 mSv per day (or 0.02 mSv per year if
the site was accessed 14 times per year for 6 hours in the afternoon). There is effectively no
above background contribution to afternoon dose from radon decay products due to the air
being well mixed during the day. The ingestion dose to people picnicking is considered to be
zero, as it was assumed that no bushfoods or water from the site are consumed in this
scenario. If water was ingested accidentally by a 10 year old child while swimming, ingestion
dose would be trivial and below 0.00005 mSv per ingested litre of water.
A case study for short term day access (9:00 am to 3:00 pm) by participants of the Batchelor
Outdoor Education Unit’s activities programme is included. Annual above background doses
to instructors (who access the site up to 40 times per year) and children (who access the site
once a year) are about 0.075 mSv and 0.002 mSv, which are equivalent to an increase
compared to typical background doses of only about 7% and 0.2%, respectively. Such a small
increase is well within the natural variability of background doses in the Top End.
For people accessing the site for occasional camping and food gathering activities, external
gamma radiation (~0.007 mSv per day), radon decay product inhalation (~0.012 mSv per day)
and bushfood ingestion (~0.03 mSv per day) are the most important radiological exposure
pathways. Average annual doses above background amount to 0.65 mSv, assuming that
people camp on site for a total of 14 days. For this scenario the conservative assumption has
vii
been made that the majority of food ingested is hunted (wallaby, pig and fish) and collected
(mussels, fruit and yams) on site, rather than reliance on shop bought food.
The total annual dose to a person that accesses the site for daytime visits only is not
appreciably different to the annual dose that would be received by a resident of Batchelor
from natural background radiation. The total annual dose to a person camping and consuming
bushfoods on site for 14 days is higher, but the above background contribution from time
spent on site is typically less than 1 mSv. This is below the general reference level band of 1–
20 mSv per year recommended by the ICRP for existing exposure situations. The implication
is that there is no unacceptable radiation risk to people accessing the site, both for daytime
picnics and for occasional camping and food gathering activities.
This assessment has been made assuming access of the site during the dry season, both for
short-term (picnics) and long-term (camping) visits. Doses received by the public during the
wet season are likely to be lower, primarily due to suppression of radon exhalation from the
ground surface and the lower wet season radon decay product concentration in air.
viii
1 Introduction
1.1 Background
1.1.1 Study context
The Environmental Research Institute of the Supervising Scientist (eriss) was commissioned
by the Northern Territory Department of Resources (DoR) to conduct an assessment of
radiological exposure pathways at Rum Jungle Lake Reserve, a popular recreation area near
the township of Batchelor. The reserve, referred to hereafter as Rum Jungle Creek South
(RJCS), lies on the footprint of a rehabilitated uranium mine. This assessment was initiated to
provide the evidence base needed to determine whether or not radiation risks to the public
accessing the site for recreational purposes are acceptable in the context of current
international recommendations for radiation protection of the public. The assessment forms
part of the works conducted under the National Partnership Agreement on the Management of
the Former Rum Jungle Mine Site to contribute to improved understanding of the current state
of environment at former uranium mine sites in the Rum Jungle area and to contribute to
improved site management and rehabilitation strategies. Other investigations and works
planned under the National Partnership Agreement are described in Fawcett & Rider (2011).
1.1.2 Location of Rum Jungle Creek South
RJCS is located approximately 100 km south (by road) of Darwin and 3.2 km west of
Batchelor. It is around 6.5 km south of the main Rum Jungle site. The proximity of RJCS to
local population centres means that it is accessible by a broad population demographic,
including both Aboriginal and non-Aboriginal people. It is a popular recreation resource for
local people and a stopping point for tourists travelling north to Darwin.
1.1.3 History of Rum Jungle Creek South
The RJCS ore body was discovered in late 1959 by ground follow-up of weak radiometric
anomalies detected by airborne gamma surveys flown in 1952, 1956 and 1957. The ore body
was the richest uranium reserve of all ore bodies mined in the Rum Jungle mineral field. Open
cut mining at RJCS produced approximately 2,000 tonnes of yellowcake (U 3O8) from around
650,000 tonnes of ore (AAEC 1963; Berkman 1968). The ore, mainly pitchblende (UO2), was
mined from April 1961 to August 1963. Between 1963 and 1970 initially below ore grade
material was stockpiled to the northwest of the pit. This material was subsequently
transported to the main Rum Jungle site for processing in 1969–71. When the Rum Jungle
uranium project ceased in 1971, the 66 m deep RJCS pit was allowed to fill with water to
produce an artificial lake. No additional efforts were made at the time to rehabilitate the site.
The site has since been used by the public for recreational activities such as for swimming,
picnics and camping. It was declared a Reserve in 1973 by the Minister of State for the
Northern Territory (Government Gazette 1973).
An assessment of radiological exposure pathways at RJCS in the mid 1980s (Kvasnicka 1986)
indicated that radiation risks to the public were potentially unacceptable in the context of
evolving radiation protection standards. A program of works to reduce radiological hazards
and rehabilitate the site was undertaken in 1990–91 (NTDME 1991). The rehabilitation works
included scraping of 100–400 mm of contaminated surface soil, replacing it with natural fill
material, and re-shaping and re-vegetating the overburden heap, including the installation of a
drainage system to facilitate rainwater runoff. Radiological conditions at RJCS generally
improved after rehabilitation (Kvasnicka et al 1992) and were considered appropriate for the
site to continue to be used as a public recreation area. However, the overburden heap
remained a source of higher external gamma radiation compared to adjacent areas, confirmed
1
by the results of an airborne gamma survey acquired by the Northern Territory Geological
Survey in 1999 (see section 2.2).
1.2 Objective
The objective of this assessment was to estimate doses to the public from radiological
exposure pathways at RJCS for current recreational uses of the site.
1.3 Scope
The assessment examines current radiological conditions at RJCS and doses to the public
from multiple exposure pathways for two occupancy scenarios:

Short-term visits for daytime picnics and swimming

Long-term visits for camping, swimming and food gathering activities
The exposure pathways included in the assessment are:

External gamma radiation

Inhalation of radon decay products (RDP)

Inhalation of long-lived alpha activity (LLAA) radionuclides in or on dust

Ingestion of radionuclides in water from RJCS lake and Meneling Creek

Ingestion of radionuclides in bushfoods sourced from the RJCS site
The findings of this assessment are compared with those from a previous radiological study
conducted in 1990-91 (Kvasnicka et al 1992). Dose estimates are then compared with current
recommendations of the International Commission on Radiological Protection (ICRP) (ICRP
2007) to provide the radiation protection context. This radiation protection context is
discussed in section 5.7 of this report. If applicable, strategies are provided to ensure that
exposure levels to members of the public are both acceptable and comply with appropriate
national and international guidelines.
2 Exposure Pathways
2.1 Uranium decay series
The history of the RJCS site suggests that the main radionuclides of concern for this
assessment are members of the uranium decay series. Figure 1 shows the uranium decay
series, including half-life and mode of decay (α or β) of each radionuclide.
2
Figure 1 Uranium decay series, showing the half-life and decay mode (α or β) of each radionuclide
2.2 External gamma radiation
The external exposure pathway at RJCS is from gamma radiation from radionuclides in soils,
rocks and mining residues. Ground-based gamma surveys by Kvasnicka et al (1992)
conducted after site remediation in 1990–91 and an aerial gamma survey of the main Rum
Jungle mine site and surrounds acquired by the Northern Territory Geological Survey in 1999
(NTGS 2011) indicate that the overburden heap has relatively higher uranium concentration,
as expressed by the higher uranium to thorium ratios shown in Figure 2, and is a source of
higher external gamma radiation compared to adjacent areas. While public access to the
overburden heap is generally hampered by dense vegetation cover and difficult terrain, it can
become more easily accessible following removal of the vegetation through controlled burn
offs which take place each dry season. There is also the possibility that rainwater runoff and
leaching of radionuclides from the overburden heap may increase external gamma radiation
levels and thus the dose to the public around the base of the heap and along drainage lines.
Rum Jungle
Rum Jungle Creek South
Figure 2 Results of the 1999 airborne gamma survey flown in the greater Rum Jungle region plotted as
uranium to thorium ratios (NTGS 2011). Uranium to thorium ratios are coloured, with the red colour
indicating relatively higher uranium concentrations compared to thorium. The location of the overburden
heap at RJCS is clearly visible
3
2.3 Inhalation of radon decay products
Radon-222 (radon) is a radioactive noble gas in the uranium decay series and the immediate
progeny of radium-226 (226Ra). Gaseous radon emanates from soil grains and rocks following
226
Ra decay. It then diffuses through the interstitial soil space and is exhaled from the ground
surface to the atmosphere where it is dispersed by diffusion and by wind currents. The radon
exhalation flux density from the ground surface depends on several factors, including soil
type (sandy, silty, etc), soil porosity, soil moisture content and soil uranium and radium
content (Porstendörfer 1994).
Radon decays with a half-life of approximately 3.8 days via a number of short-lived progeny
to lead-210 (210Pb) with a half-life of 22.3 years. Inhalation of radon gas itself does not
contribute much to dose since it is immediately exhaled. The main contribution to dose is
from the inhalation of RDP in air. Some of the inhaled RDP are retained in the soft tissue of
the lung, with the subsequent alpha decay delivering a radiation dose to the respiratory
system.
The potential alpha energy concentration (PAEC) is commonly used as a proxy for the
radiation dose that may be received from the inhalation of RDP. It provides a measure of the
energy originating from the alpha decays of RDP per unit volume in air. Kvasnicka et al
(1992) reported that the average PAEC of RDP in air at RJCS after site remediation in 1990–
91 was around two times higher than at Batchelor and that this finding was attributable to the
radiological characteristics of the RJCS site.
2.4 Inhalation of dust-bound long-lived alpha activity radionuclides
The inhalation of LLAA radionuclides contained in or on dust can contribute to the radiation
dose received by the public at or near a uranium mine site. If public access is restricted, then
the dust inhalation pathway from a rehabilitated site may be insignificant. However, the dust
inhalation pathway should be considered for activities conducted on or close to the site with
potential to generate dust (camping, traffic, etc), such is the case for recreational uses of the
RJCS site.
In addition, chemical elements, including uranium decay series radionuclides, are taken up
from the soil and transported into the above ground parts of the plants. Leaf litter on the RJCS
overburden heap may thus show elevated concentrations of radionuclides. The inhalation of
dusts and ash created by bushfires may increase the dose received by the public via the dust
inhalation pathway. Whereas rainfall and a dense vegetation cover decrease the potential of
dust generation, dry conditions and bushfires may increase the potential for windblown dust
and ash.
2.5 Ingestion of radionuclides in water
Kvasnicka (1986) estimated the dose per unit consumption of water from the RJCS Lake to be
1.5 × 10-4 mSv l-1 from measured concentrations of uranium decay series radionuclides. This
dose per unit consumption suggests that even in the extreme case of a person drinking two
litres of lake water each day for a full year, the resulting dose would only be around 0.1 mSv,
which is equivalent to 10% of the annual dose limit for a member of the public.
The current Australian Drinking Water Guidelines (NHMRC, NRMMC 2011) recommend a
screening level for radiological quality of drinking water of 0.5 Bq l-1 for both gross alpha and
gross beta activity. Radionuclide activity concentrations reported by Kvasnicka (1986) and
Kvasnicka et al (1992) indicate that the activity in RJCS lake water may have been above this
screening level. Whilst a re-assessment of the radiological quality of the water is warranted, it
4
is unlikely that annual doses to the public from the ingestion of water from the RJCS Lake
will be significant, as it is not used as a routine drinking water supply.
2.6 Ingestion of radionuclides in bushfoods
The accumulation of radionuclides in bushfoods and their consumption can be an important
exposure pathway for Aboriginal people leading a traditional or semi-traditional lifestyle, as
well as for non-Aboriginal people living off the land. In particular, the ingestion of 226Ra in
freshwater mussels can contribute considerably to the ingestion dose, depending on diet
composition (Martin et al 1998). The ingestion of natural-series radionuclides in other
bushfood items, including terrestrial fauna and flora, can also contribute to the dose received
via this pathway (Bollhöfer et al 2007; Ryan et al 2009).
Bushfoods common to RJCS include freshwater mussels and terrestrial fruits and vegetables,
including passionfruit and yam, which can be found growing at the site. Wallaby and wild pig
may traverse the site as part of their home range and may be harvested for sustenance by
Aboriginal and non-Aboriginal people living off the land.
The bushfood ingestion pathway was not included in the pre- and post-rehabilitation dose
assessments performed by Kvasnicka (1986) and Kvasnicka et al (1992).
3 Methods
3.1 Site division
Previous radiological assessments at RJCS by Kvasnicka (1986) and Kvasnicka et al (1992)
divided the site into seven ‘areas’ (domains) on the basis of measured radiation levels and
land use. The same approximate site division was used in the current assessment (Figure 3) to
enable comparison with results from previous studies. The seven areas were:

Area 1: Former stockpile area to the northwest of the lake

Area 2: Weir at southern edge of the lake

Area 3: Former mine office, workshop and machinery areas north of the lake

Area 4: Western bank of the lake

Area 5: Site access road

Area 6: Overburden heap to the west of the lake

The lake
The project proposal to NTG mentioned a disturbed area to the north of the lake where waste
rock was stored during operation of the mine. During fieldwork, this area could not be
identified or accessed due to relatively dense vegetation and rugged terrain. However, it is
very unlikely that this area to the north of the Lake is typically accessed by short or long term
visitors of the site. It has thus not been considered further in this assessment.
An additional domain – ‘picnic area’ – has been identified in this assessment. The picnic area
comprises the shady area around two sets of concrete picnic tables located adjacent to the lake
near the eastern corner of the overburden heap. Eriss believes this to be the most commonly
accessed area for recreational activities. This area also provides the easiest access to the water
via its gently sloping bank.
Twenty nine points from across the site were selected for parallel measurement of radon
concentration in air, radon exhalation flux density, external gamma radiation and soil
5
radionuclide activity concentration (Figure 3). The purpose of taking these parallel
measurements was to investigate relationships between any of these parameters.
Figure 3 RJCS site showing the different identified areas (domains), the lake and selected comeasurement points within these domains
6
3.2 External gamma
A gridded gamma survey of the RJCS site was conducted on 7–9 September 2011. The
resolution of the survey was approximately 20 m × 20 m on the overburden heap and 30 m ×
30 m across the rest of the site. Measurements were made of the total counts per 60 s at a
height of 1 m above the ground surface. Details of the instruments used and their calibration
are provided in Appendix A. The geospatial coordinates (easting and northing) of each
measurement point was determined by global positioning system (GPS).
Analogous measurement of external gamma radiation was made in the grounds of the
Batchelor Bushfire Council (BBFC) on 9 September 2011 in order to provide an offsite
(background) reference value.
3.3 Radon exhalation flux density
Charcoal-loaded canisters were used for radon exhalation measurements. The general
methods of sampling, radioactivity analysis and determination of radon exhalation flux
density were similar to those described in Bollhöfer et al (2006). Canisters were deployed in
the field on 7 July 2011 and recovered four days later on 11 July 2011. Canisters were
deployed in either duplicate or triplicate within an area of approximately 1 m2 at the 29
selected points. Three additional canisters were carried into the field but remained sealed at
all times. These canisters were controls, used to determine the background activity of the
charcoal in the canisters. Radioactivity analysis of field and control canisters was performed
at eriss laboratories on 12–13 July 2011.
3.4 Radon concentration in air
Track etch detectors (TEDs) supplied and analysed by Radiation Detection Systems in
Adelaide were used for measurement of average radon activity concentration in air. The
theory of radon measurements using TEDs is described in detail in Durrani and Ilić (1997).
TEDs were deployed at RJCS on 7 July 2011 and recovered approximately two months later
on 9 September 2011. Two TEDs were deployed at each of the 29 selected points at a height
of approximately 1.5 m above the ground surface, representing the breathing zone of a
standing adult. The TEDs were attached to either a plastic star picket (Figure 4) or tree branch
(Figure 5). Additional TEDs were deployed at the selected point within the picnic area: two at
a height of 20 cm above the ground surface, representing the breathing zone of a person lying;
two at a height of 75 cm above the ground surface, representing the breathing zone of a
person sitting; and four TEDs inside the Stevenson screen which was installed to house the
Environmental Radon Daughter Monitor (ERDM) during deployment on site. Two TEDs
were also deployed at BBFC for the same period to provide an offsite (background) radon
concentration in air value. Four TEDs additional to those deployed in the field were sealed in
an evacuated air tight container in the eriss laboratory for the duration of the field sampling.
These were controls, used to determine the pre- and post-deployment radon exposure of the
TEDs.
On the date of collection, the TEDs at point 10 could not be found. Some of the TEDs at other
points had dislodged and were found lying on the ground, including those deployed at 75 cm
height at the picnic area. This dislocation may have been caused by animal activity, such as
cattle grazing on the site. As radon concentration will be higher at the soil surface compared
to the free air, the results from these dislodged TEDs were not used for further interpretation.
Consequently, there are no radon data available for sampling points 10, 15, 16, 18 and 20.
7
In addition to the TED radon measurements, a RAD7 radon detector was used to make threehourly measurements of radon activity concentration in air at the RJCS site. These
measurements were made within the picnic area on 7–9 September 2011. The theory of radon
measurements using the RAD7 radon detector and its general method of operation are
described in Durridge (2011).
Figure 4 TED attached to plastic star picket
Figure 5 TEDs installed in existing vegetation
3.5 Radon decay product concentration in air
Environmental Radon Daughter Monitors (ERDM) from Radiation Detection Systems in
Adelaide were used to measure the PAEC of RDP in air. Dry season measurements were
made within the picnic area at RJCS and at BBFC on 7–9 September 2011. Wet season
8
measurements were made at RJCS on 13–14 January 2011. No offsite RDP measurements
were made in the wet season. The ERDMs operated at a nominal flow rate of 0.3 and 0.35 l
min-1, respectively, drawing air through a Whatman GF/C filter positioned above an alpha
counter. Hourly PAEC data was logged in the internal memory of the units and downloaded
at the eriss laboratories.
3.6 Radionuclides in dust
EcoTech MicroVol-1100 low flow rate samplers fitted with Whatman GF/C filters were used
for the collection of dust in air. Samplers were deployed at three locations (Figure 6): adjacent
to RJCS lake; offsite, approximately 3 km downwind (northwest) of the controlled burn off of
gamba grass that took place at RJCS on 30 June 2011 to determine if there was a noticeable
increase in dust-bound radionuclide concentration during the fire; and BBFC to provide an
offsite (background) reference value. Details of the sampling periods at each location are
provided in Appendix B. The sampler at RJCS Lake was moved approximately 100 m from
its original location on 7 September 2011 to position it within the picnic area adjacent to a
temporary (two day) camp established by the study team.
Filters were analysed for total alpha activity in eriss laboratories using Daybreak 582 alpha
counters. Count times were typically three to four days to ensure reasonable counting
statistics were achieved. Measurement of the background alpha activity of the counters was
made prior to analysis of each filter. The background count rate was subtracted from the filter
count rate to determine the net count rate, with a correction factor for counter efficiency
applied to determine the alpha activity on the filter.
Figure 6 Google Earth image showing the approximate locations of the dust sampling sites
9
3.7 Bushfoods
3.7.1 Fruits and yam
Fruits and yam were collected from the RJCS site over the duration of the project. Samples
were picked by hand and put into zip-lock plastic bags. Sampling locations and dates for the
fruit and yam samples collected are provided in Table 9 in section 4.5.3. After collection,
samples were oven dried at 60ºC for several weeks, then crushed to a fine powder using either
a mortar and pestle or a food processor.
Radionuclide activity concentrations (226Ra and 210Po) in these environmental samples were
measured via alpha spectrometry due to the much lower limit of detection compared to
gamma spectrometry. Artificial tracer isotopes (133Ba and 209Po) of known activity
concentrations were added to the samples before they were digested using concentrated nitric
and hydrochloric acids. The radionuclide of interest was separated from the sample matrix
using wet separation and ion exchange techniques. The activity concentration of the
respective radionuclide was then determined via alpha spectrometry. Further details of the
alpha spectrometry methods used are described in Martin and Hancock (2004) and Medley et
al (2005).
Uranium and other metal concentrations in the fruit and yam samples were measured via
ICPMS at the Northern Territory Environmental Laboratories (NTEL). The suite of analytes
were aluminium, calcium, magnesium, barium, strontium, potassium, iron, manganese,
cadmium, cobalt, copper, lead, zinc and uranium. Although out of scope of this assessment,
the measurement of these metals can give information on the uptake of elements essential for
plant growth (such as potassium, calcium, magnesium, iron or zinc), whereas others can give
information on the uptake of analogue elements for some radionuclides (strontium and barium
as an analogue for 226Ra, or stable lead as an analogue for 210Pb). The concentrations
measured have been included in this report for information purposes.
3.7.2 Mussels
During various trips to RJCS evidence of mussel consumption was found in the form of
mussel shells scattered around disused fire places. Mussels were visible along sandbanks in
the lake, but no mussels were found in Meneling Creek between the upstream and
downstream sites by the study team.
Mussels were collected by hand from the RJCS Lake on 7 December 2010, placed in plastic
buckets filled with lake water and transported back to the eriss laboratories for processing.
They were purged in 10–15 litres of lake water for 2–3 days to remove gut contents. An
aerator was placed in the bucket throughout the purging process and the water changed daily.
After purging, mussels were measured for length, width and total mass. They were dissected
to remove the flesh using stainless steel scalpel blades to minimise contamination of the
samples, following the methods of Allison and Simpson (1983), in a laminar flow cabinet
lined with a Teflon base. The flesh samples were oven dried at 60°C for several weeks and
reweighed to determine the dry weight, which was typically about 10% of the wet weight.
The age of each mussel was determined by placing the shell over an incandescent light source
and counting the annuli (Humphrey and Simpson, 1985). The dried and ground flesh of each
mussel was combined according to age class to provide a bulk sample for analysis. The
average length and dry weight per age class were determined from the individual
measurements described above.
A composite sample of each age class was cast in epoxy resin for determination of
radioisotopes of radium (226Ra and 228Ra), lead (210Pb) and thorium (228Th) by gamma
10
spectrometry. Mussels less than 1 year of age, or an age class with insufficient mass (< 2 g
dry weight) for analysis by gamma spectrometry, were analysed by alpha spectrometry for
226
Ra only. More detail on sample preparation and analysis is given in Bollhöfer et al (2011).
Details of the gamma spectrometry methods are described in Murray et al (1987), Marten
(1992a) and Esparon and Pfitzner (2009).
Mussel flesh was also sent to a commercial chemical analysis laboratory (Northern Territory
Environmental Laboratories, NTEL) to determine the concentrations of aluminium, barium,
calcium, copper, iron, magnesium, manganese, lead, rubidium, uranium and zinc via ICPMS.
Detailed descriptions of the methods for sample preparation and analysis via this technique
are given in Bollhöfer et al (2011) and Bollhöfer (2012).
3.7.3 Assumed diet
In 2006, some dietary information was gleaned by eriss staff through consultation with
Aboriginal people living about 25 km downstream of the main Rum Jungle site on the Finniss
River (Bollhöfer et al 2007). This consultation was part of a radiological assessment for the
main Rum Jungle site. Although it was originally proposed to consult with local people on
bushfood sources and dietary habits for this study, the dietary information obtained in 2006
was considered sufficient to conduct an ingestion dose assessment and no further consultation
was conducted. Bushfood consumption assumed in this assessment is likely to be an
overestimate as local people accessing RJCS have easy access to shop bought food & drink in
Batchelor. Consequently, it will result in a conservative estimate of ingestion doses.
3.8 Soils
A soil sample was taken with every fruit sample collected. This soil sample was a
combination of the top 1–10 cm of soil scraped from 4–5 sites at the base of the fruit bearing
tree or bush and put into zip-lock sample bags. For the yam sample, the soil surrounding the
yam was taken and put into a zip-locked bag.
Soils were also taken from the 29 selected points across the RJCS site. A soil sample was
collected at the precise location of each charcoal-loaded canister used for radon exhalation
measurements, after the canister was removed. A stainless steel corer with an internal
diameter of 47 mm and a length of 54 mm was hammered into the soil until the top of the
corer was level with the soil surface. Soil surrounding the corer was then carefully scraped
away so that the corer and the soil inside the corer could be removed intact. All of the soil
from the corer was then emptied into a clean plastic bag which was sealed and labelled.
Soils were oven dried at 100°C at eriss laboratories for 1–2 days. Soil samples were then
ground with an agate ring mill and a subsample of each was sent to an external laboratory
(NTEL) for ICPMS analysis to determine uranium concentrations. The remainder of the
sample was prepared for gamma spectrometry analysis for determination of radioisotopes of
radium (226Ra and 228Ra), lead (210Pb), thorium (228Th) and potassium (40K).
3.9 Water
Surface water samples from RJCS Lake and Meneling Creek were collected in acid-washed
plastic bottles at several times through the duration of the project. The Meneling Creek water
samples were collected at points upstream, midstream and downstream of the overburden
heap. Appendix C provides collection details, including locations and dates, for each water
sample collected.
A portion of the water sample was filtered at the eriss laboratories using a 0.45 µm filter
within 24 hours of collection. Both the unfiltered and filtered fractions were then acidified to
11
~1% HNO3 (AnalR) and subsamples of each sent for ICPMS analysis to determine uranium
and metal concentrations. For the first group of samples, collected on 25 October 2010,
results were only available for the filtered and residue fraction as the entire sample was
filtered, but no analysis was performed on the unfiltered sample. Due to the high background
for some trace metals in the digested filter paper, only filtered water metal concentrations
were reliable for some of the metals from the first round of sampling.
Both the filtrate and unfiltered sample were analysed for 226Ra and 210Po by alpha
spectrometry and via ICPMS for aluminium, calcium, magnesium, barium, rubidium,
sulphate, iron, manganese, copper, lead, zinc and uranium. Limits of reporting for metal
analyses were 0.1 mg l-1 for calcium, magnesium and sulphate, 20 µg l-1 for iron, 0.1 µg l-1 for
zinc, 0.01 µg l-1 for manganese, rubidium, copper and lead and 0.001 µg l-1 for uranium. More
detail on sample preparation and ICPMS analysis is given in Bollhöfer (2012). Results for
calcium, magnesium, sulphate and uranium concentrations are discussed. Other metal
concentrations have been included in this report for information purposes.
4 Results
4.1 External gamma dose rates
The results of individual external gamma radiation measurements are tabulated in
Appendix D. Figure 7 shows the location and approximate magnitude of the measurements
overlaid on an aerial photo of the RJCS site. The measurements include the contribution from
cosmic radiation, which has been estimated to be around 0.066 µGy hr-1 in the Top End of the
Northern Territory (Marten 1992b). Figure 8 shows a contour plot of the data. This contour
plot has been created using the ArcGIS geoprocessing tool, which interpolates a surface from
data points using an inverse distance weighted technique. The plot can be used to elicit
surface variations and directional trends from the underlying data.
The measurements shown in Figure 7 indicate that the overburden heap (area 6) is a source of
higher external gamma radiation compared to adjacent areas. The highest external gamma
dose rates at the site, up to 5.8 µGy h-1, were measured at the eastern corner of the overburden
heap. External gamma dose rates measured on the former stockpile area (area 1) were in the
range 0.2–0.5 µGy h-1. Typical background dose rates in the vicinity of RJCS after site
rehabilitation in 1990–91 were around 0.15 µGy h-1 (Kvasnicka et al 1992). The external
gamma dose rate measured at the BBFC as part of this study was 0.12 µGy h-1.
Table 1 gives the average external gamma dose rate measured for the terrestrial areas at RJCS
and for the site overall, both for this study and for those of Kvasnicka (1986) and Kvasnicka
et al (1992). In particular it provides for comparison the average values for the same areas
before and after site rehabilitation in 1990–91, and also gives the environmental background
gamma dose rate determined from measurements made at RJCS and BBFC in this study. The
average external gamma dose rates measured in this study are effectively the same as those
from the post-rehabilitation study by Kvasnicka et al (1992), taking the spread of the data into
account. The implication is that there has been no increase in the external gamma radiation
hazard at the site in the ~20 years since rehabilitation works were completed.
The contour plot shown in Figure 8 suggests that some radioactive material from the eastern
corner and the southeast edge of the overburden heap has been washed towards a tributary of
Meneling Creek. The implication is that some of the material has potentially entered
Meneling Creek itself, depositing downstream.
12
Table 1 Areal extents of areas 1–6 and average external gamma dose rates (including cosmic
component) measured at RJCS. N indicates the number of measurements made in this study. Postrehabilitation (Kvasnicka et al 1992) and pre-rehabilitation (Kvasnicka 1986) values are also given.
Area (ha)
N
Dose rate (µGy h-1)
Description
This study
2011
Kvasnicka et
al (1992)
Kvasnicka
(1986)
Area 1
7.2
91
Former stockpile
0.29 ± 0.09
0.24 ± 0.23
2.6
Area 2
1.6
37
South edge of lake
0.41 ± 0.18
0.23 ± 0.03
1.5
Area 3
2.5
32
North of lake
0.28 ± 0.07
0.19 ± 0.08
0.47
Area 4
1.3
25
West bank of lake
0.34 ± 0.16
0.16 ± 0.03
1.3
Area 5
1.7
21
Access road
0.31 ± 0.09
0.17 ± 0.03
1.4
Area 6
14.9
456
Overburden heap
1.00 ± 0.72
1.39 ± 1.36
6.5
Area 1–6
29.1
662
Areas 1–6 combined
0.79 ± 0.68
Picnic area
0.67
28
General picnic area
0.58 ± 0.43
Study area
37.1
850
Total area surveyed
0.75 ± 0.67
1
Environmental background
0.12 ± 0.02
BBFC
13
Figure 7 Results of external gamma dose rate measurements at RJCS
14
Figure 8 Gamma dose rate contour lines at RJCS, interpolated using the inverse distance weighted
(IDW) technique in ArcGIS
15
4.2 Soil radionuclide activity concentrations
The results of soil radionuclide activity concentration measurements are provided in
Appendix E. Figure 9 shows the relationship between 226Ra soil activity concentrations and
external gamma dose rates measured at the 29 selected points at RJCS. The slope of the linear
regression line of best fit (1530 Bq kg-1 per µGy h-1) can be used to estimate 226Ra soil activity
concentrations from the external gamma dose rate measurements. Figure 10 shows the
external gamma dose rate measurements converted to 226Ra soil activity concentrations using
this relationship.
The gamma signal in air at a height of 1 m above the ground generally comes from
radionuclides located in the top ~0.5 m of the soil, with deeper lying radionuclides only
contributing a few percent or less (depending on photon energy) to the signal (ICRU 1994).
For radionuclides in the uranium decay series, the majority of the terrestrial gamma signal
measured at 1 m height above ground originates from the decay of 214Bi, a radioactive decay
product of 226Ra. Consequently, in a uranium rich environment there should be a linear
relationship between soil 226Ra activity concentration and external gamma dose rates, as
shown by the data obtained for this study (Figure 9).
12000
Ra-226 = 1530*E+0.17
r ²= 0.93
Ra-226 [Bq/kg]
10000
8000
6000
4000
2000
0
0
1
2
3
4
5
6
E [µGy/hr]
Figure 9 Soil 226Ra activity concentration plotted versus external gamma dose rates
16
7
Figure 10 Soil 226Ra activity concentrations at RJCS calculated from external gamma dose rate
measurements using the relationship shown in Figure 9
17
4.3 Radon and radon decay products
The RDP inhalation pathway has been identified by Kvasnicka et al (1992) as the main
contributor to total doses received by the public at RJCS after site rehabilitation (although the
assessment did not include the ingestion pathway). Temporal and geographical airborne radon
and RDP concentration data were thus required to assess the present magnitude of the RDP
inhalation pathway at the site, two decades after rehabilitation.
The most important parameters for dose estimation due to inhalation of RDP are the PAEC
(Porstendörfer 1994) and the equilibrium factor, which gives a measure of the ratio of the
PAEC of RDP present in ambient air to the PAEC of RDP assumed in equilibrium with
radon. The unattached fraction of radon progeny also influences estimated doses from RDP
inhalation, but its determination was out of scope for this study.
Radon and RDP measurements were made at various locations to determine dry season spatial
and diurnal variations. An additional measurement of RDP was made during the wet season.
Radon and RDP were measured simultaneously in the dry season at the picnic area at RJCS to
enable determination of the equilibrium factor. In order to determine the radon exhalation
source term at the site, radon exhalation measurements were conducted with a focus on the
overburden heap, and results compared with the levels of 226Ra in soils. The determination of
radon exhalation rates for various areas allowed ranking the sources of radon in air at RJCS.
4.3.1 Geographic variability in radon exhalation
The results of individual radon exhalation flux density measurements are provided in
Appendix F. Figure 11 shows the magnitude of radon exhalation flux densities at the 29
selected points overlaid on an aerial photograph of the RJCS site. Magnitudes are given as the
arithmetic mean of the measurements from the two or three charcoal-loaded canisters
deployed at each selected point. The figure indicates that the highest radon exhalation flux
densities were measured at the southeast edge of the overburden heap (area 6), which
coincides with the area of highest external gamma dose rates (Figure 7) and soil 226Ra activity
concentrations (Figure 10). This area is not far from the picnic area.
Table 2 gives the average (arithmetic mean) radon exhalation flux densities (mBq m-2 s-1) and
radon exhalation fluxes (kBq s-1) for areas 1–6. The total radon exhalation flux from the site
in the dry season 2011 was 190 ± 45 kBq s-1. Approximately three quarters of the total radon
exhaled from the site originated from the overburden heap, in particular from the area around
the eastern corner of the heap.
Table 2 Average radon exhalation flux densities and radon exhalation fluxes from areas 1–6.
Description
Extent
No of points
(ha)
Flux density
Flux
(mBq m-2 s-1)
(kBq s-1)
Area 1
Former stockpile
7.2
5
410 ± 100
29 ± 7
Area 2
South edge of lake
1.6
3
380 ± 130
6±2
Area 3
North of lake, mine offices
2.5
3
220 ± 40
5±1
Area 4
West bank of lake
1.3
2
230 ± 30
3 ± 0.3
Area 5
Access road
1.7
1
260 ± 9
4 ± 0.1
Area 6
Overburden heap
14.9
15
950 ± 300
142 ± 45
Areas 1–6
Areas 1–6 combined
29.1
29
18
190 ± 45
Figure 11 Radon exhalation flux densities at the 29 selected points at RJCS
Figure 12 shows the radon exhalation flux density plotted against the soil 226Ra activity
concentration for the 29 selected measurement points. The general trend is for radon
exhalation flux density to increase with soil 226Ra activity concentration. The slope of the
linear regression best fit line (0.4 mBq m-2 s-1 per Bq kg-1) describes the relationship between
19
the two parameters. The magnitude of the radon exhalation flux density depends not only on
the soil 226Ra activity concentration but also on soil parameters such as porosity, moisture and
type, hence the scatter in the data around the line of best fit. In this context Lawrence et al
(2009) found slopes of 0.27 for compacted soil with no vegetation, and 0.61 for vegetated
woodland or rehabilitated areas for the region around the Ranger uranium mine. The slopes
for these discrete types of soil condition bracket the line of best fit determined in this study.
Rn flux density [mBq/m2/s]
5000
4000
3000
2000
1000
0
0
2000
4000
6000
8000
10000
Ra-226 [Bq/kg]
Figure 12 Radon exhalation flux density plotted against soil 226Ra activity concentration for the 29
selected measurement points. The slope of the line of best fit is 0.40 ± 0.06 mBq m-2 s-1 per Bq kg-1. The
dashed lines are the 95% confidence intervals of the line of best fit
4.3.2 Diurnal variation of airborne radon and RDP concentrations at RJCS
The results of radon and RDP concentration measurements are provided in Appendix G and
H, respectively. Figure 13 shows time series plots of the PAEC of RDP in air at RJCS (wet
and dry season) and at BBFC (dry season only). The average dry season PAEC measured
over two days at RJCS was 0.257 µJ m-3. The 24 hour average measured in the wet season
was 0.011 µJ m-3.
RDP concentrations in air show the typical diurnal variation, with higher concentrations in the
night and early morning and lower concentrations in the day. This variability is caused by the
lower wind speeds and frequently forming temperature inversions at night-time, which
effectively inhibit mixing of air masses and lead to a build-up of radon exhaled locally and its
decay products. During the day, with the onset of the south-easterlies in the dry season from
about 09:00 hrs onwards, the air is effectively mixed, and RDP concentrations at RJCS are
similar to the RDP concentration measured at BBFC (Figure 13).
The effect of exhaled radon building up in the air from local sources at RJCS during the night
can also be seen in variations of the equilibrium factor, which has been determined from the
measured airborne radon and RDP concentrations as:
E = Ceq/Cm
(1)
20
Where:
E is the equilibrium factor,
Ceq (Bq m-3) is the equivalent equilibrium concentration (EEC) of RDP, and
Cm (Bq m-3) is the measured radon activity concentration.
Figure 14 shows the three-hourly average radon concentration and radon EEC. The radon
EEC was determined from three-hourly averages of the measured PAEC of RDP in air using a
conversion factor of 179.86 Bq m-3 per µJ m-3 (UNSCEAR 2010) and assuming radioactive
equilibrium between radon and its short-lived decay products. Figure 14 also shows the
calculated equilibrium factor.
1.0
µJ/m
3
0.8
RDP BFC dry
RDP RJS dry
RDP RJS wet
0.6
0.4
0.2
0.0
6:00 12:00 18:00 0:00
6:00 12:00 18:00 0:00
6:00 12:00
time of day
Figure 13 Diurnal variation of the PAEC of RDP in air at RJCS during the dry season (red dots) and wet
season (green dots) and at BBFC during the dry season (black dots)
An equilibrium factor of 1 means that the activity concentration of each individual RDP is
equal to the activity concentration of the radon itself. This is usually the case within a couple
of hours and indicates that the radon is ‘old’ and the air mass is well mixed. During the day
the equilibrium factor at RJCS is close to 1 (Figure 14), the air is well mixed with the onset of
the south-easterlies and the radon concentration in air is generally low. Due to the low
counting statistics associated with low activity concentrations, the relative error of radon and
PAEC measurements is high, leading to the large uncertainty in the calculated equilibrium
factor at ~13:00 hrs. An equilibrium factor of 1 has been used for this data point in further
calculations made in this assessment.
Young radon will have an equilibrium factor much lower than 1, as there has not been
sufficient time for RDP to grow in and reach radioactive equilibrium with radon. This is the
case during the night at RJCS, when equilibrium factors as low as 0.1 were determined during
this study.
21
500
Bq/m3 measured
Bq/m3 EEC
Bq/m
3
400
300
200
100
1.6
1.4
1.2
E
1.0
0.8
0.6
0.4
0.2
0.0
16:00
22:00
04:00
10:00
16:00
22:00
04:00
10:00
time of day
Figure 14 Diurnal dry season variation of the radon concentration and calculated radon EEC (top) and
the equilibrium factor (bottom) at RJCS
The night-time (21:00–09:00 hrs) average RDP concentration in air within the picnic area at
RJCS from 7–9 September 2011 was 0.47 µJ m-3, approximately 10 times higher than the
daytime (09:00–21:00 hrs) average concentration of 0.044 µJ m-3. The night-time average
radon concentration within the picnic area for the same two day period was 235 Bq m-3,
approximately 7.5 times higher than the daytime average concentration of 17 Bq m-3. The
average equilibrium factor of 0.33 during the night was around two times lower than the
daytime average equilibrium factor of 0.59. Averaged over 24 hours, the equilibrium factor at
RJCS was 0.46. This is similar to the average equilibrium factor of 0.45 reported for Jabiru
East in the Northern Territory (Akber & Pfitzner 1994).
Table 3 shows the average dry season equilibrium factors determined for RJCS for various
times of the day and occupation durations. This table can be used to estimate effective RDP
concentrations across the site for various occupancy times from the radon concentrations
measured using the passive TEDs. The EEC can be calculated using equation 1 above. The
EEC (in Bq m-3) can then be converted to PAEC using equation (2) below (UNSCEAR 2010).
1 Bq m-3 = 5.56×10-6 mJ m-3.
(2)
22
Table 3 Average equilibrium factor for various occupancy times and durations.
End
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
0
0.34
0.39
0.4
0.48
0.58
0.56
0.51
0.46
0
0.43
0.42
0.52
0.64
0.61
0.54
0.48
0
0.42
0.57
0.72
0.65
0.56
0.49
0
0.73
0.86
0.73
0.59
0.50
0
1.00
0.73
0.55
0.45
0
0.46
0.33
0.26
0
0.19
0.17
0
0.05
Start
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
0
RDP concentrations at RJCS were also measured for 24 hours during the wet season on 13–14
January 2011 (Figure 13). Batchelor received 130 mm of rain in the three days preceding the
measurement and approximately 5 mm during the measurement period itself. Consequently,
the measurement is representative of peak wet season conditions. The measured RDP
concentrations were approximately 20 times lower (both during the day and night) than those
measured during the dry season. Night-time average RDP concentration (0.021 µJ m-3) was
around 10 times higher than the daytime average value (0.002 µJ m-3). The 24 hour average
RDP concentration was 0.011 µJ m-3.
4.3.3 Diurnal variation of dry season RDP concentrations at Batchelor
The diurnal variability of dry season RDP concentration in air at Batchelor is shown in Figure
13 for the three-hourly measurements made on 7–9 September 2011. The average PAEC of
RDP in air over the two day measurement period was 0.06 µJ m-3. This is effectively the same
as that measured at Batchelor by Kvasnicka et al (1992) after site rehabilitation (0.07 µJ m-3).
Figure 15 shows the ratio of the three-hourly RDP concentrations at RJCS to those at BBFC.
11
ratio of RDP RJS/BFC
RJS/BFC [dimensionless]
9
7
5
3
1
14:00
20:00
2:00
8:00
14:00
20:00
2:00
8:00
time of day
Figure 15 Ratio of the PAEC of RDP in air at RJCS to that at BBFC from 7–9 September 2011
23
There was little difference in daytime (09:00–21:00 hrs) RDP concentrations at the two sites,
with the ratio close to 1. However, night-time (21:00–09:00 hrs) RDP concentrations at RJCS
were 5 times higher on average than at BBFC. This is an effect of locally exhaled (young)
radon building up at RJCS during the night, whereas the daytime RDP concentration is that of
a well mixed air parcel representing typical regional background RDP concentrations.
4.3.4 Geographic variability of radon concentration in air
Results of individual TED radon measurements are provided in Appendix I. Figure 16 shows
the approximate magnitude of radon concentrations across the RJCS site, taken as the average
of the two TEDs deployed at each selected point.
Table 4 gives average dry season radon concentrations for the different areas at RJCS. It also
gives the corresponding RDP concentration, calculated using the average equilibrium factor
of 0.46 determined from simultaneous radon and RDP concentration measurements made at
the picnic area on 7–9 September 2011 (see section 4.3.2).
Radon and RDP concentrations measured during the two days of fieldwork (7–9 September
2011) using the RAD7 and ERDM gave averages at the picnic area of approximately 130 Bq
m-3 and 0.26 µJ m-3, respectively. The radon concentration measured during those two days
was lower than the long term average of 200 ± 40 Bq m-3 estimated from the TED
measurements. At BBFC the average RDP concentration in air on 7–9 September 2011 (0.06
µJ m-3) was also slightly lower than the two month average calculated from the two TEDs
deployed there (0.08 µJ m-3). Local weather patterns during the two days of fieldwork may be
responsible for the observed differences. For the purpose of dose calculations, the twomonthly average data from the TEDs have been used. An environmental background of 0.08
µJ m-3 is assumed for the dry season.
Table 4 Average dry season radon and RDP concentrations at RJCS from 7 July to 9 September 2011.
The PAEC of RDP in air for this study has been calculated using an average 24 hour equilibrium factor
of 0.46, determined from on site measurements made on 7–9 September 2011. Post-rehabilitation RDP
concentrations reported by Kvasnicka et al (1992) are given for comparison.
Description
Area
(ha)
No. of
TEDs
Radon
(Bq m-3)
RDP PAEC (µJ m-3)
This study
Kvasnicka
Area 1
Former stockpile
7.2
8
150 ± 30
0.38 ± 0.08
0.23
Area 2
South edge of lake
1.6
8
190 ± 60
0.48 ± 0.14
0.15
2
120 ± 20
0.30 ± 0.05
0.67
4
200 ± 40
0.51 ± 0.11
Open area
Picnic area
Area 3
North of lake
2.5
6
100 ± 40
0.25 ± 0.09
Area 4
West bank of lake
1.3
2
220 ± 60
0.57 ± 0.16
Area 5
Access road
1.7
2
120 ± 40
0.31 ± 0.09
0.12
Area 6
Overburden heap
14.9
23
110 ± 90
0.28 ± 0.23
0.09
10
60 ± 20
0.16 ± 0.04
SE-slope
9
160 ± 120
0.40 ± 0.30
NW-slope
4
120 ± 50
0.30 ± 0.14
On top
All areas
Areas 1-6
29.1
49
130 ± 50
0.33 ± 0.12
Environmental
Environmental
NA
4
31 ± 13
0.08 ± 0.03
TED30
2
30 ± 4
0.08 ± 0.01
BBFC
2
33 ± 24
0.08 ± 0.06
24
0.09
0.14
0.07
Figure 16 Two-monthly average radon in air concentrations measured at selected points at RJCS
4.4 Dust-bound LLAA radionuclide concentrations
Results of dust-bound LLAA radionuclide concentration measurements are provided in
Appendix B. Figure 17 shows the time series of the measurements made at RJCS, at the site 3
km downwind of RJCS and at BBFC. LLAA radionuclide concentrations were generally
higher at RJCS compared to BBFC. Only the last sample (collected on 7–9 September 2011)
showed higher LLAA radionuclide concentrations at BBFC. During that particular sampling
period, an equipment demonstration took place at BBFC in the vicinity of the dust sampler
which led to a small fire close to the sampler. Although the fire was quickly extinguished by
25
BBFC staff, the fire and activities associated with putting it out may have resulted in higher
concentrations of dust and ash in the air. Consequently, this sample is not considered
representative of the dust-bound LLAA radionuclide concentrations at Batchelor.
For measurements made from 4 July to 7 September 2011 the time-weighted average LLAA
radionuclide concentration at RJCS (0.181 mBq m-3) was around 30% higher than that at
BBFC (0.142 mBq m-3). This comparison is for quiescent conditions at both sites and
excludes those sampling periods where the occurrence of atypical activities may have affected
the measurement result, specifically the controlled burn off of gamba grass (30 June to 4 July
2011), the fire at BBFC (7–9 September 2011) and the occupation of the RJCS site by study
team (7–9 September 2011).
The LLAA radionuclide concentration measurements at RJCS were made while the site was
closed to the public. Given that the actual airborne LLAA radionuclide concentration may be
higher when the site is frequented by the public, with the ground being more disturbed by
pedestrian or vehicular traffic, a dust sample was collected in the two day period when the
fieldwork was conducted (7–9 September 2011), with the dust sampler positioned in the
middle of the picnic area. The field team camped at the site specifically so as to provide a
more realistic dust generation scenario. Dust generated by the activities of the study team,
including camping and vehicular movements, would have been collected in this sample. The
LLAA radionuclide concentration measured in this sample (0.289 mBq m-3) was
approximately two times higher than the average LLAA radionuclide concentration in air at
the BBFC. This higher value will be used for subsequent estimates of doses to the public from
the dust inhalation pathway at RJCS.
At the site 3 km downwind of RJCS, the LLAA radionuclide concentration in the dust sample
taken during and immediately after the burn off (0.184 mBq m-3, collected on 30 June–4 July
2011) was around 40% higher than that in the subsequent sample (0.130 mBq m-3, collected
on 4–11 July 2011). The time-weighted average LLAA radionuclide concentration at BBFC
for samples collected from 30 June to 7 September 2011 (0.138 mBq m-3) has been calculated
to represent environmental background levels. The implication is that the LLAA radionuclide
concentrations at the downwind site during and immediately after the burn off were around
1.3 times higher than background and then reduced to background-equivalent levels. The
LLAA radionuclide concentration on-site at RJCS during and immediately after the burn off
(0.217 mBq m-3) was around 1.6 times higher than the background level calculated for BBFC.
0.40
RJS lake burn
fieldwork
0.35
0.30
mBq/m 3
0.25
0.20
BBFC
0.15
RJS Lake
0.10
down wind
0.05
0.00
Date
Figure 17 Time series of LLAA radionuclide concentrations in dust samples collected at RJCS lake, at
the site 3 km downwind of the burn off of gamba grass and at BBFC
26
4.5 Radionuclide and metal concentrations in water and bushfoods
Figure 18 shows the locations where water and bushfood samples were collected. Water
samples were collected over the duration of the project from RJCS lake and from Meneling
Creek at sites upstream, midstream and downstream of the overburden heap. Water samples
were also collected from two drains at the southeast and northwest sides of the overburden
heap in the wet season. The total bushfood collection comprised 15 fruits, one yam and 80
mussels. The fruit samples were taken from trees growing across the RJCS site, including the
picnic area. The yam was taken from the picnic area. All mussels were collected from the
lake.
Figure 18 Water and bushfood sampling locations at RJCS
27
4.5.1 226Ra and 210Po activity and metal concentrations in water
Table 5 gives the results of 226Ra and 210Po activity concentrations and metal and sulfate (SO4)
concentrations in individual water samples from both Meneling Creek and RJCS lake. Figure
19 shows time series plots for 226Ra activity and selected metals and SO4 concentrations in
Meneling Creek. Figure 20 shows concentrations of 226Ra activity and selected metals
measured in RJCS lake water.
In the 2010 dry season (October measurement), total water 226Ra activity and uranium
concentrations were similar at sampling locations upstream, midstream and downstream of
the overburden heap, with the mid- and downstream concentrations being slightly higher than
those upstream. In the wet season (January measurement), 226Ra activity and uranium
concentrations spiked at the downstream sampling location (the midstream sampling location
was not accessible during this time). Relative to the dry season, wet season 226Ra activity and
uranium concentrations were 20 and 50 times higher, respectively, at the downstream site.
There was little difference in the upstream concentrations between the dry and the wet season.
Concentrations decreased toward the end of the wet season (April measurement), with the
mid- and downstream values being slightly higher than those upstream. By the 2011 dry
season (September measurement), 226Ra activity concentrations were at levels similar to those
from the previous dry season. The SO4 time series was similar to that of 226Ra and uranium,
with concentrations downstream about 85 times higher during the wet season than the dry
season.
Water samples collected from a drain at the southeast side of the overburden heap in January
and March 2011 (samples RJX11001 and RJX11007) showed 226Ra and 210Po activity and
uranium concentrations of up to 270 mBq l-1, 111 mBq l-1 and 209 µg l-1, respectively. The
SO4 concentration in these samples was up to 500 mg l-1. 226Ra and 210Po activity and uranium
and SO4 concentrations in water collected from a drain at the north side of the overburden
heap in March 2011 (sample RJX 11008) were 78.4 mBq l-1, 11.7 mBq l-1, 27 µg l-1 and 156
mg l-1, respectively. Radionuclide, uranium and SO4 concentrations in water from both drains
were elevated relative to concentrations in Meneling Creek.
The ion balance [Mg+Ca]mol : [SO4]mol (ion balance ratio) measured in the water samples from
the drains is shown in Figure 19 as well. During peak wet season conditions in January the
magnesium and calcium cations in samples from both the drains and from Meneling Creek
downstream are accounted for almost entirely by the sulfate (SO4)2- anion, with the ion
balance ratio close to one. In the drier months of the year, an additional anion, most likely
bicarbonate ((HCO3)2-, not measured in this study), would be required to balance magnesium
and calcium in Meneling Creek water.
The time-series ion concentration and ion ratio data (Figure 19) implies that the biggest
source of major cations and SO4 in Meneling Creek, at least in the early to mid part of the wet
season, is seepage from the overburden heap. Most likely, rainwater percolates through the
overburden heap during peak wet season conditions, dissolving magnesium and calcium
sulfates and leaching 226Ra and uranium from the relatively uranium-rich material contained
therein. This water then drains from the overburden heap and the radionuclides, metals and
SO4 wash into Meneling Creek at a point upstream of the downstream sampling location used
in this study. The magnesium and calcium concentration in Meneling Creek downstream is
diluted relative to the dry season concentrations, but sulfate concentrations increase. The
measured concentrations profiles of iron, copper, lead and zinc indicate inputs of these metals
from upstream of the overburden heap during the wet season.
28
226
Ra activity and uranium concentrations in RJCS lake water (Figure 20) were higher with
the onset of the wet season (late 2010), with a decreasing trend as the season progressed, and
the lowest concentrations occurring at the end of the wet. Concentrations increased slightly
with the onset of the dry season. Calcium, magnesium, barium and rubidium concentrations
showed behaviour similar to 226Ra activity and uranium concentrations, whereas SO4
concentrations remained higher during the wet season and only decreased with the beginning
of the dry season. Lead and copper concentrations in lake water were low throughout the year
and did not exhibit a trend.
29
Table 5 Total water 226Ra and 210Po activity (at time of separation) concentrations and metal and SO4 concentrations in RJCS water samples. Typical relative uncertainty for
ICPMS analyses is 10%.
Collection
date
Location
RJX10023
25/10/10
Meneling Ck u/s
RJX10024
25/10/10
RJX10025
25/10/10
Sample
226Ra
210Po
SO4
(mBq l-1)
Separation
date
U
(µg l-1)
Ba
(µg l-1)
Ca
(mg l-1)
Mg
(mg l-1)
Cu
(µg l-1)
Fe
(µg l-1)
Zn
(µg l-1)
Pb
(µg l-1)
2.17 ± 0.28
1.45 ± 0.38
7/3/2011
7/3/2011
*30
*30
n.r.
Meneling Ck d/s
3.11 ± 0.32
1.06 ± 0.24
7/3/2011
*9.1
*8.9
*23
*24
*29
*30
n.r.
*0.3
*1.4
*1.2
n.r.
1.08 ± 0.28
*24
*24
n.r.
3.51 ± 0.33
*8.6
*9.7
*0.3
Meneling Ck m/s (stagnant)
*0.43
*0.76
n.r.
n.r.
*1.1
*1.1
n.r.
*1.4
n.r.
*1
*0.8
(mBq
l-1)
n.r.
(mg l-1)
*1.1
*0.9
*0.9
RJX10026
25/10/10
Meneling Ck m/s (flowing)
2.15 ± 0.33
0.96 ± 0.28
7/3/2011
*0.55
*0.48
RJX10027
25/10/10
Lake
2.71 ± 0.34
7/3/2011
*5.4
*17
*9.2
*13
RJX10053
07/12/10
Lake
30.3 ± 1
*28.1 ± 0.7
*0.3
*0.1
2.81 ± 0.14
10/3/2011
5.9
18
9.5
13
0.6
100
8.9
0.7
0.6
RJX11001
14/01/11
Drain SE side of heap
238 ± 10
20.1 ± 0.8
7/3/2011
209
13
72
91
1.4
<20
5.7
2.0
500
RJX11002
14/01/11
Lake
42.2 ± 1.9
5.36 ± 0.44
7/3/2011
5.3
21
8.6
12
0.4
40
2
0.2
1.1
RJX11003
14/01/11
Meneling Ck u/s
3.23 ± 0.44
4.45 ± 0.36
7/3/2011
0.38
20
16
15
3.4
700
13
1.6
2.6
RJX11004
14/01/11
Meneling Ck d/s
63.9 ± 3.8
17.3 ± 1
7/3/2011
26
13
15
21
0.8
180
1.2
1.1
85
RJX11005
09/03/11
Overflow from lake
21.1 ± 1
4.65 ± 0.28
30/6/2011
2.5
13
6
8.5
0.1
100
2
0.6
1.3
RJX11006
09/03/11
Lake
20.3 ± 0.9
3.64 ± 0.34
30/6/2011
2.3
13
5.9
8.5
0.7
80
0.9
0.4
1.2
RJX11007
09/03/11
Drain SE side of heap
270 ± 6
111 ± 6
30/6/2011
20
14
17
24
1.4
880
3.6
3.6
94
RJX11008
09/03/11
Drain NW side of heap
78.4 ± 2.9
11.7 ± 0.8
30/6/2011
27
29
47
42
0.9
160
29
1.1
156
RJS11001
12/04/11
Meneling Ck u/s
2.38 ± 0.39
2.25 ± 0.39
30/6/2011
0.21
14
13
12
0.9
1000
2.1
0.2
0.5
RJS11002
12/04/11
Meneling Ck m/s
3.32 ± 0.55
1.68 ± 0.46
30/6/2011
0.95
14
12
12
0.6
940
0.5
0.2
0.6
RJS11003
12/04/11
Meneling Ck d/s
6.7 ± 0.54
2.73 ± 0.36
30/6/2011
2.0
14
13
14
0.6
880
0.9
0.2
8
RJS11004
12/04/11
Lake
15.7 ± 0.9
2.98 ± 0.28
30/6/2011
1.6
101
5
7.9
0.1
60
1.2
0.6
1.4
RJS11013
31/05/11
Meneling Ck d/s
2.33 ± 0.55
1.32 ± 0.26
30/6/2011
0.72
9.6
19
23
0.3
240
0.5
0.3
11
RJS11014
31/05/11
Meneling Ck m/s
1.67 ± 0.4
1.69 ± 0.19
26/7/2011
0.37
9.4
18
21
0.3
240
2
0.9
0.5
RJS11015
31/05/11
Meneling Ck u/s
1.75 ± 0.44
1.76 ± 0.17
26/7/2011
0.32
11
19
21
0.3
340
0.7
0.25
0.9
RJS11016
31/05/11
Lake
22.7 ± 1
2.91 ± 0.21
1.22 ± 0.29
0.3
*0.6
0.3
1.7 ± 0.35
10
*31
2.2
Meneling Ck u/s
7.5
*24
120
09/09/11
1.77
*0.41
14
RJS11048
26/7/2011
7/11/2011
N.A.
1.5
n.r.
1
*0.8
RJS11049
09/09/11
Meneling Ck d/s
3.03 ± 0.35
0.95 ±0 .29
7/11/2011
N.A.
33.1 ± 1.5
6.70 ± 0.78
7/11/2011
*0.6
*0.5
n.r.
Lake
*31
*14
1.1
09/09/11
*24
*11
N.A.
RJS11050
*0.81
*5.11
N.A.
<1
n.r.
N.A.
N.A.
*Concentrations given are for the filtered fraction. N.A.: not analysed; n.r.: not reliable; u/s, m/s, d/s: upstream, midstream and downstream of overburden heap.
30
n.r.
n.r.
*0.9
*0.6
Meneling Creek
mid
60
40
20
u/s
mid
mid
u/s
1.6
d/s
Pb [ug/L]
Mg [mg/L]
20
15
10
u/s
mid
d/s
1.2
0.8
0.4
0
0
u/s
mid
1000
d/s
(Mg+Ca):SO4
60
14
u/s
d/s
mid
SP drain
100
10
u/s
mid
12
Zn [ug/L]
U [ug/L]
0
5
0
SO4 [mg/L]
2
1
25
5
0
10
30
10
20
15
d/s
mid
u/s
3
d/s
15
40
20
0
20
80
4
d/s
5
0
25
mid
u/s
25
d/s
Cu [ug/L]
u/s
Ca [mg/L]
226Ra [mBq/L]
80
10
8
6
4
2
1
0
Figure 19 Time series of total 226Ra activity concentration, selected metal and SO4 concentrations and [Mg+Ca]mol:[SO4]mol in Meneling Creek
31
d/s
25
8
6
20
15
1.6
Pb [ug/L]
Ca [mg/L]
10
1.2
0.8
2
5
0
0
0
0
7
14
140
4
6
12
5
10
6
80
60
4
40
1
2
20
0
0
0
25
80
1.4
0.6
0.4
0.2
0
Ba [ug/L]
1
20
15
0
1
10
60
50
40
30
20
5
10
0
0
2
1
70
1.2
0.8
3
Cu [ug/L]
8
Rb [ug/L]
3
100
Fe [ug/L]
4
0.4
120
Mn [ug/L]
U [ug/L]
30
10
2
SO4 [mg/L]
35
12
4
20
Mg [mg/L]
226Ra [mBq/L]
40
14
Al [ug/L]
Lake
60
0.8
0.6
0.4
0.2
0
Figure 20 Time series of total 226Ra activity concentration and selected metal and SO4 concentrations for RJCS lake water
32
4.5.2 226Ra, 228Ra and 210Pb activity and metal concentrations in freshwater mussels
Table 6 gives the results of 238U, 226Ra, 228Ra, 228Th and 210Pb activity concentration
measurements in mussel flesh. Figure 21 shows radionuclide activity concentrations in mussel
flesh plotted as a function of age class. Activity concentrations have been decay corrected to
account for the time elapsed between mussel collection and radioactivity analysis. 210Pb
activity concentration has been corrected to account for both its decay and for the ingrowth of
210
Pb from the decay of 226Ra. Similarly, 228Th activity concentration has been corrected to
account for both its decay and for the ingrowth of 228Th from 228Ra. It was assumed that no
thorium is incorporated into mussels from the water column.
Table 7 gives the results of metal concentrations in mussel flesh determined via ICPMS.
Figure 22 shows metal concentrations in mussel flesh plotted as a function of mussel age.
Table 6 Radionuclide activity concentrations (Bq kg-1 dry weight) in mussel flesh from RJCS lake (decay
corrected to the time of collection) determined via ICPMS, gamma spectrometry or alpha spectrometry.
n: number of mussels per age class.
eriss ID
age
dry/wet
n
238U
226Ra
RJS10082
0.5
0.085
8
10.7 ± 1.1
RJS10083
1
0.107
16
RJS10084
2
0.112
RJS10085
3
RJS10086
210Pb
*
228Ra
228Th
704 ± 28
n.d.
n.d.
n.d.
8.3 ± 0.8
786 ± 7
63 ± 17
< 20
< 10
18
6.2 ± 0.6
193 ± 3
142 ± 11
11 ± 5
6±2
0.124
7
5.7 ± 0.6
963 ± 8
238 ± 17
30 ± 8
4±3
4
0.086
5
9.9 ± 1.0
2373 ± 18
291 ± 32
34 ± 14
16 ± 6
RJS10087
5
0.097
13
7.5 ± 0.8
3161 ± 18
362 ± 19
39 ± 8
23 ± 3
RJS10088
6
0.109
2
11.7 ± 1.2
2666 ± 22
145 ± 41
34 ± 19
29 ± 8
RJS10089
7
0.070
6
15.9 ± 1.6
6345 ± 36
416 ± 36
110 ± 17
60 ± 7
RJS10090
8
0.086
2
10.1 ± 1.0
4295 ± 31
605 ± 53
53 ± 27
47 ± 9
RJS10091
9
0.063
1
14.8 ± 1.5
*
2330 ± 313
n.d.
n.d.
n.d.
5.6 ± 0.6
*
n.d.
n.d.
n.d.
6.2 ± 0.6
*
n.d.
n.d.
n.d.
RJS10092
10
RJS10093
11
0.129
1
0.095
1
1020 ± 132
3900 ± 900
* samples analysed via alpha spectrometry. U was determined via ICPMS, and concentrations multiplied with (12.35 Bq /kg)U238/(mg/kg) U. n.d. not determined.
Table 7 Metal concentrations (mg kg-1 dry weight) determined via ICPMS in flesh from mussels from
RJCS lake. Typical relative uncertainties are ±10%. n: number of mussels per age class.
eriss ID
age
dry/wet
n
Al
Ba
Ca
Cu
Fe
Mg
Mn
Pb
Rb
U
Zn
RJS10082
0.5
0.085
8
<50
189
6260
6.6
2660
750
1300
2.2
7.12
0.87
82
RJS10083
1
0.107
16
50
236
7250
6.6
2360
720
1260
2
5.97
0.67
101
RJS10084
2
0.112
18
50
144
3930
4.8
2680
610
627
3.8
6.19
0.5
113
RJS10085
3
0.124
7
<50
277
4340
3.8
3520
580
1060
4.2
4.6
0.46
116
RJS10086
4
0.086
5
50
593
10700
4
5840
790
1440
4.8
6.35
0.8
159
RJS10087
5
0.097
13
<50
1400
6760
4
7940
750
1560
7
5.65
0.61
156
RJS10088
6
0.109
2
<50
568
8500
4
4720
690
1680
1.8
4.26
0.95
100
RJS10089
7
0.070
6
50
1850
13800
6
12900 1060
3380
8
6.78
1.29
176
RJS10090
8
0.086
2
100
949
8970
6.2
11000 730
2640
10.6
5.55
0.82
141
RJS10091
9
0.063
1
50
942
11700
6.6
9020
1060
3070
4.2
7
1.2
118
RJS10092
10
0.129
1
<50
155
2110
3
9140
440
423
11.4
3.12
0.45
150
RJS10093
11
0.095
1
<50
711
7590
4.8
8880
780
2260
9
4.54
0.5
154
33
120
7000
y = 396x + 484
R² = 0.53
y = 10.14x - 6.25
R² = 0.59
100
Ra-228 [Bq/kg]
Ra-226 [Bq/kg]
6000
5000
4000
3000
2000
80
60
40
20
1000
0
0
5
0
10
0
700
10
70
y = 59.0x + 17.2
R² = 0.67
60
Th-228 [Bq/kg]
600
Pb-210 [Bq/kg]
5
mussel age [y]
mussel age [y]
500
400
300
200
50
40
30
20
100
10
0
0
0
5
mussel age [y]
0
10
5
mussel age [y]
10
Figure 21 Decay corrected 226Ra, 228Ra, 228Th and 210Pb activity concentrations in mussel flesh plotted
versus mussel age. The line is a linear fit to the data points. Radium and lead activity concentrations
increase with mussel age (p≤0.05, see Table 8). The increase in 228Th is due to the ingrowth from its
parent 228Ra. The open diamond in the 226Ra plot has not been used for the linear regression
To determine radionuclide and metal bioaccumulation characteristics in the mussels, Table 8
gives a correlation matrix for the variables mussels age, barium, calcium, copper, iron,
magnesium, manganese, lead, uranium, 226Ra, 228Ra and 210Pb activity concentration.
As reported for other sites in the Northern Territory of Australia (Bollhöfer et al 2011;
Bollhöfer 2012; Johnston et al 1987; Ryan et al 2008a) radium and lead bioaccumulate in the
flesh of freshwater mussels. This is because radium and lead are incorporated into calcium
phosphate granules in mussel flesh (Jeffree &Simpson 1984) leading to a long biological halflife for radium in freshwater mussels of ~10 years and a slightly lower biological half-life for
lead (Johnston et al 1987; Bollhöfer et al 2011). Iron and zinc are additional metals that
bioacumulate in mussel flesh, whereas uranium, copper, magnesium, calcium and barium do
not exhibit a significant increase in concentration with mussel age. As expected, the alkaline
earth metal concentrations in mussel flesh correlate well with each other. In addition, there is
a positive correlation between iron, manganese and lead.
34
1200
12
y = 8.9x + 697
R² = 0.032
600
400
200
8
6
4
2
0
5
10
5
6000
4000
1
6000
4000
2000
0
0
10
0
y = 122x + 1050
R² = 0.215
2500
2000
1500
1000
500
0
5
mussel age [y]
10
0.4
10
Zn [mg/kg]
Mn [mg/kg]
3000
0.6
0
5
mussel age [y]
4000
3500
0.8
0.2
0
y = 59.6x + 338
R² = 0.152
y = 0.0093x + 0.708
R² = 0.014
1.2
8000
2000
10
1.4
U [mg/kg]
Fe [mg/kg]
Ca [mg/kg]
8000
0
5
mussel age [y]
10000
2000
1800
1600
1400
1200
1000
800
600
400
200
0
y = -0.07 + 5.4
R² = 0.039
0
y = 817x + 2193
R² = 0.65
12000
10000
5
mussel age [y]
2
10
14000
y = 202x + 6542
R² = 0.045
0
3
mussel age [y]
16000
12000
4
0
0
mussel age [y]
14000
5
1
0
0
Ba [mg/kg]
6
Cu [mg/kg]
800
7
y = 0.71x + 1.8
R² = 0.555
10
Pb [mg/kg]
Mg [mg/kg]
1000
0
5
mussel age [y]
10
200
180
160
140
120
100
80
60
40
20
0
5
mussel age [y]
10
y = 4.9x + 103
R² = 0.354
0
5
10
mussel age [y]
Figure 22 Selected metal concentrations in mussel flesh (dry weight) plotted against mussel age. The line is a linear fit to the data points. Iron, lead and zinc concentrations
increase with mussel age (p≤0.05, see Table 8)
35
Table 8 Correlation matrix showing Pearson correlation coefficients (grey) and p-values for the variables
mussel age, selected metal concentrations and 226Ra, 228Ra, and 210Pb activity concentrations. Variable
pairs showing a p-value ≤ 0.05 (significant correlation) are shown in bold font.
age
Ba
Ba
Ca
Cu
Fe
Mg
Mn
Pb
U
Zn
226
Ra
210
Pb
0.39
0.21
Ca
Cu
Fe
Mg
Mn
Pb
U
Zn
226
Ra
210
Pb
228
Ra
0.21
0.74
0.51
0.01
-0.20
0.20
0.50
0.54
0.54
0.10
0.81
0.77
0.51
0.05
<0.01
<0.01
0.09
0.88
0.18
0.73
0.92
0.63
0.46
0.58
0.01
<0.01
0.03
0.14
0.46
0.80
0.88
0.56
0.70
0.89
0.13
<0.01
<0.01
0.06
0.01
<0.01
0.75
0.36
-0.05
-0.25
0.80
-0.11
0.21
0.01
0.25
0.88
0.43
<0.01
0.75
0.52
0.12
0.61
0.87
0.58
0.41
0.85
0.79
-0.18
0.72
0.04
<0.01
0.05
0.18
<0.01
<0.01
0.58
0.59
0.66
0.34
-0.32
0.79
0.24
0.36
0.76
0.05
0.04
0.02
0.28
0.31
<0.01
0.46
0.25
<0.01
0.87
0.56
0.90
0.74
0.17
0.84
0.63
0.83
0.50
0.55
0.70
0.05
<0.01
0.01
0.60
<0.01
0.03
<0.01
0.10
0.06
0.01
0.82
0.67
0.46
0.21
0.88
0.43
0.72
0.98
0.37
0.71
0.75
0.01
0.07
0.25
0.62
<0.01
0.29
0.04
<0.01
0.37
0.05
0.03
0.77
0.88
0.79
0.23
0.91
0.86
0.92
0.66
0.83
0.77
0.95
0.67
0.03
<0.01
0.02
0.58
<0.01
0.01
<0.01
0.08
0.01
0.03
<0.01
0.07
In addition to the long biological half-life of radium, the activity concentration of radium (and
also lead) in mussel flesh is governed by a number of other factors, such as water chemistry,
mussel metabolic rate and mussel condition. Calcium water concentration in particular plays
an important role, as radium competes with calcium for adsorption sites in mussel tissue
(Jeffree & Simpson 1986). Low radium:calcium ratios in the water will lead to lesser uptake
of radium in mussels and vice versa (Bollhöfer et al 2011).
To parameterize the uptake of radionuclides (and metals in general) into mussels (and other
biota) the concept of concentration ratio (or uptake factor) is commonly used (IAEA 2010).
The mussel concentration ratio used in this study is defined as the ratio of the radionuclide
activity concentration in mussel tissue (wet weight) to the activity concentration of the
respective radionuclide in total water (filtered + particulate phases).
Measured 226Ra activity concentration in water from RJCS was in the range ~20–40 mBq l-1
(Figure 20). The average concentration over the sampling period (October 2010–September
2011) was 26.7 mBq l-1. The 226Ra concentration ratio in a bulk mussel sample of all age
classes was calculated to be 5900, assuming an age distribution of mussels collected in RJCS
36
in December 2010. This value is somewhat smaller than the concentration ratios measured in
the South Alligator River and lower than concentration ratios determined for Magela Creek
(Bollhöfer et al 2011). The low calcium concentrations in water contribute to the high radium
concentration ratios in Magela Creek, whereas radium uptake in mussels in RJCS lake is
much lower due to the higher concentrations and ameliorating effects of calcium and
magnesium in the water.
226
Ra concentration ratios depend on mussel age, as mussels continuously bioaccumulate
radium in their tissue from the water. The older a mussel, the higher the 226Ra activity
concentration in its tissue and the higher the concentration ratio. Consequently, concentration
ratios depend on the age distribution of a bulk mussel sample, or for ingestion dose
assessment purposes, on the age distribution of the mussels consumed.
4.5.3 226Ra and 210Po activity concentrations in fruit and yam
Table 9 gives dry weight 226Ra and 210Po activity concentrations in the collected fruits, yam
and associated soils. It also gives the dry-to-wet mass ratios for the samples and concentration
ratios for 226Ra accumulation in fruits and yam. The 210Po activity concentrations have been
corrected to the date of chemical separation for analysis. They have not been corrected for
decay of 210Po or ingrowth of 210Po from 210Pb decay occurring between the collection and
separation dates. The 226Ra activity concentrations in fruits and yam from RJCS are similar to
those that have been reported for the same type bushfoods growing at other sites in northern
Australia (Ryan et al 2005).
Table 10 gives metal concentrations in fruits and yam measured through ICPMS analysis.
Table 11 gives a correlation matrix showing Pearson’s correlation coefficient for linear
relationships between metals and 226Ra concentrations across all types of fruit and yam
varieties collected from RJCS as part of this study.
37
Table 9 226Ra and 210Po activity concentration (dry weight) in fruits, yam and associated soils, dry-to-wet sample mass ratio and 226Ra concentration ratio (CR) (fresh weight
food item to dry weight soil). Photos of cluster fig, white currant, passionfruit and gooseberry are shown in Appendix J.
eriss ID
Sample type
Collection
date
Easting
Northing
Location and common name
Dry/wet
226
Ra
(Bq kg-1)
CR (226Ra)
210
Po
(Bq kg-1)
210
RJX10028
Passiflora foetida
25/10/10
716591
8557175
113 ± 5
0.0043 ± 0.0002
9.52 ± 0.61
29/03/11
Soil
25/10/10
716591
8557175
Edge of stockpile near lake
Passion fruit
0.32
RJX10029
RJX10030
Ficus racemosa
25/10/10
716655
8557209
0.0133 ± 0.0007
7.26 ± 0.27
29/03/11
Soil
25/10/10
716630
8557195
Near lake
Cluster fig
0.22
RJX10031
RJX10049
Ficus racemosa
11/11/10
716595
8557185
0.0148 ± 0.0005
22.8 ± 0.9
29/03/11
Soil
11/11/10
716595
8557185
Near stockpile
Cluster fig
0.21
RJX10050
RJX10051
Flueggea virosa
11/11/10
716256
8556640
0.0011 ± 0.0001
0.93 ± 0.18
29/03/11
Soil
11/11/10
716256
8556640
Meneling Ck upstream
White currant
0.24
RJX10052
RJX10055
Syzygium nervosum
30/11/10
716256
8556624
Meneling Ck upstream
0.38
0.0261 ± 0.0018
3.07 ± 0.29
29/03/11
RJX10056
Soil
30/11/10
716256
8556624
RJX10057
Syzygium nervosum
30/11/10
716188
8556724
RJX10058
Soil
30/11/10
716188
8556724
RJX10059
Ficus congesta
30/11/10
715880
8557217
0.0162 ± 0.0006
1.46 ± 0.09
29/03/11
RJX10060
Soil
30/11/10
715880
8557217
RJX10061
Flueggea virosa
30/11/10
715761
8557288
RJX10062
Soil
30/11/10
715761
8557288
RJX10063
Ficus adenosperma
30/11/10
715761
8557288
0.0236 ± 0.0008
4.54 ± 0.27
29/03/11
RJX10064
Soil
30/11/10
715761
8557288
RJX10065
Ficus congesta
30/11/10
715761
8557288
0.0143 ± 0.0006
1.46 ± 0.08
29/03/11
RJX10066
Soil
30/11/10
715761
8557288
RJX10067
Flueggea virosa
30/11/10
716256
8556640
0.0028 ± 0.0002
1.01 ± 0.07
29/03/11
RJX10068
Soil
30/11/10
716256
8556640
RJX10069
Physalis minima
30/11/10
716648
8557199
0.014 ± 0.0007
<0.533
29/03/11
RJX10070
Soil
30/11/10
716545
8557215
RJS11005
Terminalia ferdinandiana
31/05/11
716664
8557850
0.013 ± 0.0007
6.67 ± 0.47
7/11/2011
RJS11006
Soil
31/05/11
716664
RJS11007
Yam
31/05/11
0.0021 ± 0.0001
1.40 ± 0.26
7/11/2011
RJS11008
Soil
31/05/11
Po
separation date
8523 ± 45
80.2 ± 3.5
1319 ± 9
228 ± 6
3158 ± 18
0.45 ± 0.04
100 ± 2
4.3 ± 0.3
61.8 ± 0.6
Meneling Ck downstream
0.35
2.7 ± 0.2
0.0159 ± 0.0014
59.8 ± 0.6
Meneling Ck downstream
Fig
0.11
Meneling Ck downstream
White currant
0.38
Meneling Ck downstream
Fig
0.20
Meneling Ck downstream
Fig
0.08
Same bush as RJX10051
White currant
0.26
Near lake
Gooseberry
0.19
Top of hill NW of lake
Billygoat plum
0.88
8557850
716640
8557191
Under fig tree near lake
0.13
716640
8557191
14.3 ± 0.4
100 ± 1
<18.7
143 ± 1
15.4 ± 0.4
133 ± 1
12.6 ± 0.4
70.4 ± 0.6
0.8 ± 0.1
75.7 ± 0.7
10.1 ± 0.4
137 ± 1
3.1 ± 0.1
210 ± 3
11.1 ± 0.3
718 ± 6
38
RJS11009
Ficus racemosa
31/05/11
716226
8556652
RJS11010
Soil
31/05/11
716226
8556652
RJS11011
Physalis minima
31/05/11
716561
8557558
RJS11012
Soil
31/05/11
716561
8557558
Meneling Ck upstream
Cluster fig
0.24
N edge of lake in erosion gully
Gooseberry
0.18
5.4 ± 0.2
0.023 ± 0.0016
1.22 ± 0.09
7/11/2011
0.0098 ± 0.0002
3.30 ± 0.19
7/11/2011
55.8 ± 1.4
40 ± 0.5
748 ± 6
Table 10 Metal concentrations (mg kg-1) in fruits and the yam collected from RJCS (see sample type and location information in Table 9 above).
Sample ID
Al
Ba
Ca
Cd
Co
Cr
Cu
Fe
K
Mg
Mn
Pb
Sr
U
Zn
RJX10028
100
3.35
1880
0.7
1.35
<10
11.4
140
27200
1580
25.8
0.8
1.6
0.68
41
RJX10030
<50
27.7
7600
0.5
0.35
<10
9.6
100
27800
2810
36.5
0.2
5.7
0.15
22
RJX10049
200
12.8
6230
0.6
0.95
<10
9.4
60
33000
3080
22.4
0.2
2
0.13
23
RJX10051
100
3.3
2900
<0.05
<0.05
<10
6.4
100
13600
1480
11.6
<0.2
4
0.02
6
RJX10055
350
37.8
15300
<0.05
0.2
<10
16
80
18700
5540
117
<0.2
15.3
0.03
16.5
RJX10057
50
8.7
10100
0.1
0.1
<10
10.2
60
12200
3870
49.7
<0.2
9.35
0.02
14
RJX10059
250
8.65
10900
0.15
0.85
<10
20
120
33800
3940
56.1
<0.2
10.3
0.14
35
RJX10061
900
4.4
3570
<0.05
0.2
<10
7.2
80
13200
1590
11.7
0.2
4.65
0.06
8.5
RJX10063
100
16.5
25500
0.05
1.3
<10
9.2
160
21800
5590
32.4
0.6
21.2
0.53
41.5
RJX10065
<50
9.5
9930
0.2
0.65
<10
19.6
100
35400
5330
23.9
<0.2
10.2
0.05
23
RJX10067
<50
3.45
3520
<0.05
0.05
<10
7.2
80
15500
1590
16.8
2.2
4.65
0.03
11.5
RJX10069
<50
2.3
1040
<0.05
0.2
<10
14.6
120
32800
2420
15.5
<0.2
0.1
0.02
32
RJS11005
30
1.95
2340
N.A.
N.A.
N.A.
5.6
80
N.A.
1200
30.6
<0.2
N.A.
0.04
7
RJS11007
<10
2.1
2810
N.A.
N.A.
N.A.
4.2
40
N.A.
1290
10.6
0.2
N.A.
0.07
20.5
RJS11009
50
22.7
17200
N.A.
N.A.
N.A.
20.2
90
N.A.
5180
76.7
<0.2
N.A.
<0.01
36
RJS11011
40
13.2
4910
N.A.
N.A.
N.A.
17.6
190
N.A.
8260
33.8
<0.2
N.A.
0.34
45.5
39
Table 11 Correlation matrix showing Pearson correlation coefficients (grey background) and p-values for
the variables 226Ra activity and selected metal concentrations in fruits and the yam collected from RJCS.
Variable pairs showing a p-value ≤0.05 (significant correlation) are shown in bold font.
226Ra
Al
Al
Ba
Ca
Cd
Co
Cu
Fe
K
Mg
Mn
Pb
Sr
U
0.16
0.65
Ba
Ca
Cd
Co
Cu
Fe
K
Mg
Mn
Pb
Sr
U
Zn
0.07
0.00
0.81
0.99
-0.18
-0.14
0.64
0.53
0.68
0.01
0.83
0.14
0.01
-0.77
0.02
0.83
0.98
0.05
0.47
-0.48
-0.09
0.33
0.27
0.17
0.27
0.79
0.32
0.56
-0.11
-0.16
0.41
0.38
-0.33
0.12
0.69
0.63
0.12
0.14
0.47
0.74
-0.04
-0.27
0.06
0.20
-0.12
0.66
0.42
0.89
0.42
0.82
0.45
0.80
0.03
0.11
0.43
-0.24
0.03
-0.02
0.34
0.47
0.67
0.32
0.19
0.57
0.94
0.96
0.46
0.14
0.02
0.31
-0.09
-0.26
0.57
0.62
-0.86
0.19
0.72
0.55
0.26
0.75
0.44
0.02
0.01
0.01
0.57
0.00
0.03
0.42
-0.20
-0.08
0.81
0.59
-0.55
-0.15
0.55
-0.02
-0.06
0.52
0.48
0.81
0.00
0.02
0.20
0.67
0.03
0.943
0.85
0.04
-0.44
-0.65
-0.35
-0.10
-0.09
-0.30
-0.00
0.13
-0.44
-0.17
-0.11
0.38
0.35
0.44
0.84
0.91
0.56
0.99
0.78
0.38
0.71
0.81
-0.42
-0.14
0.54
0.97
-0.86
0.20
0.26
0.29
-0.14
0.85
0.56
-0.04
0.20
0.74
0.07
0.00
0.01
0.55
0.42
0.37
0.67
0.00
0.06
0.94
0.33
-0.28
-0.04
0.28
0.32
0.85
0.10
0.68
0.18
0.24
-0.06
-0.02
0.19
0.35
0.43
0.90
0.32
0.48
0.00
0.73
0.01
0.58
0.38
0.84
0.96
0.57
0.20
-0.36
0.18
0.36
0.08
0.82
0.59
0.74
0.65
0.59
0.14
-0.14
0.22
0.76
0.47
0.28
0.51
0.17
0.87
0.00
0.02
0.00
0.02
0.02
0.60
0.77
0.49
0.00
5 Dose assessment
5.1 The concept of Representative Person
The ICRP recommends that a Representative Person should be used to assess the doses
received by the public for the purpose of radiation protection (ICRP 2006). The
Representative Person is defined as an individual receiving a dose that is representative of the
more highly exposed individuals in the population. The habits (e.g. consumption of
foodstuffs, breathing rate, location, usage of local resources, etc) used to characterise the
Representative Person should be typical habits of a small number of individuals
representative of those most highly exposed and not the extreme habits of a single member of
the population.
40
For a rehabilitated uranium mine site, such as RJCS, the relative importance of different
exposure pathways to the dose received by the public will depend on site access and land use.
The RJCS site may be used for short-term visits for picnics and swimming and for long-term
visits for camping and food gathering activities. The proximity of the site to local population
centres (i.e. Batchelor and Darwin) means that it is readily accessible to both Aboriginal and
non-Aboriginal people. For short-term visits, residents of Batchelor accessing the site several
times a year for picnics and swimming in the lake are likely to be the more highly exposed
individuals in the population. Aboriginal people from the region were consulted in 2006 and it
was mentioned that the RJCS area is used occasionally for overnight camping and the
collection and consumption of mussels. Consequently, for long-term visits, Aboriginal people
using the site for camping and food gathering activities are likely to be the more highly
exposed individuals in the population as the ingestion of radionuclides in traditional
foodstuffs can contribute significantly to the above background doses received at a
rehabilitated uranium mine site. These persons have thus been selected as Representative
Persons in this assessment. The site access and land use assumptions for these selected
Representative Persons for short- and long-term visits are provided in sections 5.2.1 and
5.2.2, respectively.
The ICRP also recommends that to represent the age range of the population, the radiation
dose to different ages should be considered (ICRP 2006). This is because dose to intake
factors for internal exposure from ingestion and inhalation of radionuclides and effective-toabsorbed dose conversion coefficients for external gamma exposure are age-dependent.
Adults are generally less sensitive to radiation than children (i.e. dose conversion factors
recommended for adults are usually lower than those recommended for children). In this
assessment the dose to two age groups has been considered: an adult and a 10 year old child.
5.2 Site occupancy scenarios
5.2.1 Short-term visits
For short-term visits to RJCS, the following assumptions about site access and land use were
used to assess the dose received from all exposure pathways:

14 short-term visits are made each year

Each short-term visit to the site is for 6 hour duration, from 12:00–18:00 hrs

People remain within the combined picnic area + area 4 for the duration of each visit

Equal amounts of time are spent sitting awake and performing light exercise

No bushfoods are collected and consumed

No water from the lake is consumed.
5.2.2 Long-term visits
For long-term visits to RJCS, the following assumptions about site access were used to assess
the dose received from the external gamma and inhalation pathways:

14 days per year are spent camping and roaming the site

Adults and children sleep for 9 hours each night (21:00–06:00 hrs) in the picnic area

Adults spend 9 hours each day (06:00–15:00 hrs) sitting awake in the picnic area

Adults spend 3 hours each day (15:00–18:00 hrs) roaming the whole site

Adults spend 3 hours each day (18:00–21:00 hrs) performing light exercise in the
picnic area
41

10 year olds spend 3 hours each day (06:00–09:00 hrs) sitting awake in the picnic
area

10 year olds spend 6 hours each day (09:00–12:00 and 18:00–21:00) performing light
exercise in the picnic area

10 year olds spend 6 hours each day (12:00–18:00) roaming the whole site.
It is important to note that changes to the hours spent at certain areas or to the activities
performed will not significantly change the total dose received by adults and children.
Table 12 gives consumed quantities of RJCS bushfoods for adults for long-term visits. It is
assumed that a 10 year old child consumes half the amount of bushfoods eaten by an adult.
Information on consumed quantities of bushfoods has been gleaned from a previous
radiological assessment of the main Rum Jungle site (Bollhöfer et al 2007) for which
information on traditional diet was obtained through consultation with Aboriginal people
living about 25 km downstream of the Rum Jungle site on the Finniss River. The average
bushfood intake for this group (given in Table 12) was similar to estimates previously made
by researchers in the Top End of the Northern Territory (Koperski & Bywater 1985, Johnston
1987, Meehan 1977, Bollhöfer et al 2002) but is most likely an over estimate of bushfoods
sourced and consumed by Aboriginal people accessing RJCS, as there is relatively easy
access to shop bought food and drink in Batchelor.
In this assessment it is assumed that half of the fruits and yams are collected from the picnic
area and half are collected from the whole site. It is also assumed that half of the fish caught
in the lake belong to group 1 and half belong to group 2 (see section 5.5.3). All mussels were
assumed to be sourced from RJCS lake. Goose and cow are assumed to not be hunted and
consumed. While some cattle have been observed on site at RJCS, the animals were from a
nearby cattle station and it is unlikely that they would be hunted by Aboriginal people.
Adults are assumed to drink one litre per day of water collected from the site, with 0.5 litres
taken from the lake and 0.5 litres taken from Meneling Creek. A 10 year old child is assumed
to drink half the water consumed by an adult.
Table 12 Annual bushfood consumption (kg) for an Aboriginal adult living on the east branch of the
Finniss River (from Bollhöfer et al 2007) and assumed 14 day bushfood consumption (kg) for an
Aboriginal adult at RJCS. A 10 year old child is assumed to eat half the amount eaten by an adult.
Food item
Flesh
Organs eaten
Annual consumption
14 day consumption
(Finniss River)
(RJCS)
Wallaby


180
7
Fish


120
4.6
Goose


100
-
Cow

20
-
Turtle

15
0.6
Yams

15
0.6
Pig

10
0.4
Fruit

5
0.2
Crocodile

4
0.15
Mussels

2
1
471
13.8

Total
42
5.3 Dose rates from external gamma radiation
Table 13 gives estimated effective dose rates to an adult and 10 year old child from external
gamma radiation for different areas of the RJCS site and for different physical activities
conducted therein. It also gives background effective dose rates based on the gamma
measurement made at BBFC. The calculated dose rates are for the terrestrial component of
gamma radiation only, with the cosmic component, estimated to be 0.066 µGy h-1 (Marten
1992b), subtracted from the external gamma radiation measurements made in this study.
Conversion factors from air kerma, which is the absorbed dose in air, to effective dose for
terrestrial gamma radiation of 0.69 Sv Gy-1 for adults and 0.79 Sv Gy-1 for children
(UNSCEAR 2000) have been applied.
People sleeping or sitting on the ground (20 cm height) would receive a terrestrial gamma
dose rate that is slightly higher than the dose rate measured at 1 m height due to proximity to
the source. This has been demonstrated both theoretically (Saito & Jacob 1995) and
experimentally (Akber et al 2011). For the purposes of this assessment, a correction factor of
1.2 was applied to the terrestrial gamma dose rates measured at 1 m height in order to
calculate the dose rates to a person sleeping or sitting on the ground. This means that
terrestrial gamma dose rates when sleeping or sitting on the ground have been assumed to be
20% higher than for standing.
The average terrestrial gamma dose rate to a person standing in the combined picnic area +
area 4 was 0.23 µSv h-1 for an adult and 0.27 µSv h-1 for a 10 year old child. The maximum
external gamma dose rate measured in this combined area (1.98 µGy h-1) was under a large
fig tree close to the southeast edge of the overburden heap. The corresponding effective dose
rate from terrestrial gamma radiation to a person standing at this spot was 1.32 µSv h-1 for an
adult and 1.51 µSv h-1 for a child. The average of all external gamma radiation measurements
made across the whole site was 0.79 µGy h-1 (see Table 1). After subtracting the cosmic
component of gamma radiation and applying the conversion factors from above, the resulting
dose rate to a person walking across the whole site was 0.50 µSv h-1 for an adult and 0.57 µSv
h-1 for a child.
Table 13 Effective terrestrial gamma dose rates (µSv h-1) received by an adult and 10 year old child for
various activities on the RJCS site.
Standing/walking (1 m height)
Sleeping (20 cm height)
Picnic area + area 4
Whole site
Background
Picnic area + area 4
Whole site
Background
average
max
average
average
average
max
average
average
Adult
0.23
1.32
0.50
0.037
0.28
1.58
0.60
0.045
10 yr old
0.27
1.51
0.57
0.043
0.32
1.81
0.68
0.051
5.4 Inhalation doses from time spent on site
Table 14 gives the inhalation dose coefficients for RDP and LLAA radionuclides used in this
assessment. The inhalation dose coefficient for RDP has been taken from ICRP Publication
65 (ICRP 1993), which does not provide separate dose coefficients for an adult and 10 year
old child. The inhalation dose coefficient for LLAA radionuclides has been derived from the
nuclide-specific dose from intake factors given in ICRP Publication 72 (ICRP 1996) and from
recommendations on lung solubility types given in ICRP Publication 71 (ICRP 1995).
Inhalation dose is also dependent on breathing rate, which can vary for different levels of
physical activity. Table 15 gives the breathing rate characteristics for an adult and 10 year old
43
child used in this assessment. These are the gender-average of the values given in ICRP
Publication 66 (ICRP 1994).
Table 14 Inhalation dose coefficients for radon decay products (RDP) and long lived alpha activity
(LLAA) used in this assessment.
RDP (µSv m3 µJ-1 h-1)
LLAA (µSv Bqα-1)
Adult
1.1
6.1
10 year old
1.1
7.6
Table 15 Breathing rates (m3 h-1) for a representative adult and 10 year old child for different physical
activities.
Sleeping
Sitting awake
Light exercise
Adult
0.39
0.47
1.38
10 year old
0.31
0.38
1.12
5.4.1 RDP inhalation dose rates
Table 16 gives the absolute fraction of the radon concentration relative to the 24 hour average
for various occupancy times and durations. These fractions have been calculated from the
three-hourly radon concentration measurements made at the picnic area at RJCS on 7–9
September 2011 (see Figure 14).
Table 17 gives the average dose from inhalation of RDP in the combined picnic area + area 4
for various occupancy times and durations. The dose received from time spent in this area for
6 hours during the day (12:00–18:00 hrs) for short-term visits was calculated to be 0.040 µSv
h-1, shown in Table 17 in bold font. Simultaneous RDP concentration measurements made at
RJCS and at BBFC on 7–9 September 2011 indicated that there was little difference in
daytime RDP concentrations between the two sites (Figure 13). The implication is that the
dose received from RDP inhalation from time spent at RJCS for short-term visits during the
day will be similar to the dose received from RDP inhalation from time spent elsewhere in the
region.
Table 18 gives the average dose from RDP inhalation from time spent at RJCS on the whole
site for various occupancy times and durations, taking into account the different area
occupancy assumptions for the long-term visit scenario described in section 5.2.2. The 24
hour average RDP concentration (time weighted) for people camping at RJCS and roaming
the site for three hours in the afternoon (0.612 µJ m-3) was around 7.5 times higher than the
average RDP concentration at BBFC (0.08 µJ m-3). The implication is that the above
background dose received from time spent at RJCS will be approximately 0.59 µSv h -1 on
average during long-term visits.
Table 19 gives the average dose from RDP inhalation from time spent at Batchelor based on
measurements made at BBFC. These values are considered to be representative of the
regional background dose received from RDP inhalation from time spent in natural
(undisturbed) areas.
Doses received from RDP inhalation given in Tables 17, 18 and 19 have been calculated as:
ARadon × (5.56 × 10-3) × E × F × DCF
(3)
Where:
ARadon (Bq m-3) is the average radon concentration in air determined from the TED
measurements (see Table 4)
44
5.56 × 10-3 (µJ m-3 per Bq m-3) is the radon concentration to PAEC conversion factor
E is the equilibrium factor from Table 3
F is the fraction of radon concentration relative to the 24 hour average from Table 16
DCF (µSv m3 µJ-1 h-1) is the RDP inhalation dose coefficient from Table 14
Table 16 Fraction of the radon concentration relative to the 24 hour average for various occupancy
times and durations.
End
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
0
2.33
2.15
2.19
1.71
1.37
1.15
1.01
1.00
0
1.98
2.11
1.50
1.13
0.92
0.79
0.81
0
2.25
1.26
0.85
0.65
0.55
0.62
0
0.27
0.15
0.12
0.13
0.29
0
0.04
0.04
0.09
0.29
0
0.05
0.11
0.38
0
0.17
0.55
0
0.92
Start
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
Table 17 Average dose received (µSv h-1) from RDP inhalation from time spent at RJCS at the
combined picnic area + area 4 for various occupancy times and durations for short-term visits.
End
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
0
1.028
1.067
1.112
1.050
1.028
0.832
0.662
0.595
0
1.086
1.147
1.008
0.935
0.713
0.546
0.499
0
1.206
0.925
0.781
0.544
0.398
0.386
0
0.252
0.169
0.110
0.101
0.187
0
0.046
0.040
0.061
0.169
0
0.029
0.046
0.128
0
0.042
0.116
0
0.059
Start
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
Table 18 Average dose received (µSv h-1) from RDP inhalation from time spent at RJCS for various
occupancy times and durations for long-term visits.
End
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
0
0.621
0.645
0.673
0.635
0.622
0.503
0.400
0.360
0
0.657
0.694
0.610
0.566
0.431
0.330
0.302
0
0.729
0.559
0.472
0.329
0.241
0.234
0
0.152
0.102
0.067
0.061
0.113
0
0.028
0.024
0.037
0.102
0
0.017
0.028
0.078
0
0.026
0.070
0
0.035
Start
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
45
Table 19 Average dose received (µSv h-1) from RDP inhalation from time spent at Batchelor (BBFC) for
various occupancy times and durations.
End
00:00
03:00
06:00
09:00
12:00
15:00
18:00
21:00
24:00
Start
00:00
0
03:00
0.095
0.130
0.162
0.147
0.127
0.112
0.101
0.094
0
0.165
0.195
0.164
0.135
0.115
0.102
0.093
0
0.226
0.164
0.125
0.103
0.089
0.081
0
0.102
0.075
0.062
0.055
0.053
0
0.048
0.042
0.040
0.040
0
0.036
0.035
0.037
0
0.034
0.038
0
0.042
06:00
09:00
12:00
15:00
18:00
21:00
5.4.2 Dose rates from the inhalation of dust-bound LLAA radionuclides
The dose received from dust-bound LLAA radionuclides from time spent in a particular
location can be calculated as:
DCF × LLAA × BR
(4)
Where:
DCF (µSv Bqα-1) is the LLAA inhalation dose coefficient from Table 14
LLAA (Bq m-3) is the concentration of dust-bound LLAA radionuclides in air
BR (m3 h-1) is the breathing rate from Table 15
Table 20 gives the dose received by an adult and child from LLAA radionuclides via the dust
inhalation pathway from time spent at RJCS and at Batchelor, respectively. Values have been
calculated separately for different physical activities (sleeping, sitting and light exercise)
likely to occur during a recreational visit to site. The LLAA radionuclide concentration
measured at RJCS lake on 7–9 September 2011 (0.289 mBq m-3) when the study team
camped at the site has been used in the calculation for RJCS. The time-weighted average
LLAA radionuclide concentration for measurements made from 30 June–7 September 2011
(0.138 mBq m-3) has been used in the calculation for BBFC. The values given in Table 20 for
BBFC are considered to be representative of the regional background dose received by an
adult and 10 year old child from inhalation of dust-bound LLAA radionuclides from time
spent in natural (undisturbed) areas. Based on the values given in Table 20, the dose received
by an adult and child from LLAA radionuclides from time spent at RJCS will be around two
times that from time spent at Batchelor or other natural background sites in the region.
Table 20 Doses received (×10-3 µSv h-1) by an adult and 10 year old child from the dust inhalation
pathway from time spent at RJCS and at Batchelor (BBFC) for different physical activities.
RJCS
Adult
10 year old
BBFC
Adult
10 year old
Sleeping
Sitting
Light exercise
0.68
0.82
2.42
0.68
0.83
2.45
0.33
0.39
1.16
0.32
0.40
1.17
46
5.5 Ingestion doses from consumed quantities of water and bushfoods
To assess the internal dose from the ingestion of radionuclides in food items, the ingested
radionuclide activity needs to be determined and converted to committed effective dose. The
committed effective dose is the sum of the products of the committed organ or tissue
equivalent doses and the appropriate organ or tissue weighting factors (ICRP 1996) and
depends on the integration time in years following intake. The integration time is 50 years for
adults and from intake to age 70 years for children. It is a ‘committed’ dose as the person
ingesting the radionuclide has committed to receive the dose over their lifetime.
Table 21 gives ingestion dose coefficients for the radionuclides considered in this assessment.
These coefficients have been taken from ICRP Publication 72 (ICRP 1996) for an adult and
10 year old child. The dose to intake conversion is generally higher for a 10 year old child
than for an adult as not only is the time committed to receive the dose longer, but also the
absorption of radionuclides in certain tissues is increased in children relative to adults.
Food items (fruit, yam and mussels) were collected on site. No animals were hunted as part of
this study.
Table 21 Ingestion dose coefficients (Sv Bq-1, from ICRP 1996) used in this assessment.
238U
234U
230Th
226Ra
210Pb
210Po
228Ra
228Th
Adult
4.5×10-8
4.9×10-8
2.1×10-7
2.8×10-7
6.9×10-7
1.2×10-6
6.9×10-7
7.2×10-8
10 year old
6.8×10-8
7.4×10-8
2.4×10-7
8.0×10-7
1.9×10-6
2.6×10-6
3.9×10-6
1.5×10-7
5.5.1 Dose from consumed quantities of Lake and Meneling Creek water
Table 22 gives the average radionuclide activity concentrations measured throughout this
study in water from the Lake and in water from Meneling Creek (average for all
measurements plus highest wet season downstream activity concentration measurement). It
also gives the corresponding dose per litre received by an adult and 10 year old child from
radionuclide ingestion from Lake and Meneling Creek water. 210Po and 210Pb are assumed to
be in radioactive equilibrium in the water and thorium activity concentrations are assumed to
be negligible.
Table 22 Radionuclide activity concentrations (mBq l-1) in RJCS lake and Meneling Creek water and
doses received (×10-3 µSv l-1) by an adult and 10 year old child per litre of water consumed.
238U
234U
226Ra
210Pb
210Po
Water concentration
46
46
27
4
4
Adult dose
2.1
2.3
7.5
2.7
4.8
19
10 year old dose
3.1
3.4
21
7.5
10.3
46
Water concentration
6.6
6.6
2.5
1.7
1.7
Adult dose
0.30
0.32
0.71
1.1
2.0
4.5
10 year old dose
0.45
0.49
2.0
3.1
4.3
10
Water concentration
320
320
64
17
17
Adult dose
15
16
18
12
21
81
10 year old dose
22
24
51
33
45
175
Total
RJCS lake
Meneling Creek
Meneling Creek downstream
47
5.5.2 Dose from consumed quantities of freshwater mussels
0.020
0.018
0.016
0.014
0.012
0.010
0.008
0.006
0.004
0.002
0.000
7
Ra-226 [Bq/mussel]
m [kg/mussel]
Figure 23 shows the average wet weight of mussels and the 226Ra, 210Pb and 228Ra loads per
mussel plotted versus the mussel age. Mussel weight increases with age up to 5 years.
Radionuclide loads per mussel increase with age across all mussel age classes.
y = 0.47x + 0.50
R² = 0.46
6
5
4
3
2
1
0
0
5
0
10
5
Ra-228 [Bq/mussel]
Pb-210 [Bq/mussel]
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
10
mussel age [y]
mussel age [y]
y = 0.098x - 0.050
R² = 0.71
0.12
y = 0.0124 - 0.010
R² = 0.84
0.10
0.08
0.06
0.04
0.02
0.00
0
5
0
10
mussel age [y]
5
10
mussel age [y]
Figure 23 Wet weight (kg per mussel) and 226Ra, 210Pb and 228Ra loads (Bq per mussel) plotted versus
mussel age.
The radionuclide loads in mussels of a certain age (Bq per mussel) have been calculated as:
i
jL
= ijC × jd × jm
(5)
Where:
i
jL
is the load (Bq per mussel) of radionuclide i in mussel aged j years
i
jC
is the activity concentration (Bq kg-1 dry weight) of radionuclide i in mussel aged j years
jd
is the ratio of dry weight to wet weight of mussels aged j years
jm
is the average wet weight of mussels aged j years
The ingested activity of a certain radionuclide i depends on the total number of mussels
consumed, the radionuclide loads ijL of mussels of a certain age and the age distribution of the
consumed mussels, and can be calculated using equation (6).
A = n × Σj ijL × jf
i
(6)
Where:
i
A is the activity (Bq) of radionuclide i ingested
jf
is the fraction (0–1) of j year old mussels
n is the total number of mussels consumed
Alternatively, the ingested activity of a certain radionuclide i can be calculated from the
weight of mussels consumed using equation (7).
A = m × Σj ijC × jd × jf
i
(7)
48
Where:
m is the total wet weight (kg) of mussels consumed
i
jC
jd
jf
is the activity concentration (Bq kg-1) of radionuclide i in mussel aged j years
is the ratio of dry weight to wet weight of mussels aged j years
is the fraction (0–1) of j year old mussels
Figure 24 shows the age distribution of the mussels that were collected from RJCS lake close
to the picnic area in December 2010. More than 50 per cent of the mussels collected were in
the age range 0.5–2 years. The total age range of the mussels collected was 0.5–11 years.
0.35
fraction of mussels
fraction of shells
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0.5
1
2
3
4
5
6
7
8
9
10
11
age [yrs]
Figure 24 Age distribution of mussels collected in RJCS in December 2010 (red) and of shells collected
from the lake’s edge close to the picnic area (green). Note that shells were mostly older than 5 years.
During various trips to the site, empty mussel shells were noticed scattered around the edge of
the lake, nearby to disused fire places in the picnic area. As it is likely that people consuming
mussels will pick the larger (older) mussels and throw the smaller (younger) ones back into
the lake, the age distribution of mussels that were consumed was determined from ageing the
empty mussel shells that were collected from around the edge of the lake in May 2011. This
distribution is also shown in Figure 24 and consists mainly of mussels aged 5 years and older.
The weight (and consequently size) of mussels older than 5 years does not change
significantly with age (Figure 23), implying that only mussels of a certain size or greater are
collected for consumption. Consequently, the age fraction of mussels used in equations (6)
and (7) to determine the ingested activity of a radionuclide is equal to the fraction of shells
collected from around the edge of the lake rather than the fraction of mussels collected from
the lake itself.
Table 23 gives radionuclide activity concentrations in mussel flesh sourced from RJCS lake
and dose to an adult and 10 year old child per kilogram of mussel flesh consumed. The dose
per consumed quantity of mussel flesh has been calculated from the radionuclide activity
concentrations and using the ingestion dose coefficients given in Table 21. The radionuclides
that contribute most to the dose received from the consumption of mussel flesh are 226Ra,
210
Pb and 210Po. This is consistent with the findings of other studies made in the Alligator
Rivers Region of doses received from consumption of freshwater mussel (Martin et al 1998,
Ryan et al 2008a).
49
210
Po activity concentration in mussels was not measured in this study. Instead it has been
estimated using the concentration ratio method. Previous studies of radionuclide accumulation
in freshwater mussels indicate that the concentration ratio of 210Po is approximately half that
of 226Ra (Martin 2000, Johnston 1987, Ryan et al 2008a). The concentration ratio for 226Ra
determined for the mussels collected from RJCS lake in December 2010 was 5900 (section
4.5). However, for the purpose of an ingestion dose assessment, a concentration ratio must be
determined that reflects the age distribution of mussels consumed, rather than the age
distribution of those collected from the lake during this study. Thus the concentration ratio for
226
Ra for mussels consumed from RJCS lake has been calculated assuming an age distribution
shown in Figure 24 for the shells collected from the picnic area (green columns). This
concentration ratio was 12,000. An average concentration ratio of 6000 has thus been
assumed for 210Po in the consumed mussels. The average 210Po activity concentration of
mussels consumed from the lake was calculated to 24 Bq kg-1 wet weight.
Table 23 Radionuclide activity concentrations in mussel flesh from RJCS lake (Bq kg-1 wet weight) and
dose to an adult and 10 year old child from consumed quantities of mussel flesh (µSv kg-1).
238U
234U
230Th
226Ra
210Pb
210Po
228Ra
228Th
Bq kg-1
0.94
0.94
0
319
33
24
4.7
3.1
Adult (µSv kg-1)
0.04
0.05
0
89
23
28
3
0.2
144
10 year old (µSv kg-1)
0.06
0.07
0
255
63
62
18
0.5
399
Total
No mussels were found in Meneling Creek by the study team, but in case mussels were
prominent in the creek and consumed by locals, an estimate can be made of radionuclide
activity concentrations in those mussels.
Jeffree & Simpson (1986) and Bollhöfer et al (2011) have shown that uptake of radium in
mussels is reduced by increased calcium and magnesium concentrations in water. Calcium
and magnesium concentrations were generally higher by about a factor of two in Meneling
Creek compared to RJCS water, both during the dry and the wet season (Table 5). Dry season
226Ra and 210Po activity concentrations in Meneling Creek, both upstream and downstream of
the overburden heap, were about 10 and 4 times lower, respectively, than in RJCS lake. Only
the sample collected in January 2011 showed 50% higher water 226Ra activity concentrations
in Meneling Creek downstream and 3 times higher 210Po activity concentrations, respectively.
In April 2011, water 226Ra activity concentration in Meneling Creek downstream was lower
again and about half the concentration in RJCS lake, and 210Po activity concentrations were
similar at the two sites.
During peak wet season conditions from January to March, when almost 1500 mm of rain
was recorded at Batchelor, the ratio [Ra]:[Ca] in water at the downstream site may be similar
to that in RJCS lake, leading to similar uptake of radium (and lead) in the mussels. 210Po
uptake may be similar during that period as well, however, when samples were collected in
April 2011, the [Ra]:[Ca] ratio was 6 times lower downstream than in RJCS lake, and it was
more than 20 times lower during the dry season. It can thus reasonably be assumed that
radionuclide activity concentrations in mussels collected downstream would not exceed the
activity concentrations in mussels from RJCS lake. Consequently, assuming that only mussels
from RJCS lake were consumed is, if anything, conservative.
5.5.3 Dose from consumed quantities of fish, freshwater crocodile and turtle
Fish, crocodile and turtle from the lake have not been sampled as part of this study. However,
the dose received per kilogram of flesh consumed can be estimated using the concentration
50
ratio method and concentration ratios for radionuclide accumulation in fish species, crocodile
and turtle reported by Martin et al (1995, 1998).
Martin et al (1995, 1998) give concentration ratios for two groups of fish. In general,
concentration ratios for group 1 species (Bony bream (Nematalosa erebi) and Sleepy cod
(Oxyeleotris lineolatus)) are higher than those for group 2 species (Catfish (Arius leptaspis,
Plotosidae), Barramundi (Lates clacarifer), Archer fish (Toxotes chatareus), Mullet (Liza
alata), Long tom (Strongylura kreffti), Saratoga (Scleropages jardini) and Tarpon (Megalops
cyprinoides)). Fish from both groups as well as freshwater crocodiles can be found in RJCS
lake (Needham pers comm.), as well as other fish species that are in neither of the two groups
and for which no concentration ratios were available.
Table 24 gives the average radionuclide activity concentrations in RJCS lake water
(unfiltered), concentration ratios (relative to unfiltered water) for group 1 and group 2 fish,
freshwater crocodile and turtle and calculated radionuclide activity concentrations. It also
gives the dose received by an adult and 10 year old child per kilogram of flesh consumed of
these items.
Table 24 Average radionuclide activity concentration in RJCS lake water (unfiltered) (mBq l-1),
concentration ratios (CR, relative to unfiltered water) for group 1 and group 2 fish, freshwater crocodile
and turtle from Martin et al (1995, 1998), calculated flesh radionuclide activity concentrations (Bq kg-1)
and dose received by an adult and child per kg of flesh consumed (µSv kg-1).
238U
234U
230Th
226Ra
210Pb
210Po
mBq l-1 RJCS lake
46
46
0
27
4.0
4.0
CR fish group 1
160
160
15
360
79
790
CR fish group 2
10
10
10
47
20
86
CR freshwater crocodile flesh
6.4
7.4
4.4
46
5.6
710
CR turtle flesh
22
21
32
120
60
460
Total
Bq
kg-1
fish group 1
7.4
7.4
0
9.6
0.31
3.1
Bq
kg-1
fish group 2
0.46
0.46
0
1.3
0.08
0.34
Bq
kg-1
crocodile flesh
0.3
0.34
0
1.2
0.02
2.8
Bq kg-1 turtle flesh
1.0
1.0
0
3.1
0.24
1.8
Adult (µSv kg-1) group 1
0.33
0.36
0
2.7
0.22
3.8
7
10 year old (µSv kg-1) group 1
0.50
0.55
0
7.7
0.60
8.2
17
Adult (µSv kg-1) group 2
0.021
0.023
0
0.35
0.055
0.41
1
10 year old (µSv kg-1) group 2
0.031
0.034
0
1.0
0.15
0.89
2
Adult (µSv
kg-1)
crocodile
0.01
0.02
0
0.34
0.02
3.38
3.8
kg-1)
crocodile 0.02
0.03
0
0.97
0.04
7.32
8.4
turtle
0.05
0.05
0
0.87
0.16
2.21
3.34
0.07
0.07
0
2.48
0.45
4.79
7.86
10 year old (µSv
Adult (µSv
kg-1)
10 year old (µSv kg-1) turtle
5.5.4 Dose from consumed quantities of fruits and yams
Tables 25 and 26 give doses received by an adult and 10 year old per kilogram of flesh
consumed of fruits and yams, respectively, for the RJCS picnic area and whole of site.
Radionuclide activity concentrations measured in fruits and yams as part of this study have
been used by preference to calculate the dose received per kilogram of flesh consumed. The
concentration ratio method has been used where measured data was not available using values
for northern Australian bushfoods reported in Ryan et al (2009). For the calculation of dose
51
received per kilogram of flesh consumed via the concentration ratio method, average soil
226
Ra activity concentration has been calculated from the relationship shown in Figure 9 using
the average external gamma dose rate for the picnic area (0.58 µGy h-1) and whole of site
(0.79 µGy h-1), respectively. Radioactive equilibrium between all uranium decay series
radionuclides in the soils has been assumed.
Table 25 Dose received by an adult and 10 year old child per kg of fruit consumed collected from the
picnic area and whole site. Values calculated via the concentration ratio method are shaded grey. Dry
weight (dw) soil radionuclide activity concentration has been calculated from Figure 9 and assuming
radioactive equilibrium of all uranium decay series radionuclides. Concentration ratios used to calculate
fresh weight (fw) radionuclide activity concentrations in fruit are those reported by Ryan et al (2009).
238U
234U
230Th
226Ra
210Pb
210Po
Total
Picnic area
Soil (Bq kg-1 dw)
888
888
CR (fruit fw / soil dw)
0.005
0.0045
Fruit (Bq kg-1 fw)
Adult (µSv kg-1)
10 year old (µSv
kg-1)
0.87
0.87
4.44
25.68
3.99
3.11
0.04
0.04
0.93
7.2
2.8
3.7
15
0.06
0.07
1.1
2.1
7.6
8.1
37
Whole site
Soil (Bq kg-1 dw)
1209
1209
CR (fruit fw / soil dw)
0.005
0.0045
Fruit (Bq kg-1 fw)
0.50
0.50
6.04
8.77
5.44
1.58
Adult (µSv kg-1)
0.02
0.02
1.3
2.5
3.8
1.9
9.4
10 year old (µSv kg-1)
0.03
0.04
1.5
7.0
10
4.1
23
Table 26 Dose received by an adult and 10 year old child per kg of yam consumed collected from the
picnic area and whole site. Values calculated via the concentration ratio method are shaded grey. Dry
weight (dw) soil radionuclide activity concentration has been calculated from Figure 9 and assuming
radioactive equilibrium of all uranium decay series radionuclides. Concentration ratios used to calculate
fresh weight (fw) radionuclide activity concentrations in yams are those reported by Ryan et al (2009).
238U
234U
230Th
Soil (Bq kg-1 dw)
888
888
CR (fruit fw / soil dw)
0.0029
226Ra
210Pb
210Po
888
888
888
0.0029
0.0082
0.019
0.019
2.57
2.57
7.28
1.48
16.86
16.86
0.12
0.13
1.5
0.41
12
20
34
0.18
0.19
1.7
1.2
32
44
79
Soil (Bq kg-1 dw)
1209
1209
1209
1209
1209
CR (fruit fw / soil dw)
0.0029
0.0029
0.0082
0.019
0.019
Yam (Bq kg-1 fw)
3.51
3.51
9.91
1.48
22.97
22.97
0.16
0.17
2.1
0.41
16
28
46
0.24
0.26
2.4
1.2
44
60
110
Total
Picnic area
Yam (Bq
kg-1
Adult (µSv
fw)
kg-1)
10 year old (µSv
kg-1)
Whole site
Adult (µSv kg-1)
10 year old (µSv
kg-1)
52
5.5.5 Dose from consumed quantities of wallabies and pigs hunted onsite
Wallabies and pigs were not sampled as part of this study. The concentration ratio method has
been used to estimate radionuclide activity concentrations in the flesh of wallabies and pigs
that may forage on site at RJCS from soil radionuclide activity concentrations. The calculated
radionuclide activity concentrations in the flesh of wallabies and pigs were then used to
calculate the dose received by an adult and 10 year old child per kilogram of flesh consumed.
The average soil 226Ra activity concentration across the site (1209 Bq kg-1) has been
calculated from the average of external gamma dose rates in areas 1–6 (0.79 µGy h-1, Table 1)
using the conversion factor of 1530 Bq kg-1 226Ra per µGy h-1 (Figure 9). An average soil
226
Ra activity concentration of 100 Bq kg-1 has been used for environmental background soils,
which is the average of the soil 226Ra activity concentrations measured at RJCS at sampling
points that were unlikely to be affected by historic uranium mining activities. Radioactive
equilibrium between the members of the uranium decay series in soils has been assumed.
Tables 27 and 28 give average soil radionuclide activity concentrations at RJCS (whole site)
and for the environmental background, animal home ranges, radionuclide activity
concentrations in flesh calculated using the concentration ratio method and doses received by
an adult and 10 year old child per kilogram of flesh consumed for wallabies and pigs,
respectively. Home ranges for wallabies and pigs given in the literature were used to estimate
the fraction of time spent on the RJCS site by the animals and thus the flesh radionuclide
activity concentration that could be attributed to radionuclides in the soil at RJCS. A home
range of 1000 ha has been assumed for wild pigs, which is similar to the ranges estimated by
Caley (1997). Because the home range of wild pigs is much larger than the areal extent of the
RJCS site, the contribution to flesh radionuclide activity concentrations from time spent both
on- and offsite was taken into account by calculating area-weighted averages. The home
range for wallabies is much smaller than for pig, generally less than 30 ha (Stirrat 2003). It
was thus assumed that a wallaby’s home range is equivalent in size to the RJCS site and that
the wallaby spends 100% of its time on site. Concentration ratios for pig flesh and for
uranium, 226Ra and 210Po in wallaby were taken from Ryan et al (2009). Wallaby
concentration ratios for 230Th and 210Pb are those found for kangaroo in semi-arid Australian
environments reported by Johansen and Twining (2010).
Table 27 Wallaby: soil radionuclide activity concentrations, concentration ratios, animal home range,
calculated flesh activity concentration and doses received by an adult and 10 year old child per kg of
flesh consumed from RJCS and environmental background areas.
238U
234U
230Th
226Ra
210Pb
210Po
Soil (Bq kg-1) RJCS
1209
1209
1209
1209
1209
1209
Soil (Bq kg-1) bgd
100
100
100
100
100
100
Concentration ratio
0.00004
0.00004
0.0039
0.00008
0.0026
0.013
Home range (ha)
29.1
29.1
29.1
29.1
29.1
29.1
RJCS area (ha)
29.1
29.1
29.1
29.1
29.1
29.1
Flesh (Bq kg-1) RJCS
0.048
0.048
4.7
0.097
3.1
15.7
Flesh (Bq kg-1) bgd
0.004
0.004
0.39
0.008
0.26
1.3
Adult (µSv kg-1) RJCS
2.2×10-3
2.4×10-3
1
2.7×10-2
2.2
19
22
10 yr old (µSv kg-1) RJCS
3.3×10-3
3.6×10-3
1.1
7.7×10-2
6
41
48
Adult (µSv kg-1) bgd
1.8×10-4
2.0×10-4
8.2×10-2
2.2×10-3
0.18
1.6
1.8
-4
-4
-2
-3
0.49
3.4
4
10 yr old (µSv
kg-1)
bgd
2.7×10
3.0×10
9.4×10
53
6.4×10
Total
Table 28 Pig: soil radionuclide activity concentrations, concentration ratios, animal home range,
calculated flesh activity concentration and doses received by an adult and 10 year old child per kg of
flesh consumed from RJCS and environmental background areas.
238U
234U
230Th
226Ra
210Pb
210Po
Soil (Bq kg-1) RJCS
1209
1209
1209
1209
1209
1209
Soil (Bq kg-1) bgd
100
100
100
100
100
100
Concentration ratio
0.00015
0.0001
0.0002
0.00028
0.00014
0.045
Home range (ha)
1000
1000
1000
1000
1000
1000
RJCS area (ha)
29.1
29.1
29.1
29.1
29.1
29.1
Flesh (Bq
kg-1)
RJCS
0.181
0.121
0.242
0.339
0.169
54.4
Flesh (Bq
kg-1)
bgd
0.015
0.010
0.020
0.028
0.014
4.5
Flesh (Bq
kg-1)
combined
0.020
Adult (µSv kg-1) RJCS
0.013
-4
8.9×10
-3
0.026
-4
6.5×10
-4
0.037
-3
5.6×10
-3
0.019
-2
1.0×10
-2
Total
6.0
-2
7
7
-2
1.3×10
10 yr old (µSv kg-1) RJCS
1.3×10
9.8×10
6.3×10
3.0×10
3.5×10
15
16
Adult (µSv kg-1) bgd
6.8×10-4
4.9×10-4
4.2×10-3
7.8×10-3
9.7×10-3
5
5
10 yr old (µSv kg-1) bgd
1.0×10-3
7.4×10-4
4.8×10-3
2.2×10-2
2.7×10-2
12
12
5.6 Dose summary
The Representative Person for short-term visits was selected to be a resident of Batchelor that
accesses the RJCS site on 14 days per year, with each access being for 6 hours (12:00–18:00
hrs). It was assumed that the person would remain within the combined picnic area + area 4
for the duration of each access, using the site for picnics and swimming in the lake, and that
no water or bushfoods were collected and consumed. The only exposure pathways that could
possibly contribute to the dose received by this person are external gamma radiation and
inhalation of RDP and dust-bound LLAA radionuclides. There is zero dose from the ingestion
pathways, but even in the extreme case of a 10 year old child accidentally ingesting 1 litre of
water when swimming in the lake each visit, the ingestion dose would be less than 1 µSv. In
addition to time spent on site, the person would spend the remaining 18 hours of the day in
Batchelor, where they would receive a dose from natural background.
The Representative Person for long-term visits was selected to be an Aboriginal person that
camps at the site for a total of 14 days in a year. It was assumed that the person would spend
most of their time in the vicinity of the picnic area, but would also roam the site to gather
bushfoods for consumption. The exposure pathways that could possibly contribute to the dose
received by this person are external gamma radiation, inhalation of RDP and dust-bound
LLAA radionuclides and ingestion of bushfoods and water.
Table 29 gives estimated daily doses to the public for short- and long-term visits. The
reported doses are total doses received. That is, they are the sum of dose contributions from
time spent on site at RJCS and time spent offsite in environmental background areas.
Radiation levels in environmental background areas have been assumed to be equivalent to
the levels measured at BBFC. The contribution to daily dose for short-term visits was
calculated from 6 hours occupancy at RJCS and 18 hours occupancy in natural background
areas. The contribution to daily dose for long-term visits was calculated for 24 hours
occupancy at RJCS.
54
Table 29 Daily doses (µSv day-1) received by an adult and 10 year old child from short- and long-term
visits to RJCS. The contribution to daily dose for short-term visits was 6 hours from RJCS and 18 hours
from natural background. The contribution to daily dose for long-term visits was 24 hours from RJCS.
Adult
10 yr old
Gamma
RDP (radon)
LLAA (dust)
Ingestion
Total
Short-term
2.2
2.1
0.02
0
4.3
Long-term
7.2
15.3
0.03
24
47
Short-term
2.5
2.1
0.02
0
4.6
Long-term
8.9
12.8
0.04
29
51
Figure 25 shows the daily doses received by an adult and 10 year old child for short- and
long-term visits from terrestrial gamma, inhalation of RDP and inhalation of dust-bound
LLAA radionuclides. Figure 26 shows the contribution to dose from each of these exposure
pathways. For comparative purposes, it also shows the corresponding daily dose that would
be received from these three exposure pathways from natural background.
100
dose [µSv] per 24 hrs
Adult
10
short-term visits
long-term visits
background
1
0.1
0.01
gamma
radon
dust
100
dose [µSv] per 24 hrs
Child
10
short term visits
long term visits
background
1
0.1
0.01
gamma
radon
dust
Figure 25 Daily doses to an adult and child received from terrestrial gamma, RDP and dust inhalation
pathways for short-term visits (6 hours onsite, 18 hours natural background), long-term visits (24 hours
onsite) and typical background conditions (24 hours). Note that graphs are plotted on logarithmic scale
55
30
Adult
dust
radon
gamma
dose [µSv] per 24 hrs
25
20
15
10
5
0
short-term visits
long-term visits
background
30
Child
dust
radon
gamma
dose [µSv] per 24 hrs
25
20
15
10
5
0
short-term visits
long-term visits
background
Figure 26 Daily doses received for short-term visits, long-term visits and typical background conditions,
and contribution from the different pathways
For short-term visits to RJCS during the day the terrestrial gamma pathway is the most
important exposure pathway, contributing around 1.3 µSv day-1 (adult) and 1.5 µSv day-1 (10
year old child) above background. The RDP daily dose for short-term visits between 12:0018:00 hrs is equivalent to the background RDP daily dose and does not make an above
background contribution to dose. This is because radon and RDP are well mixed in daytime
air, with daytime RDP concentrations at RJCS being the same as those at BBFC (Figure 13).
If the site was visited for 6 hours from 9:00 in the morning, the above background radon dose
would contribute an additional 0.5 µSv day-1. The dust inhalation pathway makes negligible
contribution to dose. In the worst case short-term scenario of a person spending 6 hours in the
vicinity of the shady area at the eastern corner of the overburden heap exhibiting the highest
external gamma dose rate (1.98 µGy h-1), the above background dose from gamma radiation
would be 8.5 µSv day-1 (adult) and 9.7 µSv day-1 (child).
For long-term visits to RJCS the gamma and RDP pathways make approximately equal
contributions to total daily dose. The above background contribution from gamma radiation is
6.3 µSv day-1 (adult) and 7.9 µSv day-1 (10 year old child). The above background
contribution from RDP inhalation is 13.1 µSv day-1 (adult) and 10.5 µSv day-1 (10 year old
child). The dust inhalation pathway is around two orders of magnitude lower than other
pathways and makes negligible contribution to dose.
Figures 27 shows the total annual doses received by an adult and 10 year old child for shortand long-term visits from terrestrial gamma, inhalation of RDP and inhalation of dust-bound
LLAA radionuclides. Figure 28 shows the contribution to annual dose from each of these
56
exposure pathways. The total annual dose includes the contributions to dose from time spent
at RJCS (14 days per year at 6 hours per day for short-term visits and 14 days per year at 24
hours per day for long-term visits) and from time spent away from the site from natural
background radiation. Figures 27 and 28 also show the total annual dose that would be
received from these three exposure pathways from natural background radiation alone (i.e. for
a person that resides in Batchelor and does not access RJCS). This background dose amounts
to about 1.2 mSv per year which is typical of the background from terrestrial and airborne
natural radiation (ARPANSA 2011).
It is apparent that for short-term visits the total annual dose received by both an adult and 10
year old child is approximately equal to the annual dose that would be received from natural
background alone. When accessing RJCS for a total of 14 days per year for camping, total
annual doses from external gamma radiation and the inhalation of RDP and dust are
approximately 0.25 mSv per year higher than background both for an adult and 10 year old
child. A theoretical maximum above background dose of 0.6 mSv per year would be received
if people were to camp in the vicinity of the eastern corner of the overburden heap exhibiting
highest external gamma dose rates.
1
dose [µmv] per annum
Adult
0.1
short-term visits
long-term visits
background
0.01
0.001
gamma
radon
dust
1
dose [µmv] per annum
Child
0.1
short-term visits
long-term visits
background
0.01
0.001
gamma
radon
dust
Figure 27 Total annual radiation doses in mSv (including background) received by an adult and 10 year
old child from terrestrial gamma, RDP and dust inhalation pathways for short-term visits (14 visits at 6
hours each), long-term visits (14 days camping on site) and for background conditions at Batchelor
57
2
1.8
Adult
dust
radon
gamma
dose [mSv] per annum
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
short-term visits
2
1.8
Child
long-term visits
dust
radon
background
gamma
dose [mSv] per annum
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
short-term visits
long-term visits
background
Figure 28 Total annual radiation doses (including background) received for short-term visits, long-term
visits and typical background conditions, and contribution from the different pathways
Figure 29 shows the contribution to dose from the ingestion of individual bushfoods and
water, and the contribution to dose from the individual radionuclides. Assuming a diet similar
to that shown in Table 12, mussels collected from the lake and wallaby hunted on site make
approximately equal contributions and together account for around 85% of the total ingestion
dose. Water and other bushfoods, such as group 2 fish, turtle or crocodile, make only small
contributions.
These results are similar to those reported for other sites in the Top End of the Northern
Territory (Ryan et al 2008b; Ryan et al 2009). It is assumed that for consumption of mussels
and wallaby the dose received is entirely above background. This is because: (i) the lake, and
thus the mussels therein, only exist at the site as a consequence of the pit being allowed to fill
with water; and (ii) the home range of the wallaby is restricted to the RJCS site, which has an
average soil activity concentration about 10 times higher than typical background levels
(section 5.5.5). Yams make the largest contribution to dose from plant-derived bushfoods,
contributing around 7% to the total ingestion dose. The total ingestion dose received by an
adult and 10 year old child from consumption of bushfoods and water is approximately
0.4 mSv. 210Po (in wallaby flesh) and 226Ra (in mussels) are the most important radionuclides
from an ingestion dose perspective. The contribution to ingestion dose from uranium isotopes
is negligible.
58
ingestion dose [mSv]
0.35
0.30
Adult
0.25
0.20
0.15
0.10
0.05
0.00
ingestion dose [mSv]
0.35
0.30
Child
0.25
0.20
0.15
0.10
0.05
0.00
ingestion dose [mSv]
0.35
0.30
Adult
0.25
0.20
0.15
0.10
0.05
U-234
Th-230
Ra-226
Pb-210
Po-210
U-234
Th-230
Ra-226
Pb-210
Po-210
U-238
0.00
ingestion dose [mSv]
0.35
0.30
Child
0.25
0.20
0.15
0.10
0.05
U-238
0.00
Figure 29 Modelled ingestion doses received from the various bushfoods and radionuclides for people
camping, hunting and gathering on site for 14 days, for an adult and a child, respectively
59
5.6.1 Case study: The Batchelor Outdoor Education Unit (BOEU)
The Batchelor Outdoor Education Unit is part of the Batchelor Area school. Activities run by
BOEU have been designed for children to raise self-esteem and promote co-operation and are
conducted under the guidance of experienced personnel and instructors. BOEU staff have
been consulted on the use of the Reserve for the activity programmes.
Programmes for school classes run for 4 days each and include one day of access to the Rum
Jungle Lake Reserve for kayaking, canoeing and sailing activities. About 30-40 programmes
are run in a year but each class, and consequently each individual child, is only permitted to
take part in one activity programme per year. Instructors may access the Reserve up to 40
times a year. The site is accessed from about 9:00 am to 2:00 pm, and individual children
spend approximately 2 hours on or in the water where exposure from terrestrial gamma
radiation is negligible. Instructors could spend up to 4.5 hours on the water.
For the purpose of this assessment it is conservatively assumed that six hours (9:00 am to
3:00 pm) are spent by BOEU staff and children in the combined picnic area and area 4 along
the western bank of the Lake (Figure 3) and no time is spent in the water at all. It is assumed
that participants sit for three hours and stand/walk for three hours. Although the participants
in the programme are advised to not drink the lake water it is assumed that 0.5 litre of lake
water is (accidentally) ingested.
Children: The daily above background dose received in the 6 hours spent on site from
terrestrial gamma radiation is about 1.5 µSv (Table 13). The above background doses via the
inhalation pathways are 0.6 µSv from radon decay products (Tables 17 and 19) and 0.005 µSv
from dust (Table 20). The consumption of 0.5 litre of water adds 0.023 µSv (Table 22). Thus
the total above background dose received from one day access to the Rum Jungle Lake
Reserve as part of the BOEU programme for children is 2.1 µSv.
Instructors: The daily above background dose received in the 6 hours spent on site from
terrestrial gamma radiation is about 1.3 µSv (Table 13). The above background doses from
inhalation of radon decay products and dust are 0.6 µSv and 0.006 µSv, respectively. No
water is consumed by adults. Thus the total above background dose received from one day
access to the Rum Jungle Lake Reserve as part of the BOEU programme for instructors is 1.9
µSv. If accessed 40 times in a year the annual above background dose is 75 µSv.
2
dose [mSv] per annum
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Child
BOEU
Child
Background
Instructor
BOEU
Adult
Background
Figure 30 Total annual radiation doses (including background) received by children and instructors
taking part in the BOEU programme, and background doses for children and adults not taking part in the
programme.
60
Figure 30 shows the total annual radiation doses from gamma radiation, radon decay product
and dust inhalation (including background) for an instructor and a child taking part in the
BOEU programme, and a comparison with typical background doses in Batchelor. It is
apparent that there is no significant difference in typical background radiation doses and
doses received by a child accessing the Rum Jungle Lake Reserve when taking part in the
BOEU programme. For instructors accessing the site 40 times a year the annual radiation dose
is approximately 6% higher than their expected typical background radiation dose. Most of
this additional dose is from terrestrial gamma radiation, assuming that the entire time is spent
on the banks of the lake, rather than on the water (however, instructors typically spend up to
75% of the time on the lake, and thus doses are likely overestimated by about a factor of 4).
An increase in the annual radiation dose of a few per cent is of no concern and well within the
natural variability of typical background doses in the Northern Territory, where annual
background gamma radiation doses can vary from less than 0.2 mSv to well above 0.8 mSv
per year (NTGS, 2011).
5.7 Radiation protection context
5.7.1 Existing exposure situation
The current recommendations of the ICRP (ICRP 2007) set out a situation-based approach to
the radiological protection of humans. The recommendations recognise three types of
exposure situation that are intended to cover the entire range of conceivable exposure
circumstances. The three situations are:

Planned exposure situations, which are situations involving the planned introduction
and operation of radiation sources

Emergency exposure situations, which are unexpected situations such as those that
may occur during the operation of a planned situation, or from a malicious act,
requiring urgent attention

Existing exposure situations, which are exposure situations that already exist when a
decision on control has to be taken
Legacy uranium mine sites, such as RJCS, are an example of an existing exposure situation.
For this type of situation the ICRP recommends that reference levels, set typically in the
range 1–20 mSv per year, should be used to restrict individual dose, for example by removing
contaminated material and modifying exposure pathways, or by restricting access and thus
reducing the number of exposed people. The ICRP also recommends that protection should be
optimised such that doses are as low as reasonably achievable (ALARA), taking into account
economic and societal factors. This latter recommendation applies regardless of whether the
assessed doses are above or below the reference level.
This assessment indicates that doses to the public from radiological exposure pathways at
RJCS (external gamma, inhalation and ingestion) are below the general reference level band
of 1–20 mSv per year recommended by the ICRP for existing exposure situations. For 14
short-term visits during the day the average annual doses are approximately 0.02–0.03 mSv
above background (0.075 mSv for 40 days access), with a maximum of a little over 0.1 mSv
above background in the case that most of the time was spent in the close vicinity of the
eastern corner of the overburden heap. For longer term visits, assuming that people camp and
hunt on site for a total of two weeks per year, the annual dose could approach 1 mSv
including the ingestion pathway. The conclusion is that there is currently no unacceptable
radiation risk to people accessing the site for recreational activities.
61
Optimisation of protection (i.e. whether doses are consistent with the ALARA principle,
taking economic and societal factors into account) and whether additional control measures
could be implemented (e.g. locking of the gates at night) to further reduce dose to the public
are issues that could be considered by the regulatory authority. In this context the benefit of a
Reserve in the vicinity of Batchelor for access of the public for recreational activities could be
considered to outweigh the small risk associated with the above background radiation dose
received during access. The benefit, or averted risk, to the public from further reducing the
above background radiation dose associated with the Rum Jungle Lake Reserve would be
very small and resources spent for additional dose control may not be justified in the context
of a cost benefit-analysis of the wider needs of the Coomalie Community. In addition, any
actions that might be considered to reduce doses further should be carefully examined for
their potential to introduce new risks
5.7.2 Anticipated change in radon dose coefficient
The ICRP has recently published a report on lung cancer risk from the inhalation of radon and
radon progeny (ICRP 2010). This report was approved by the ICRP in April 2011, and
published late in 2011. The report also contains a ‘Statement on Radon’, which was published
earlier and approved by the ICRP in November 2009.
The ICRP now recommends that a detriment per unit exposure to radon progeny of 14×10-5
per (mJ h m-3) should be used for quantifying lung cancer risk. This is almost twice as high as
the previous coefficient from ICRP (1993) of 8×10-5 per (mJ h m-3). Furthermore, the ICRP
recommends that doses from the inhalation of radon and RDP should be calculated using
biokinetic and dosimetric models, rather than using the existing dose conversion convention
based on epidemiological studies. This will result in new dose coefficients for the inhalation
of RDP, which will be larger by about a factor of two or more and will be provided by the
ICRP in the near future (ICRP 2010). Until such time as the ICRP publishes new dose
coefficients for the inhalation of RDP, the existing dose coefficient given in Table 14 remains
valid.
The anticipated change in the radon dose coefficient will only have a relatively small effect
on the above background doses received by the public accessing RJCS. The RDP daily dose
for short-term visits will remain equivalent to the background RDP daily dose and not make
an above background contribution. For longer term visits and camping, using the scenario
above, the above background dose will increase by about 0.15–0.18 mSv due to the
anticipated increase in dose received per exposure to radon progeny. This will result in a total
above background dose, including the ingestion pathway, of about 0.8 mSv (compared to 0.6–
0.7 mSv using the current dose coefficient). This still does not present an unacceptable
radiation risk to people accessing the site.
Conclusions and Recommendations
A comprehensive program of environmental sampling and measurement has shown that
radiation levels at RJCS are generally similar to those reported by a previous radiological
investigation done after site rehabilitation in 1990–91. Compared to typical background levels
in the region, the average 24 hr radon decay product concentration during the dry season is
approximately 4 times larger and gamma radiation is about 6 times larger. However, daytime
radon decay product concentrations between 12 pm and 6 pm are similar to background levels
measured at Batchelor, as the air is well mixed during the day with the onset of the southeasterlies. Consequently, the inhalation of radon decay products does not contribute to above
62
background radiation dose when accessing the site during the afternoon. The contribution of
dust to inhalation doses is negligible as well.
Assuming that no bushfoods are harvested on site, the only above background exposure
pathway for afternoon visits is from terrestrial gamma radiation, amounting to approximately
0.0015 mSv per day. If the site was accessed between 9 am and 3 pm the inhalation of radon
decay products contributes an additional 0.0005 mSv per day above background. Instructors
of the BOEU activities programme may receive an above background dose up to 0.075 mSv if
they access the site 40 times per year. Even if the site was accessed every day of the year for
daytime recreational activities, the annual above background dose would be below 1 mSv.
For people accessing the site for camping and food gathering activities for 14 days per year,
terrestrial gamma radiation, radon decay product inhalation and bushfood ingestion are the
most important radiological exposure pathways. Assuming that the majority of food ingested
during those 14 days is hunted (wallaby, pig and fish) and collected (mussels, fruit and yams)
on site, rather than reliance on shop bought food, more than 50 % of the estimated above
background dose originates from the ingestion of bushfoods. The total above background
dose in this case would be 0.046 mSv per day, resulting in an average annual dose above
background of approximately 0.65 mSv. Daily above background doses to people camping on
site but not consuming bushfoods would be approximately 0.02 mSv.
Typically, the doses received for the three scenarios that have been assessed are below the
general reference level band of 1–20 mSv per year recommended by the International
Commission on Radiological Protection for existing exposure situations. The implication is
that at present there is no unacceptable radiation risk to people accessing the site, both for
daytime picnics and for occasional camping and food gathering activities. The anticipated
changes in the radon dose conversion factor are unlikely to change this general conclusion.
However, the site in its present state is not recommended to be used for permanent habitation.
For this occupancy scenario the above background doses would likely approach 20 mSv,
which is at the upper bound of the reference level band recommended by the ICRP. In this
case further remediation of the site or site access restrictions to reduce potential doses would
be needed before habitation could proceed.
Despite the low above background annual radiation doses for the above scenarios, the concept
of optimisation of radiation protection requires the regulator of the site to consider whether
additional control measures could be implemented to further reduce dose to the public. This
should be done in consultation with relevant stakeholders and in the context of a cost-benefit
analysis, bearing in mind that the additional benefit in this case of averted risk from only
slightly above background radiation exposure would be very low. Signage on site currently
states that overnight camping is prohibited. If this restriction was to be enforced and the site
not used for overnight camping, doses to the public would be even lower than what is
presented in this report. Given that gates are already in place at the site, these could be locked
in the evening to prevent night time access by the public and exposure to higher levels of
radon decay products that prevail during the night and in the early morning hours
During early to peak wet season conditions, seepage from the overburden heap is a source of
SO4, major cations, 226Ra and uranium in Meneling Creek, and concentrations were higher
downstream of the overburden heap compared to upstream. In contrast, metal and
radionuclide activity concentrations during the dry season are virtually the same upstream and
downstream. Further investigations may be warranted into the mechanisms of metal
mobilisation and potential acid rock drainage issues from the overburden heap at RJCS.
63
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67
Appendix A Gamma survey instruments and calibration
Table A1 gives details of the instruments used for external gamma radiation measurements.
Table A1 Meter and probe details of instruments used for external gamma radiation measurements.
GM1
GMB
GM3
Description
Environmental dose rate meter
Multi-purpose survey meter
Environmental dose rate meter
Manufacturer
Mini-instruments
Thermo Scientific
Mini-instruments
Model
6-80
RadEye GX
6-80
Serial number
01065
0314
01049
Description
Compensated G-M tube
Compensated G-M tube
Compensated G-M tube
Manufacturer
Mini-instruments
Mini-instruments
Mini-instruments
Model
MC70
MC70
MC70
Serial number
00827
00828
00362
Meter details
Tube details
Instrument GM1 was calibrated against a caesium-137 source of known activity by Australian
Radiation Services on 16 December 2010. Figure A1 shows the relationship between air
kerma rate and count rate from this calibration.
Instruments GMB and GM3 were cross-calibrated against instrument GM1 in the field by
taking parallel measurements of external gamma radiation at four points at the RJCS site with
different gamma signal intensity. Figures A2 and A3 show the relationships between
measured counts for instruments GMB and GM1 and for instruments GM3 and GM1,
respectively. These relationships were used to normalise the measured counts per 60 s from
instruments GMB and GM3 to instrument GM1. The relationship shown in Figure A1 was
then used to determine the absorbed gamma dose rate in air for measurements made with all
instruments.
Figure A1 Relationship between air kerma rate and count rate for instrument GM1, determined from
calibration against a caesium-137 source of known activity
68
Figure A2 Relationship between measured counts for instruments GMB and GM1, determined from infield cross-calibration measurements
Figure A3 Relationship between measured counts for instruments GM3 and GM1, determined from infield cross-calibration measurements
69
Appendix B Dust-bound LLAA radionuclide sampling periods
and results
Table B1 Dust sampling locations, periods between filter changes, sample volumes (m 3) and LLAA
radionuclide concentrations (µBq m-3).
Location
Easting
Northing
Sampling start
Sampling end
Volume
LLAA
RJCS
716742
8557188
30/06/2011 12:25
04/07/2011 10:45
16.9
69 ± 15
04/07/2011 10:45
11/07/2011 14:50
23.5
102 ± 8
11/07/2011 15:08
08/08/2011 14:50
120.9
124 ± 3
08/08/2011 14:50
07/09/2011 09:20
128.6
168 ± 4
(Camp site)
716613
8557211
07/09/2011 09:40
09/09/2011 12:00
9.1
368 ± 16
RJCS downwind
713808
8559132
30/06/2011 13:35
04/07/2011 11:25
16.9
184 ± 14
04/07/2011 11:25
11/07/2011 14:32
30.8
130 ± 9
30/06/2011 11:15
04/07/2011 10:20
17.1
217 ± 14
04/07/2011 10:20
11/07/2011 15:52
31.2
167 ± 13
11/07/2011 15:52
08/08/2011 15:35
117.3
168 ± 3
08/08/2011 15:35
07/09/2011 08:39
128.4
196 ± 4
07/09/2011 08:39
09/09/2011 12:50
9.4
289 ± 21
BBFC
720588
8556249
70
Appendix C Details of water samples
Table C1 Sample number, collection dates and locations for the water samples.
Sample
Collection date
Location
Easting
Northing
RJX10023
25/10/10
Meneling Ck upstream
716252
8556604
RJX10024
25/10/10
Meneling Ck midstream (stagnant)
715982
8556948
RJX10025
25/10/10
Meneling Ck downstream
715868
8557228
RJX10026
25/10/10
Meneling Ck midstream (flowing)
715982
8556948
RJX10027
25/10/10
Lake
716632
8557214
RJX10053
07/12/10
Lake
716641
8557226
RJX11001
14/01/11
Drain SE side of heap
716479
8557050
RJX11002
14/01/11
Lake
716658
8557226
RJX11003
14/01/11
Meneling Ck upstream
716271
8556602
RJX11004
14/01/11
Meneling Ck downstream
715897
8557203
RJX11005
09/03/11
Overflow from lake
716617
8557130
RJX11006
09/03/11
Lake
716640
8557219
RJX11007
09/03/11
Drain SE side of heap
716586
8557154
RJX11008
09/03/11
Drain NW side of heap
716148
8557296
RJS11001
12/04/11
Meneling Ck upstream
716252
8556604
RJS11002
12/04/11
Meneling Ck midstream
715982
8556948
RJS11003
12/04/11
Meneling Ck downstream
715868
8557228
RJS11004
12/04/11
Lake
716631
8557202
RJS11013
31/05/11
Meneling Ck downstream
715868
8557228
RJS11014
31/05/11
Meneling Ck midstream
715982
8556948
RJS11015
31/05/11
Meneling Ck upstream
716252
8556604
RJS11016
31/05/11
Lake
716631
8557202
RJS11048
09/09/11
Meneling Ck upstream
716277
8556615
RJS11049
09/09/11
Meneling Ck downstream
715853
8557248
RJS11050
09/09/11
Lake
716631
8557202
71
Appendix D Gamma survey results
Table D1 Results of gamma survey measurements, including spatial and date/time information,
measured and corrected counts per 60 seconds from each instrument and dose rate. The cosmic
component of external gamma radiation, estimated to be 0.066 µGy h-1 in the Top End of the Northern
Territory (Marten 1992b), has not been subtracted from the results given in the table. [Corrected counts
were determined from the instrument cross-calibration relationships in Appendix A, Figures A2 and A3;
dose rates were determined from the air kerma calibration relationship in Appendix A, Figure A1;
uncertainty in dose rate is one standard deviation based on counting statistics alone].
Easting
Northing
Date and time
Instrument
Measured
counts (60 s)-1
Corrected
counts (60 s)-1
Dose rate
(µGy h-1)
716233
8557612
07/09/2011 10:57
GM 1
216
216
0.20 ± 0.01
716256
8557628
07/09/2011 11:01
GM 1
231
231
0.22 ± 0.01
716282
8557645
07/09/2011 11:03
GM 1
243
243
0.23 ± 0.01
716307
8557660
07/09/2011 11:04
GM 1
287
287
0.27 ± 0.02
716334
8557679
07/09/2011 11:06
GM 1
198
198
0.19 ± 0.01
716360
8557695
07/09/2011 11:08
GM 1
325
325
0.31 ± 0.02
716385
8557717
07/09/2011 11:09
GM 1
254
254
0.24 ± 0.02
716411
8557734
07/09/2011 11:11
GM 1
207
207
0.20 ± 0.01
716436
8557753
07/09/2011 11:13
GM 1
253
253
0.24 ± 0.02
716447
8557763
07/09/2011 11:15
GM 1
240
240
0.23 ± 0.01
716523
8557722
07/09/2011 11:18
GM 1
283
283
0.27 ± 0.02
716502
8557702
07/09/2011 11:24
GM 1
306
306
0.29 ± 0.02
716474
8557683
07/09/2011 11:25
GM 1
247
247
0.23 ± 0.01
716447
8557664
07/09/2011 11:27
GM 1
221
221
0.21 ± 0.01
716420
8557645
07/09/2011 11:29
GM 1
245
245
0.23 ± 0.01
716395
8557625
07/09/2011 11:30
GM 1
313
313
0.30 ± 0.02
716368
8557606
07/09/2011 11:33
GM 1
498
498
0.47 ± 0.02
716342
8557587
07/09/2011 11:34
GM 1
367
367
0.35 ± 0.02
716316
8557566
07/09/2011 11:36
GM 1
392
392
0.37 ± 0.02
716288
8557549
07/09/2011 11:38
GM 1
274
274
0.26 ± 0.02
716256
8557532
07/09/2011 11:41
GM 1
253
253
0.24 ± 0.02
716290
8557448
07/09/2011 11:49
GM 1
338
338
0.32 ± 0.02
716318
8557466
07/09/2011 11:52
GM 1
253
253
0.24 ± 0.02
716345
8557485
07/09/2011 11:53
GM 1
253
253
0.24 ± 0.02
716372
8557507
07/09/2011 11:54
GM 1
277
277
0.26 ± 0.02
716394
8557525
07/09/2011 11:56
GM 1
341
341
0.32 ± 0.02
716420
8557544
07/09/2011 11:59
GM 1
283
283
0.27 ± 0.02
716443
8557564
07/09/2011 12:01
GM 1
350
350
0.33 ± 0.02
716468
8557585
07/09/2011 12:02
GM 1
421
421
0.40 ± 0.02
716495
8557601
07/09/2011 12:04
GM 1
224
224
0.21 ± 0.01
716522
8557620
07/09/2011 12:06
GM 1
266
266
0.25 ± 0.02
716544
8557640
07/09/2011 12:08
GM 1
231
231
0.22 ± 0.01
716569
8557658
07/09/2011 12:09
GM 1
262
262
0.25 ± 0.02
72
716595
8557681
07/09/2011 12:11
GM 1
217
217
0.20 ± 0.01
716608
8557695
07/09/2011 12:12
GM 1
220
220
0.21 ± 0.01
716666
8557624
07/09/2011 12:24
GM 1
383
383
0.36 ± 0.02
716638
8557609
07/09/2011 12:28
GM 1
304
304
0.29 ± 0.02
716612
8557594
07/09/2011 12:30
GM 1
372
372
0.35 ± 0.02
716584
8557578
07/09/2011 12:32
GM 1
397
397
0.37 ± 0.02
716556
8557562
07/09/2011 12:33
GM 1
510
510
0.48 ± 0.02
716526
8557542
07/09/2011 12:36
GM 1
279
279
0.26 ± 0.02
716499
8557524
07/09/2011 12:37
GM 1
246
246
0.23 ± 0.01
716473
8557507
07/09/2011 12:39
GM 1
263
263
0.25 ± 0.02
716445
8557489
07/09/2011 12:40
GM 1
215
215
0.20 ± 0.01
716417
8557466
07/09/2011 12:45
GM 1
290
290
0.27 ± 0.02
716391
8557452
07/09/2011 12:46
GM 1
258
258
0.24 ± 0.02
716362
8557438
07/09/2011 12:48
GM 1
240
240
0.23 ± 0.01
716334
8557423
07/09/2011 12:50
GM 1
512
512
0.48 ± 0.02
716304
8557407
07/09/2011 12:53
GM 1
597
597
0.56 ± 0.02
716276
8557392
07/09/2011 12:54
GM 1
398
398
0.38 ± 0.02
716251
8557378
07/09/2011 12:56
GM 1
410
410
0.39 ± 0.02
716240
8557371
07/09/2011 12:59
GM 1
420
420
0.40 ± 0.02
716226
8557361
07/09/2011 13:02
GM 1
306
306
0.29 ± 0.02
716561
8557517
07/09/2011 14:16
GM 1
474
474
0.45 ± 0.02
716568
8557539
07/09/2011 14:18
GM 1
416
416
0.39 ± 0.02
716536
8557528
07/09/2011 14:20
GM 1
311
311
0.29 ± 0.02
716513
8557507
07/09/2011 14:21
GM 1
252
252
0.24 ± 0.01
716486
8557495
07/09/2011 14:23
GM 1
240
240
0.23 ± 0.01
716466
8557479
07/09/2011 14:24
GM 1
261
261
0.25 ± 0.02
716549
8557448
07/09/2011 14:27
GM 1
360
360
0.34 ± 0.02
716519
8557433
07/09/2011 14:29
GM 1
259
259
0.24 ± 0.02
716566
8557424
07/09/2011 14:30
GM 1
329
329
0.31 ± 0.02
716536
8557410
07/09/2011 14:32
GM 1
256
256
0.24 ± 0.02
716506
8557401
07/09/2011 14:34
GM 1
317
317
0.30 ± 0.02
716504
8557369
07/09/2011 14:36
GM 1
262
262
0.25 ± 0.02
716521
8557371
07/09/2011 14:37
GM 1
272
272
0.26 ± 0.02
716518
8557352
07/09/2011 14:41
GM 1
329
329
0.31 ± 0.02
716536
8557330
07/09/2011 14:43
GM 1
264
264
0.25 ± 0.02
716561
8557311
07/09/2011 14:44
GM 1
295
295
0.28 ± 0.02
716573
8557287
07/09/2011 14:46
GM 1
316
316
0.30 ± 0.02
716582
8557262
07/09/2011 14:48
GM 1
299
299
0.28 ± 0.02
716599
8557236
07/09/2011 14:49
GM 1
350
350
0.33 ± 0.02
716607
8557220
07/09/2011 14:53
GM 1
362
362
0.34 ± 0.02
716624
8557210
07/09/2011 14:55
GM 1
267
267
0.25 ± 0.02
716643
8557201
07/09/2011 14:57
GM 1
224
224
0.21 ± 0.01
73
716625
8557197
07/09/2011 14:58
GM 1
411
411
0.39 ± 0.02
716603
8557191
07/09/2011 15:00
GM 1
934
934
0.88 ± 0.03
716609
8557174
07/09/2011 15:01
GM 1
841
841
0.79 ± 0.03
716628
8557171
07/09/2011 15:03
GM 1
391
391
0.37 ± 0.02
716618
8557164
07/09/2011 15:06
GM 1
531
531
0.50 ± 0.02
716601
8557149
07/09/2011 15:07
GM 1
634
634
0.60 ± 0.02
716592
8557133
07/09/2011 15:09
GM 1
669
669
0.63 ± 0.02
716609
8557136
07/09/2011 15:13
GM 1
470
470
0.44 ± 0.02
716621
8557146
07/09/2011 15:15
GM 1
406
406
0.38 ± 0.02
716639
8557157
07/09/2011 15:17
GM 1
408
408
0.38 ± 0.02
716652
8557165
07/09/2011 15:18
GM 1
325
325
0.31 ± 0.02
716690
8557098
07/09/2011 15:23
GM 1
244
244
0.23 ± 0.01
716666
8557087
07/09/2011 15:25
GM 1
222
222
0.21 ± 0.01
716642
8557080
07/09/2011 15:27
GM 1
297
297
0.28 ± 0.02
716616
8557071
07/09/2011 15:28
GM 1
342
342
0.32 ± 0.02
716594
8557052
07/09/2011 15:30
GM 1
332
332
0.31 ± 0.02
716542
8557074
07/09/2011 15:34
GM 1
751
751
0.71 ± 0.03
716523
8557096
07/09/2011 15:35
GM 1
3696
3696
3.49 ± 0.06
716506
8557083
07/09/2011 15:37
GM 1
1651
1651
1.56 ± 0.04
716627
8557042
07/09/2011 15:41
GM 1
311
311
0.29 ± 0.02
716646
8557062
07/09/2011 15:42
GM 1
291
291
0.27 ± 0.02
716664
8557084
07/09/2011 15:44
GM 1
260
260
0.25 ± 0.02
716681
8557104
07/09/2011 15:46
GM 1
230
230
0.22 ± 0.01
716696
8557115
07/09/2011 15:47
GM 1
345
345
0.33 ± 0.02
716682
8557149
07/09/2011 16:00
GM 1
382
382
0.36 ± 0.02
716701
8557146
07/09/2011 16:01
GM 1
391
391
0.37 ± 0.02
716720
8557143
07/09/2011 16:02
GM 1
380
380
0.36 ± 0.02
716742
8557135
07/09/2011 16:04
GM 1
380
380
0.36 ± 0.02
716726
8557120
07/09/2011 16:06
GM 1
415
415
0.39 ± 0.02
716715
8557105
07/09/2011 16:07
GM 1
342
342
0.32 ± 0.02
716555
8557134
08/09/2011 07:50
GM 1
5409
5409
5.10 ± 0.07
716560
8557156
08/09/2011 07:53
GM 1
4675
4675
4.41 ± 0.06
716568
8557171
08/09/2011 07:56
GM 1
2979
2979
2.81 ± 0.05
716564
8557188
08/09/2011 07:58
GM 1
2580
2580
2.43 ± 0.05
716556
8557206
08/09/2011 08:01
GM 1
2148
2148
2.03 ± 0.04
716546
8557222
08/09/2011 08:02
GM 1
817
817
0.77 ± 0.03
716533
8557245
08/09/2011 08:04
GM 1
405
405
0.38 ± 0.02
716523
8557258
08/09/2011 08:06
GM 1
883
883
0.83 ± 0.03
716514
8557278
08/09/2011 08:08
GM 1
590
590
0.56 ± 0.02
716507
8557299
08/09/2011 08:10
GM 1
605
605
0.57 ± 0.02
716499
8557321
08/09/2011 08:12
GM 1
617
617
0.58 ± 0.02
716486
8557343
08/09/2011 08:14
GM 1
484
484
0.46 ± 0.02
74
716476
8557362
08/09/2011 08:16
GM 1
694
694
0.65 ± 0.02
716468
8557378
08/09/2011 08:18
GM 1
547
547
0.52 ± 0.02
716462
8557388
08/09/2011 08:20
GM 1
508
508
0.48 ± 0.02
716449
8557402
08/09/2011 08:21
GM 1
624
624
0.59 ± 0.02
716381
8557398
08/09/2011 08:26
GM 1
505
505
0.48 ± 0.02
716392
8557380
08/09/2011 08:29
GM 1
641
641
0.60 ± 0.02
716403
8557362
08/09/2011 08:31
GM 1
1207
1207
1.14 ± 0.03
716413
8557349
08/09/2011 08:33
GM 1
1088
1088
1.03 ± 0.03
716422
8557333
08/09/2011 08:35
GM 1
1936
1936
1.83 ± 0.04
716434
8557315
08/09/2011 08:37
GM 1
383
383
0.36 ± 0.02
716447
8557291
08/09/2011 08:39
GM 1
495
495
0.47 ± 0.02
716458
8557275
08/09/2011 08:47
GM 1
385
385
0.36 ± 0.02
716469
8557258
08/09/2011 08:49
GM 1
433
433
0.41 ± 0.02
716479
8557239
08/09/2011 08:51
GM 1
481
481
0.45 ± 0.02
716485
8557219
08/09/2011 08:53
GM 1
394
394
0.37 ± 0.02
716492
8557199
08/09/2011 08:55
GM 1
308
308
0.29 ± 0.02
716499
8557182
08/09/2011 08:57
GM 1
797
797
0.75 ± 0.03
716509
8557159
08/09/2011 09:01
GM 1
1648
1648
1.55 ± 0.04
716510
8557146
08/09/2011 09:03
GM 1
4123
4123
3.89 ± 0.06
716501
8557132
08/09/2011 09:05
GM 1
2407
2407
2.27 ± 0.05
716504
8557121
08/09/2011 09:07
GM 1
3503
3503
3.30 ± 0.06
716509
8557111
08/09/2011 09:09
GM 1
3681
3681
3.47 ± 0.06
716515
8557100
08/09/2011 09:11
GM 1
2831
2831
2.67 ± 0.05
716476
8557053
08/09/2011 09:26
GM 1
1888
1888
1.78 ± 0.04
716470
8557073
08/09/2011 09:29
GM 1
1397
1397
1.32 ± 0.04
716470
8557094
08/09/2011 09:31
GM 1
1707
1707
1.61 ± 0.04
716462
8557118
08/09/2011 09:34
GM 1
1156
1156
1.09 ± 0.03
716458
8557133
08/09/2011 09:36
GM 1
1195
1195
1.13 ± 0.03
716456
8557153
08/09/2011 09:38
GM 1
723
723
0.68 ± 0.03
716449
8557170
08/09/2011 09:42
GM 1
406
406
0.38 ± 0.02
716441
8557187
08/09/2011 09:44
GM 1
257
257
0.24 ± 0.02
716435
8557202
08/09/2011 09:46
GM 1
350
350
0.33 ± 0.02
716428
8557218
08/09/2011 09:49
GM 1
650
650
0.61 ± 0.02
716420
8557232
08/09/2011 09:51
GM 1
557
557
0.53 ± 0.02
716410
8557249
08/09/2011 09:53
GM 1
311
311
0.29 ± 0.02
716398
8557264
08/09/2011 09:54
GM 1
291
291
0.27 ± 0.02
716387
8557280
08/09/2011 09:56
GM 1
276
276
0.26 ± 0.02
716376
8557295
08/09/2011 09:58
GM 1
1185
1185
1.12 ± 0.03
716370
8557307
08/09/2011 10:00
GM 1
1338
1338
1.26 ± 0.03
716363
8557318
08/09/2011 10:02
GM 1
1232
1232
1.16 ± 0.03
716357
8557327
08/09/2011 10:04
GM 1
1342
1342
1.27 ± 0.03
716346
8557337
08/09/2011 10:05
GM 1
1206
1206
1.14 ± 0.03
75
716340
8557344
08/09/2011 10:07
GM 1
701
701
0.66 ± 0.02
716333
8557352
08/09/2011 10:09
GM 1
874
874
0.82 ± 0.03
716324
8557369
08/09/2011 10:11
GM 1
474
474
0.45 ± 0.02
716275
8557342
08/09/2011 10:14
GM 1
450
450
0.42 ± 0.02
716288
8557326
08/09/2011 10:16
GM 1
552
552
0.52 ± 0.02
716295
8557312
08/09/2011 10:18
GM 1
600
600
0.57 ± 0.02
716305
8557299
08/09/2011 10:20
GM 1
906
906
0.85 ± 0.03
716310
8557283
08/09/2011 10:22
GM 1
915
915
0.86 ± 0.03
716318
8557271
08/09/2011 10:25
GM 1
493
493
0.47 ± 0.02
716331
8557258
08/09/2011 10:26
GM 1
1097
1097
1.03 ± 0.03
716343
8557246
08/09/2011 10:28
GM 1
362
362
0.34 ± 0.02
716352
8557231
08/09/2011 10:31
GM 1
585
585
0.55 ± 0.02
716362
8557217
08/09/2011 10:33
GM 1
1224
1224
1.15 ± 0.03
716369
8557200
08/09/2011 10:35
GM 1
721
721
0.68 ± 0.03
716380
8557181
08/09/2011 10:37
GM 1
871
871
0.82 ± 0.03
716389
8557162
08/09/2011 10:38
GM 1
2226
2226
2.10 ± 0.04
716396
8557140
08/09/2011 10:40
GM 1
2184
2184
2.06 ± 0.04
716406
8557122
08/09/2011 10:42
GM 1
682
682
0.64 ± 0.02
716415
8557107
08/09/2011 10:45
GM 1
1824
1824
1.72 ± 0.04
716419
8557096
08/09/2011 10:47
GM 1
2037
2037
1.92 ± 0.04
716423
8557084
08/09/2011 10:49
GM 1
1275
1275
1.20 ± 0.03
716427
8557073
08/09/2011 10:52
GM 1
1598
1598
1.51 ± 0.04
716433
8557059
08/09/2011 10:54
GM 1
1398
1398
1.32 ± 0.04
716434
8557042
08/09/2011 10:55
GM 1
1167
1167
1.1 0± 0.03
716439
8557030
08/09/2011 10:57
GM 1
2203
2203
2.08 ± 0.04
716445
8557020
08/09/2011 10:59
GM 1
1378
1378
1.30 ± 0.04
716448
8557005
08/09/2011 11:02
GM 1
1778
1778
1.68 ± 0.04
716454
8556992
08/09/2011 11:03
GM 1
1113
1113
1.05 ± 0.03
716416
8556935
08/09/2011 11:38
GM 1
689
689
0.65 ± 0.02
716411
8556959
08/09/2011 11:40
GM 1
832
832
0.78 ± 0.03
716408
8556974
08/09/2011 11:42
GM 1
712
712
0.67 ± 0.03
716403
8556992
08/09/2011 11:44
GM 1
1210
1210
1.14 ± 0.03
716398
8557004
08/09/2011 11:46
GM 1
1381
1381
1.30 ± 0.04
716394
8557018
08/09/2011 11:48
GM 1
1037
1037
0.98 ± 0.03
716388
8557034
08/09/2011 11:51
GM 1
997
997
0.94 ± 0.03
716381
8557050
08/09/2011 11:52
GM 1
906
906
0.85 ± 0.03
716377
8557064
08/09/2011 11:54
GM 1
1148
1148
1.08 ± 0.03
716368
8557080
08/09/2011 11:56
GM 1
920
920
0.87 ± 0.03
716357
8557100
08/09/2011 11:58
GM 1
1108
1108
1.05 ± 0.03
716349
8557119
08/09/2011 12:00
GM 1
841
841
0.79 ± 0.03
716337
8557137
08/09/2011 12:01
GM 1
501
501
0.47 ± 0.02
716327
8557154
08/09/2011 12:03
GM 1
324
324
0.31 ± 0.02
76
716318
8557169
08/09/2011 12:05
GM 1
297
297
0.28 ± 0.02
716311
8557185
08/09/2011 12:07
GM 1
378
378
0.36 ± 0.02
716298
8557202
08/09/2011 12:09
GM 1
657
657
0.62 ± 0.02
716285
8557220
08/09/2011 12:10
GM 1
880
880
0.83 ± 0.03
716278
8557232
08/09/2011 12:12
GM 1
1531
1531
1.44 ± 0.04
716272
8557247
08/09/2011 12:15
GM 1
1170
1170
1.10 ± 0.03
716271
8557262
08/09/2011 12:17
GM 1
890
890
0.84 ± 0.03
716254
8557271
08/09/2011 12:19
GM 1
774
774
0.73 ± 0.03
716250
8557281
08/09/2011 12:21
GM 1
896
896
0.85 ± 0.03
716244
8557295
08/09/2011 12:23
GM 1
959
959
0.90 ± 0.03
716235
8557310
08/09/2011 12:24
GM 1
887
887
0.84 ± 0.03
716228
8557328
08/09/2011 12:26
GM 1
597
597
0.56 ± 0.02
716174
8557302
08/09/2011 12:34
GM 1
941
941
0.89 ± 0.03
716185
8557285
08/09/2011 12:35
GM 1
2254
2254
2.13 ± 0.04
716192
8557274
08/09/2011 12:38
GM 1
1347
1347
1.27 ± 0.03
716202
8557261
08/09/2011 12:39
GM 1
1080
1080
1.02 ± 0.03
716212
8557241
08/09/2011 12:41
GM 1
740
740
0.70 ± 0.03
716222
8557223
08/09/2011 12:43
GM 1
877
877
0.83 ± 0.03
716230
8557206
08/09/2011 12:44
GM 1
972
972
0.92 ± 0.03
716239
8557190
08/09/2011 12:47
GM 1
1040
1040
0.98 ± 0.03
716247
8557174
08/09/2011 12:48
GM 1
907
907
0.86 ± 0.03
716258
8557160
08/09/2011 12:51
GM 1
1686
1686
1.59 ± 0.04
716266
8557145
08/09/2011 12:53
GM 1
877
877
0.83 ± 0.03
716276
8557131
08/09/2011 12:54
GM 1
636
636
0.60 ± 0.02
716287
8557119
08/09/2011 12:57
GM 1
640
640
0.60 ± 0.02
716297
8557102
08/09/2011 12:58
GM 1
614
614
0.58 ± 0.02
716306
8557089
08/09/2011 13:00
GM 1
891
891
0.84 ± 0.03
716313
8557074
08/09/2011 13:01
GM 1
1074
1074
1.01 ± 0.03
716326
8557061
08/09/2011 13:04
GM 1
699
699
0.66 ± 0.02
716332
8557043
08/09/2011 13:05
GM 1
627
627
0.59 ± 0.02
716338
8557033
08/09/2011 13:08
GM 1
693
693
0.65 ± 0.02
716342
8557022
08/09/2011 13:10
GM 1
992
992
0.94 ± 0.03
716345
8557010
08/09/2011 13:12
GM 1
1437
1437
1.36 ± 0.04
716346
8556998
08/09/2011 13:13
GM 1
1385
1385
1.31 ± 0.04
716349
8556974
08/09/2011 13:15
GM 1
346
346
0.33 ± 0.02
716352
8556953
08/09/2011 13:17
GM 1
555
555
0.52 ± 0.02
716358
8556933
08/09/2011 13:19
GM 1
984
984
0.93 ± 0.03
716365
8556914
08/09/2011 13:21
GM 1
288
288
0.27 ± 0.02
716373
8556899
08/09/2011 13:23
GM 1
344
344
0.32 ± 0.02
716303
8556938
08/09/2011 15:02
GM 1
315
315
0.30 ± 0.02
716298
8556956
08/09/2011 15:04
GM 1
301
301
0.28 ± 0.02
716297
8556976
08/09/2011 15:06
GM 1
686
686
0.65 ± 0.02
77
716290
8556992
08/09/2011 15:07
GM 1
465
465
0.44 ± 0.02
716280
8557010
08/09/2011 15:09
GM 1
803
803
0.76 ± 0.03
716271
8557026
08/09/2011 15:10
GM 1
1316
1316
1.24 ± 0.03
716260
8557039
08/09/2011 15:12
GM 1
1189
1189
1.12 ± 0.03
716251
8557052
08/09/2011 15:14
GM 1
940
940
0.89 ± 0.03
716240
8557062
08/09/2011 15:15
GM 1
1006
1006
0.95 ± 0.03
716230
8557074
08/09/2011 15:18
GM 1
1005
1005
0.95 ± 0.03
716217
8557083
08/09/2011 15:20
GM 1
1037
1037
0.98 ± 0.03
716208
8557096
08/09/2011 15:22
GM 1
1100
1100
1.04 ± 0.03
716192
8557115
08/09/2011 15:23
GM 1
1067
1067
1.01 ± 0.03
716183
8557134
08/09/2011 15:25
GM 1
1171
1171
1.10 ± 0.03
716176
8557153
08/09/2011 15:27
GM 1
1287
1287
1.21 ± 0.03
716171
8557171
08/09/2011 15:29
GM 1
1121
1121
1.06 ± 0.03
716163
8557188
08/09/2011 15:31
GM 1
1887
1887
1.78 ± 0.04
716156
8557204
08/09/2011 15:33
GM 1
1928
1928
1.82 ± 0.04
716150
8557219
08/09/2011 15:35
GM 1
1120
1120
1.06 ± 0.03
716144
8557237
08/09/2011 15:37
GM 1
1123
1123
1.06 ± 0.03
716126
8557247
08/09/2011 15:39
GM 1
493
493
0.47 ± 0.02
716122
8557224
08/09/2011 15:43
GM 1
740
740
0.70 ± 0.03
716124
8557204
08/09/2011 15:45
GM 1
744
744
0.70 ± 0.03
716131
8557183
08/09/2011 15:46
GM 1
1007
1007
0.95 ± 0.03
716138
8557162
08/09/2011 15:48
GM 1
1009
1009
0.95 ± 0.03
716144
8557141
08/09/2011 15:50
GM 1
1310
1310
1.24 ± 0.03
716153
8557120
08/09/2011 15:52
GM 1
1112
1112
1.05 ± 0.03
716164
8557102
08/09/2011 15:53
GM 1
914
914
0.86 ± 0.03
716180
8557084
08/09/2011 15:56
GM 1
648
648
0.61 ± 0.02
716192
8557066
08/09/2011 15:58
GM 1
496
496
0.47 ± 0.02
716205
8557047
08/09/2011 16:00
GM 1
413
413
0.39 ± 0.02
716218
8557028
08/09/2011 16:02
GM 1
399
399
0.38 ± 0.02
716233
8557010
08/09/2011 16:03
GM 1
432
432
0.41 ± 0.02
716244
8556993
08/09/2011 16:05
GM 1
678
678
0.64 ± 0.02
716255
8556978
08/09/2011 16:07
GM 1
338
338
0.32 ± 0.02
716265
8556957
08/09/2011 16:09
GM 1
218
218
0.21 ± 0.01
716230
8556949
08/09/2011 16:14
GM 1
209
209
0.20 ± 0.01
716212
8556969
08/09/2011 16:15
GM 1
385
385
0.36 ± 0.02
716189
8556989
08/09/2011 16:18
GM 1
474
474
0.45 ± 0.02
716177
8557010
08/09/2011 16:20
GM 1
221
221
0.21 ± 0.01
716170
8557036
08/09/2011 16:22
GM 1
214
214
0.20 ± 0.01
716156
8557064
08/09/2011 16:25
GM 1
537
537
0.51 ± 0.02
716127
8557086
08/09/2011 16:28
GM 1
943
943
0.89 ± 0.03
716114
8557113
08/09/2011 16:30
GM 1
1029
1029
0.97 ± 0.03
716097
8557139
08/09/2011 16:31
GM 1
620
620
0.58 ± 0.02
78
716223
8557646
07/09/2011 10:57
GM 3
190
202
0.19 ± 0.01
716243
8557657
07/09/2011 11:02
GM 3
185
197
0.19 ± 0.01
716273
8557678
07/09/2011 11:04
GM 3
203
216
0.20 ± 0.01
716297
8557696
07/09/2011 11:07
GM 3
502
534
0.50 ± 0.02
716349
8557739
07/09/2011 11:11
GM 3
370
393
0.37 ± 0.02
716349
8557738
07/09/2011 11:11
GM 3
298
317
0.30 ± 0.02
716375
8557757
07/09/2011 11:13
GM 3
266
283
0.27 ± 0.02
716402
8557774
07/09/2011 11:15
GM 3
224
238
0.22 ± 0.01
716427
8557791
07/09/2011 11:17
GM 3
170
181
0.17 ± 0.01
716500
8557744
07/09/2011 11:26
GM 3
379
403
0.38 ± 0.02
716479
8557720
07/09/2011 11:28
GM 3
218
232
0.22 ± 0.01
716451
8557700
07/09/2011 11:30
GM 3
211
224
0.21 ± 0.01
716425
8557681
07/09/2011 11:32
GM 3
197
209
0.20 ± 0.01
716398
8557659
07/09/2011 11:34
GM 3
296
315
0.30 ± 0.02
716374
8557638
07/09/2011 11:36
GM 3
255
271
0.26 ± 0.02
716345
8557620
07/09/2011 11:38
GM 3
425
452
0.43 ± 0.02
716317
8557600
07/09/2011 11:40
GM 3
410
436
0.41 ± 0.02
716288
8557579
07/09/2011 11:42
GM 3
239
254
0.24 ± 0.02
716261
8557563
07/09/2011 11:44
GM 3
235
250
0.24 ± 0.01
716252
8557559
07/09/2011 11:46
GM 3
230
245
0.23 ± 0.01
716286
8557488
07/09/2011 11:51
GM 3
296
315
0.30 ± 0.02
716314
8557506
07/09/2011 11:53
GM 3
290
308
0.29 ± 0.02
716342
8557523
07/09/2011 11:55
GM 3
469
499
0.47 ± 0.02
716370
8557540
07/09/2011 11:57
GM 3
384
408
0.39 ± 0.02
716397
8557558
07/09/2011 11:59
GM 3
314
334
0.31 ± 0.02
716423
8557581
07/09/2011 12:01
GM 3
247
263
0.25 ± 0.02
716449
8557601
07/09/2011 12:04
GM 3
342
364
0.34 ± 0.02
716474
8557623
07/09/2011 12:05
GM 3
307
326
0.31 ± 0.02
716501
8557643
07/09/2011 12:07
GM 3
243
258
0.24 ± 0.02
716527
8557665
07/09/2011 12:09
GM 3
225
239
0.23 ± 0.01
716551
8557687
07/09/2011 12:11
GM 3
197
209
0.20 ± 0.01
716576
8557707
07/09/2011 12:13
GM 3
211
224
0.21 ± 0.01
716587
8557718
07/09/2011 12:15
GM 3
170
181
0.17 ± 0.01
716649
8557656
07/09/2011 12:24
GM 3
267
284
0.27 ± 0.02
716620
8557640
07/09/2011 12:28
GM 3
298
317
0.30 ± 0.02
716595
8557621
07/09/2011 12:30
GM 3
407
433
0.41 ± 0.02
716571
8557604
07/09/2011 12:32
GM 3
249
265
0.25 ± 0.02
716542
8557589
07/09/2011 12:34
GM 3
227
241
0.23 ± 0.01
716511
8557569
07/09/2011 12:35
GM 3
248
264
0.25 ± 0.02
716487
8557550
07/09/2011 12:37
GM 3
232
247
0.23 ± 0.01
716458
8557533
07/09/2011 12:39
GM 3
421
448
0.42 ± 0.02
716433
8557515
07/09/2011 12:41
GM 3
221
235
0.22 ± 0.01
79
716403
8557498
07/09/2011 12:42
GM 3
228
242
0.23 ± 0.01
716373
8557482
07/09/2011 12:44
GM 3
202
215
0.20 ± 0.01
716347
8557462
07/09/2011 12:47
GM 3
236
251
0.24 ± 0.01
716314
8557445
07/09/2011 12:49
GM 3
337
358
0.34 ± 0.02
716286
8557428
07/09/2011 12:51
GM 3
295
314
0.30 ± 0.02
716258
8557411
07/09/2011 12:53
GM 3
1118
1189
1.12 ± 0.03
716247
8557409
07/09/2011 12:55
GM 3
1162
1236
1.17 ± 0.03
716228
8557401
07/09/2011 12:57
GM 3
1421
1511
1.43 ± 0.04
716210
8557394
07/09/2011 12:59
GM 3
1393
1481
1.40 ± 0.04
716554
8557475
07/09/2011 14:16
GM 3
348
370
0.35 ± 0.02
716528
8557463
07/09/2011 14:22
GM 3
239
254
0.24 ± 0.02
716498
8557449
07/09/2011 14:23
GM 3
256
272
0.26 ± 0.02
716469
8557435
07/09/2011 14:25
GM 3
608
647
0.61 ± 0.02
716439
8557418
07/09/2011 14:26
GM 3
359
382
0.36 ± 0.02
716432
8557414
07/09/2011 14:28
GM 3
699
743
0.70 ± 0.03
716462
8557416
07/09/2011 14:30
GM 3
469
499
0.47 ± 0.02
716484
8557398
07/09/2011 14:31
GM 3
351
373
0.35 ± 0.02
716564
8557402
07/09/2011 14:34
GM 3
296
315
0.30 ± 0.02
716542
8557397
07/09/2011 14:36
GM 3
335
356
0.34 ± 0.02
716506
8557355
07/09/2011 14:41
GM 3
430
457
0.43 ± 0.02
716520
8557328
07/09/2011 14:43
GM 3
341
363
0.34 ± 0.02
716535
8557307
07/09/2011 14:45
GM 3
331
352
0.33 ± 0.02
716548
8557283
07/09/2011 14:47
GM 3
436
464
0.44 ± 0.02
716561
8557256
07/09/2011 14:49
GM 3
510
542
0.51 ± 0.02
716576
8557231
07/09/2011 14:51
GM 3
662
704
0.66 ± 0.03
716585
8557218
07/09/2011 14:54
GM 3
1038
1104
1.04 ± 0.03
716589
8557201
07/09/2011 14:56
GM 3
1972
2097
1.98 ± 0.04
716594
8557185
07/09/2011 14:58
GM 3
1343
1428
1.35 ± 0.04
716587
8557164
07/09/2011 15:00
GM 3
1714
1823
1.72 ± 0.04
716579
8557146
07/09/2011 15:01
GM 3
2525
2685
2.53 ± 0.05
716568
8557128
07/09/2011 15:04
GM 3
2168
2305
2.17 ± 0.05
716551
8557117
07/09/2011 15:06
GM 3
1727
1836
1.73 ± 0.04
716562
8557101
07/09/2011 15:07
GM 3
1018
1083
1.02 ± 0.03
716577
8557111
07/09/2011 15:09
GM 3
1024
1089
1.03 ± 0.03
716595
8557120
07/09/2011 15:11
GM 3
415
441
0.42 ± 0.02
716618
8557131
07/09/2011 15:14
GM 3
446
474
0.45 ± 0.02
716637
8557135
07/09/2011 15:15
GM 3
384
408
0.39 ± 0.02
716657
8557140
07/09/2011 15:17
GM 3
314
334
0.31 ± 0.02
716668
8557154
07/09/2011 15:19
GM 3
381
405
0.38 ± 0.02
716682
8557134
07/09/2011 15:23
GM 3
316
336
0.32 ± 0.02
716656
8557118
07/09/2011 15:25
GM 3
210
223
0.21 ± 0.01
716633
8557105
07/09/2011 15:27
GM 3
268
285
0.27 ± 0.02
80
716609
8557089
07/09/2011 15:29
GM 3
469
499
0.47 ± 0.02
716585
8557073
07/09/2011 15:31
GM 3
925
984
0.93 ± 0.03
716563
8557059
07/09/2011 15:32
GM 3
1210
1287
1.21 ± 0.03
716529
8557062
07/09/2011 15:34
GM 3
503
535
0.50 ± 0.02
716500
8557070
07/09/2011 15:36
GM 3
1057
1124
1.06 ± 0.03
716483
8557071
07/09/2011 15:37
GM 3
1304
1387
1.31 ± 0.04
716665
8557038
07/09/2011 15:42
GM 3
685
728
0.69 ± 0.03
716675
8557059
07/09/2011 15:43
GM 3
401
426
0.40 ± 0.02
716687
8557082
07/09/2011 15:45
GM 3
341
363
0.34 ± 0.02
716702
8557108
07/09/2011 15:47
GM 3
290
308
0.29 ± 0.02
716569
8557151
08/09/2011 07:48
GM 3
2573
2736
2.58 ± 0.05
716574
8557169
08/09/2011 07:53
GM 3
2374
2524
2.38 ± 0.05
716576
8557190
08/09/2011 07:56
GM 3
2799
2976
2.81 ± 0.05
716572
8557211
08/09/2011 07:58
GM 3
2193
2332
2.20 ± 0.05
716561
8557229
08/09/2011 08:00
GM 3
1082
1151
1.09 ± 0.03
716547
8557246
08/09/2011 08:02
GM 3
610
649
0.61 ± 0.02
716536
8557266
08/09/2011 08:04
GM 3
830
883
0.83 ± 0.03
716531
8557278
08/09/2011 08:06
GM 3
545
580
0.55 ± 0.02
716526
8557298
08/09/2011 08:08
GM 3
623
662
0.62 ± 0.02
716512
8557319
08/09/2011 08:10
GM 3
575
611
0.58 ± 0.02
716501
8557340
08/09/2011 08:12
GM 3
403
429
0.40 ± 0.02
716496
8557362
08/09/2011 08:14
GM 3
630
670
0.63 ± 0.02
716487
8557382
08/09/2011 08:15
GM 3
989
1052
0.99 ± 0.03
716479
8557402
08/09/2011 08:17
GM 3
511
543
0.51 ± 0.02
716402
8557410
08/09/2011 08:26
GM 3
576
613
0.58 ± 0.02
716420
8557391
08/09/2011 08:29
GM 3
493
524
0.49 ± 0.02
716432
8557374
08/09/2011 08:31
GM 3
1187
1262
1.19 ± 0.03
716444
8557351
08/09/2011 08:32
GM 3
1081
1150
1.08 ± 0.03
716450
8557331
08/09/2011 08:35
GM 3
541
575
0.54 ± 0.02
716462
8557307
08/09/2011 08:37
GM 3
1047
1113
1.05 ± 0.03
716473
8557286
08/09/2011 08:39
GM 3
466
496
0.47 ± 0.02
716480
8557268
08/09/2011 08:47
GM 3
545
580
0.55 ± 0.02
716485
8557254
08/09/2011 08:50
GM 3
438
466
0.44 ± 0.02
716499
8557234
08/09/2011 08:51
GM 3
363
386
0.36 ± 0.02
716506
8557211
08/09/2011 08:53
GM 3
389
414
0.39 ± 0.02
716518
8557189
08/09/2011 08:55
GM 3
699
743
0.70 ± 0.03
716531
8557171
08/09/2011 08:57
GM 3
2509
2668
2.52 ± 0.05
716526
8557152
08/09/2011 08:59
GM 3
3559
3785
3.57 ± 0.06
716520
8557135
08/09/2011 09:01
GM 3
4059
4316
4.07 ± 0.06
716512
8557115
08/09/2011 09:03
GM 3
4307
4580
4.32 ± 0.06
716487
8557076
08/09/2011 09:26
GM 3
1260
1340
1.26 ± 0.03
716481
8557095
08/09/2011 09:29
GM 3
1052
1119
1.06 ± 0.03
81
716471
8557116
08/09/2011 09:31
GM 3
1522
1618
1.53 ± 0.04
716468
8557140
08/09/2011 09:34
GM 3
984
1046
0.99 ± 0.03
716464
8557158
08/09/2011 09:36
GM 3
1061
1128
1.06 ± 0.03
716459
8557182
08/09/2011 09:38
GM 3
331
352
0.33 ± 0.02
716454
8557202
08/09/2011 09:42
GM 3
343
365
0.34 ± 0.02
716447
8557220
08/09/2011 09:44
GM 3
381
405
0.38 ± 0.02
716436
8557234
08/09/2011 09:49
GM 3
442
470
0.44 ± 0.02
716426
8557252
08/09/2011 09:51
GM 3
386
410
0.39 ± 0.02
716414
8557271
08/09/2011 09:53
GM 3
347
369
0.35 ± 0.02
716402
8557292
08/09/2011 09:55
GM 3
405
431
0.41 ± 0.02
716389
8557310
08/09/2011 09:57
GM 3
788
838
0.79 ± 0.03
716380
8557322
08/09/2011 09:59
GM 3
895
952
0.90 ± 0.03
716371
8557334
08/09/2011 10:02
GM 3
1170
1244
1.17 ± 0.03
716361
8557348
08/09/2011 10:04
GM 3
1269
1349
1.27 ± 0.03
716354
8557359
08/09/2011 10:06
GM 3
637
677
0.64 ± 0.02
716349
8557374
08/09/2011 10:07
GM 3
997
1060
1.00 ± 0.03
716291
8557356
08/09/2011 10:11
GM 3
479
509
0.48 ± 0.02
716299
8557337
08/09/2011 10:16
GM 3
651
692
0.65 ± 0.02
716309
8557321
08/09/2011 10:18
GM 3
694
738
0.70 ± 0.03
716320
8557304
08/09/2011 10:20
GM 3
1392
1480
1.40 ± 0.04
716329
8557292
08/09/2011 10:23
GM 3
1669
1775
1.67 ± 0.04
716339
8557280
08/09/2011 10:24
GM 3
997
1060
1.00 ± 0.03
716353
8557266
08/09/2011 10:26
GM 3
294
313
0.29 ± 0.02
716364
8557249
08/09/2011 10:28
GM 3
416
442
0.42 ± 0.02
716372
8557235
08/09/2011 10:31
GM 3
895
952
0.90 ± 0.03
716381
8557221
08/09/2011 10:33
GM 3
653
694
0.66 ± 0.02
716393
8557202
08/09/2011 10:34
GM 3
453
482
0.45 ± 0.02
716401
8557184
08/09/2011 10:36
GM 3
381
405
0.38 ± 0.02
716410
8557164
08/09/2011 10:38
GM 3
477
507
0.48 ± 0.02
716421
8557146
08/09/2011 10:40
GM 3
922
980
0.92 ± 0.03
716429
8557127
08/09/2011 10:42
GM 3
3569
3795
3.58 ± 0.06
716432
8557115
08/09/2011 10:45
GM 3
2372
2522
2.38 ± 0.05
716437
8557101
08/09/2011 10:47
GM 3
1516
1612
1.52 ± 0.04
716442
8557085
08/09/2011 10:49
GM 3
1461
1554
1.47 ± 0.04
716450
8557069
08/09/2011 10:52
GM 3
1457
1549
1.46 ± 0.04
716453
8557053
08/09/2011 10:53
GM 3
1482
1576
1.49 ± 0.04
716458
8557036
08/09/2011 10:55
GM 3
1308
1391
1.31 ± 0.04
716465
8557025
08/09/2011 10:57
GM 3
1337
1422
1.34 ± 0.04
716433
8556947
08/09/2011 11:37
GM 3
786
836
0.79 ± 0.03
716427
8556970
08/09/2011 11:40
GM 3
677
720
0.68 ± 0.03
716419
8556991
08/09/2011 11:42
GM 3
916
974
0.92 ± 0.03
716416
8557005
08/09/2011 11:45
GM 3
912
970
0.91 ± 0.03
82
716409
8557026
08/09/2011 11:46
GM 3
757
805
0.76 ± 0.03
716401
8557044
08/09/2011 11:48
GM 3
1013
1077
1.02 ± 0.03
716391
8557062
08/09/2011 11:51
GM 3
805
856
0.81 ± 0.03
716389
8557078
08/09/2011 11:53
GM 3
1637
1741
1.64 ± 0.04
716377
8557096
08/09/2011 11:55
GM 3
432
459
0.43 ± 0.02
716363
8557116
08/09/2011 11:58
GM 3
814
866
0.82 ± 0.03
716356
8557138
08/09/2011 12:00
GM 3
1115
1186
1.12 ± 0.03
716349
8557156
08/09/2011 12:01
GM 3
546
581
0.55 ± 0.02
716338
8557175
08/09/2011 12:03
GM 3
880
936
0.88 ± 0.03
716325
8557195
08/09/2011 12:05
GM 3
391
416
0.39 ± 0.02
716315
8557210
08/09/2011 12:07
GM 3
821
873
0.82 ± 0.03
716304
8557231
08/09/2011 12:09
GM 3
538
572
0.54 ± 0.02
716291
8557247
08/09/2011 12:10
GM 3
553
588
0.55 ± 0.02
716286
8557262
08/09/2011 12:13
GM 3
850
904
0.85 ± 0.03
716274
8557279
08/09/2011 12:15
GM 3
565
601
0.57 ± 0.02
716265
8557295
08/09/2011 12:20
GM 3
740
787
0.74 ± 0.03
716258
8557309
08/09/2011 12:22
GM 3
662
704
0.66 ± 0.03
716248
8557326
08/09/2011 12:23
GM 3
929
988
0.93 ± 0.03
716245
8557335
08/09/2011 12:25
GM 3
674
717
0.68 ± 0.03
716188
8557316
08/09/2011 12:30
GM 3
704
749
0.71 ± 0.03
716201
8557299
08/09/2011 12:35
GM 3
2342
2490
2.35 ± 0.05
716209
8557287
08/09/2011 12:37
GM 3
1292
1374
1.30 ± 0.03
716216
8557271
08/09/2011 12:39
GM 3
1275
1356
1.28 ± 0.03
716225
8557251
08/09/2011 12:41
GM 3
754
802
0.76 ± 0.03
716238
8557226
08/09/2011 12:42
GM 3
883
939
0.89 ± 0.03
716246
8557212
08/09/2011 12:45
GM 3
646
687
0.65 ± 0.02
716261
8557192
08/09/2011 12:46
GM 3
260
276
0.26 ± 0.02
716273
8557174
08/09/2011 12:49
GM 3
256
272
0.26 ± 0.02
716288
8557149
08/09/2011 12:52
GM 3
247
263
0.25 ± 0.02
716299
8557132
08/09/2011 12:55
GM 3
368
391
0.37 ± 0.02
716309
8557118
08/09/2011 12:57
GM 3
457
486
0.46 ± 0.02
716324
8557098
08/09/2011 12:59
GM 3
658
700
0.66 ± 0.02
716330
8557085
08/09/2011 13:01
GM 3
1038
1104
1.04 ± 0.03
716343
8557065
08/09/2011 13:03
GM 3
836
889
0.84 ± 0.03
716352
8557050
08/09/2011 13:05
GM 3
707
752
0.71 ± 0.03
716358
8557033
08/09/2011 13:08
GM 3
765
813
0.77 ± 0.03
716363
8557009
08/09/2011 13:11
GM 3
1181
1256
1.18 ± 0.03
716368
8556992
08/09/2011 13:13
GM 3
851
905
0.85 ± 0.03
716368
8556966
08/09/2011 13:15
GM 3
286
304
0.29 ± 0.02
716369
8556943
08/09/2011 13:16
GM 3
895
952
0.90 ± 0.03
716377
8556924
08/09/2011 13:18
GM 3
325
346
0.33 ± 0.02
716389
8556905
08/09/2011 13:21
GM 3
433
460
0.43 ± 0.02
83
716337
8556930
08/09/2011 15:00
GM 3
928
987
0.93 ± 0.03
716332
8556957
08/09/2011 15:03
GM 3
688
732
0.69 ± 0.03
716329
8556979
08/09/2011 15:05
GM 3
293
312
0.29 ± 0.02
716319
8557000
08/09/2011 15:06
GM 3
715
760
0.72 ± 0.03
716310
8557019
08/09/2011 15:08
GM 3
848
902
0.85 ± 0.03
716302
8557034
08/09/2011 15:10
GM 3
800
851
0.80 ± 0.03
716293
8557049
08/09/2011 15:12
GM 3
792
842
0.79 ± 0.03
716282
8557066
08/09/2011 15:14
GM 3
751
799
0.75 ± 0.03
716271
8557083
08/09/2011 15:15
GM 3
966
1027
0.97 ± 0.03
716253
8557099
08/09/2011 15:18
GM 3
961
1022
0.96 ± 0.03
716238
8557116
08/09/2011 15:19
GM 3
1287
1369
1.29 ± 0.03
716224
8557133
08/09/2011 15:21
GM 3
1348
1433
1.35 ± 0.04
716212
8557151
08/09/2011 15:22
GM 3
782
832
0.78 ± 0.03
716203
8557171
08/09/2011 15:24
GM 3
1028
1093
1.03 ± 0.03
716196
8557193
08/09/2011 15:26
GM 3
993
1056
1.00 ± 0.03
716192
8557215
08/09/2011 15:29
GM 3
1498
1593
1.50 ± 0.04
716182
8557233
08/09/2011 15:31
GM 3
1185
1260
1.19 ± 0.03
716172
8557243
08/09/2011 15:33
GM 3
1119
1190
1.12 ± 0.03
716164
8557259
08/09/2011 15:35
GM 3
1147
1220
1.15 ± 0.03
716153
8557275
08/09/2011 15:36
GM 3
1124
1195
1.13 ± 0.03
716142
8557292
08/09/2011 15:38
GM 3
860
915
0.86 ± 0.03
716119
8557241
08/09/2011 15:41
GM 3
656
698
0.66 ± 0.02
716135
8557224
08/09/2011 15:43
GM 3
973
1035
0.98 ± 0.03
716142
8557203
08/09/2011 15:45
GM 3
1279
1360
1.28 ± 0.03
716148
8557185
08/09/2011 15:46
GM 3
1374
1461
1.38 ± 0.04
716156
8557165
08/09/2011 15:48
GM 3
2076
2208
2.08 ± 0.04
716165
8557147
08/09/2011 15:50
GM 3
1681
1788
1.69 ± 0.04
716171
8557129
08/09/2011 15:52
GM 3
1415
1505
1.42 ± 0.04
716179
8557108
08/09/2011 15:53
GM 3
1043
1109
1.05 ± 0.03
716185
8557105
08/09/2011 15:55
GM 3
1119
1190
1.12 ± 0.03
716198
8557088
08/09/2011 15:56
GM 3
1155
1228
1.16 ± 0.03
716211
8557072
08/09/2011 15:58
GM 3
855
909
0.86 ± 0.03
716224
8557056
08/09/2011 16:00
GM 3
1028
1093
1.03 ± 0.03
716240
8557038
08/09/2011 16:01
GM 3
872
927
0.87 ± 0.03
716254
8557020
08/09/2011 16:03
GM 3
860
915
0.86 ± 0.03
716264
8557002
08/09/2011 16:04
GM 3
555
590
0.56 ± 0.02
716275
8556983
08/09/2011 16:06
GM 3
270
287
0.27 ± 0.02
716285
8556966
08/09/2011 16:08
GM 3
233
248
0.23 ± 0.01
716197
8556955
08/09/2011 16:17
GM 3
885
941
0.89 ± 0.03
716175
8556971
08/09/2011 16:19
GM 3
564
600
0.57 ± 0.02
716158
8556986
08/09/2011 16:20
GM 3
705
750
0.71 ± 0.03
716142
8557010
08/09/2011 16:22
GM 3
625
665
0.63 ± 0.02
84
716132
8557027
08/09/2011 16:24
GM 3
439
467
0.44 ± 0.02
716553
8558038
09/09/2011 08:20
GM 3
199
212
0.20 ± 0.01
716535
8558022
09/09/2011 08:21
GM 3
188
200
0.19 ± 0.01
716533
8558002
09/09/2011 08:22
GM 3
158
168
0.16 ± 0.01
716695
8557601
09/09/2011 08:28
GM 3
452
481
0.45 ± 0.02
716670
8557592
09/09/2011 08:30
GM 3
420
447
0.42 ± 0.02
716638
8557576
09/09/2011 08:32
GM 3
517
550
0.52 ± 0.02
716612
8557571
09/09/2011 08:33
GM 3
387
412
0.39 ± 0.02
716213
8557668
07/09/2011 10:59
GM B
177
175
0.17 ± 0.01
716237
8557687
07/09/2011 11:01
GM B
218
216
0.20 ± 0.01
716261
8557702
07/09/2011 11:06
GM B
324
321
0.30 ± 0.02
716279
8557723
07/09/2011 11:08
GM B
1056
1045
0.99 ± 0.03
716299
8557734
07/09/2011 11:12
GM B
273
270
0.25 ± 0.02
716324
8557751
07/09/2011 11:13
GM B
181
179
0.17 ± 0.01
716351
8557767
07/09/2011 11:15
GM B
273
270
0.25 ± 0.02
716375
8557788
07/09/2011 11:17
GM B
273
270
0.25 ± 0.02
716403
8557804
07/09/2011 11:19
GM B
199
197
0.19 ± 0.01
716483
8557751
07/09/2011 11:25
GM B
295
292
0.28 ± 0.02
716468
8557740
07/09/2011 11:26
GM B
245
242
0.23 ± 0.01
716445
8557723
07/09/2011 11:28
GM B
317
314
0.30 ± 0.02
716424
8557705
07/09/2011 11:31
GM B
258
255
0.24 ± 0.02
716403
8557686
07/09/2011 11:33
GM B
201
199
0.19 ± 0.01
716380
8557668
07/09/2011 11:35
GM B
242
239
0.23 ± 0.01
716356
8557653
07/09/2011 11:36
GM B
523
517
0.49 ± 0.02
716334
8557638
07/09/2011 11:39
GM B
305
302
0.28 ± 0.02
716311
8557619
07/09/2011 11:40
GM B
324
321
0.30 ± 0.02
716287
8557606
07/09/2011 11:42
GM B
235
232
0.22 ± 0.01
716266
8557594
07/09/2011 11:43
GM B
385
381
0.36 ± 0.02
716244
8557585
07/09/2011 11:46
GM B
259
256
0.24 ± 0.02
716279
8557507
07/09/2011 11:52
GM B
270
267
0.25 ± 0.02
716296
8557517
07/09/2011 11:54
GM B
274
271
0.26 ± 0.02
716319
8557532
07/09/2011 11:55
GM B
244
241
0.23 ± 0.01
716346
8557547
07/09/2011 11:57
GM B
267
264
0.25 ± 0.02
716376
8557569
07/09/2011 11:59
GM B
261
258
0.24 ± 0.02
716395
8557583
07/09/2011 12:01
GM B
423
418
0.39 ± 0.02
716419
8557601
07/09/2011 12:02
GM B
253
250
0.24 ± 0.01
716439
8557619
07/09/2011 12:04
GM B
283
280
0.26 ± 0.02
716459
8557639
07/09/2011 12:05
GM B
263
260
0.25 ± 0.02
716481
8557659
07/09/2011 12:07
GM B
300
297
0.28 ± 0.02
716502
8557676
07/09/2011 12:08
GM B
327
323
0.31 ± 0.02
716522
8557694
07/09/2011 12:10
GM B
457
452
0.43 ± 0.02
716543
8557710
07/09/2011 12:12
GM B
276
273
0.26 ± 0.02
85
716562
8557728
07/09/2011 12:14
GM B
347
343
0.32 ± 0.02
716632
8557675
07/09/2011 12:26
GM B
277
274
0.26 ± 0.02
716614
8557657
07/09/2011 12:28
GM B
241
238
0.22 ± 0.01
716591
8557645
07/09/2011 12:30
GM B
296
293
0.28 ± 0.02
716567
8557628
07/09/2011 12:32
GM B
275
272
0.26 ± 0.02
716544
8557610
07/09/2011 12:33
GM B
305
302
0.28 ± 0.02
716521
8557596
07/09/2011 12:35
GM B
353
349
0.33 ± 0.02
716497
8557579
07/09/2011 12:37
GM B
314
311
0.29 ± 0.02
716473
8557565
07/09/2011 12:38
GM B
502
497
0.47 ± 0.02
716448
8557550
07/09/2011 12:40
GM B
270
267
0.25 ± 0.02
716426
8557533
07/09/2011 12:42
GM B
333
329
0.31 ± 0.02
716404
8557517
07/09/2011 12:44
GM B
276
273
0.26 ± 0.02
716379
8557499
07/09/2011 12:46
GM B
317
314
0.30 ± 0.02
716357
8557483
07/09/2011 12:47
GM B
258
255
0.24 ± 0.02
716334
8557469
07/09/2011 12:49
GM B
260
257
0.24 ± 0.02
716313
8557447
07/09/2011 12:50
GM B
272
269
0.25 ± 0.02
716286
8557430
07/09/2011 12:53
GM B
328
324
0.31 ± 0.02
716259
8557420
07/09/2011 12:54
GM B
622
615
0.58 ± 0.02
716231
8557414
07/09/2011 12:57
GM B
580
574
0.54 ± 0.02
716213
8557411
07/09/2011 13:00
GM B
548
542
0.51 ± 0.02
716253
8557349
07/09/2011 13:05
GM B
347
343
0.32 ± 0.02
716279
8557363
07/09/2011 13:06
GM B
363
359
0.34 ± 0.02
716305
8557375
07/09/2011 13:08
GM B
405
401
0.38 ± 0.02
716331
8557388
07/09/2011 13:09
GM B
433
428
0.40 ± 0.02
716359
8557404
07/09/2011 13:11
GM B
483
478
0.45 ± 0.02
716382
8557417
07/09/2011 13:14
GM B
359
355
0.34 ± 0.02
716410
8557430
07/09/2011 13:15
GM B
337
333
0.31 ± 0.02
716437
8557445
07/09/2011 13:17
GM B
243
240
0.23 ± 0.01
716465
8557459
07/09/2011 13:18
GM B
260
257
0.24 ± 0.02
716496
8557474
07/09/2011 13:21
GM B
261
258
0.24 ± 0.02
716520
8557484
07/09/2011 13:22
GM B
281
278
0.26 ± 0.02
716553
8557502
07/09/2011 13:24
GM B
571
565
0.53 ± 0.02
716505
8557430
07/09/2011 15:02
GM B
273
270
0.25 ± 0.02
716501
8557394
07/09/2011 15:04
GM B
282
279
0.26 ± 0.02
716513
8557360
07/09/2011 15:05
GM B
292
289
0.27 ± 0.02
716528
8557329
07/09/2011 15:07
GM B
283
280
0.26 ± 0.02
716546
8557301
07/09/2011 15:09
GM B
345
341
0.32 ± 0.02
716561
8557272
07/09/2011 15:11
GM B
357
353
0.33 ± 0.02
716582
8557242
07/09/2011 15:12
GM B
408
404
0.38 ± 0.02
716599
8557212
07/09/2011 15:15
GM B
515
509
0.48 ± 0.02
716607
8557189
07/09/2011 15:19
GM B
934
924
0.87 ± 0.03
716614
8557189
07/09/2011 15:21
GM B
482
477
0.45 ± 0.02
86
716627
8557179
07/09/2011 15:23
GM B
423
418
0.39 ± 0.02
716643
8557178
07/09/2011 15:24
GM B
332
328
0.31 ± 0.02
716627
8557190
07/09/2011 15:26
GM B
492
487
0.46 ± 0.02
716616
8557202
07/09/2011 15:27
GM B
400
396
0.37 ± 0.02
716658
8557193
07/09/2011 15:37
GM B
264
261
0.25 ± 0.02
716678
8557203
07/09/2011 15:39
GM B
477
472
0.45 ± 0.02
716699
8557210
07/09/2011 15:43
GM B
549
543
0.51 ± 0.02
716721
8557211
07/09/2011 15:44
GM B
466
461
0.43 ± 0.02
716741
8557203
07/09/2011 15:46
GM B
334
330
0.31 ± 0.02
716767
8557200
07/09/2011 15:48
GM B
297
294
0.28 ± 0.02
716765
8557183
07/09/2011 15:50
GM B
974
963
0.91 ± 0.03
716743
8557187
07/09/2011 15:51
GM B
333
329
0.31 ± 0.02
716722
8557189
07/09/2011 15:52
GM B
353
349
0.33 ± 0.02
716699
8557186
07/09/2011 15:54
GM B
440
435
0.41 ± 0.02
716674
8557186
07/09/2011 15:56
GM B
343
339
0.32 ± 0.02
716665
8557176
07/09/2011 15:57
GM B
305
302
0.28 ± 0.02
716687
8557170
07/09/2011 16:00
GM B
349
345
0.33 ± 0.02
716708
8557166
07/09/2011 16:01
GM B
381
377
0.36 ± 0.02
716728
8557162
07/09/2011 16:03
GM B
352
348
0.33 ± 0.02
716749
8557153
07/09/2011 16:04
GM B
334
330
0.31 ± 0.02
716701
8557132
07/09/2011 16:06
GM B
938
928
0.88 ± 0.03
716535
8557123
08/09/2011 07:50
GM B
5640
5579
5.26 ± 0.07
716539
8557140
08/09/2011 07:54
GM B
3564
3526
3.33 ± 0.06
716543
8557161
08/09/2011 07:56
GM B
3286
3251
3.07 ± 0.05
716546
8557174
08/09/2011 07:59
GM B
3268
3233
3.05 ± 0.05
716542
8557193
08/09/2011 08:01
GM B
1705
1687
1.59 ± 0.04
716531
8557208
08/09/2011 08:03
GM B
954
944
0.89 ± 0.03
716521
8557223
08/09/2011 08:04
GM B
559
553
0.52 ± 0.02
716511
8557245
08/09/2011 08:06
GM B
979
968
0.91 ± 0.03
716498
8557261
08/09/2011 08:09
GM B
573
567
0.53 ± 0.02
716490
8557282
08/09/2011 08:10
GM B
658
651
0.61 ± 0.02
716484
8557301
08/09/2011 08:12
GM B
614
607
0.57 ± 0.02
716477
8557321
08/09/2011 08:14
GM B
427
422
0.40 ± 0.02
716471
8557340
08/09/2011 08:16
GM B
557
551
0.52 ± 0.02
716461
8557357
08/09/2011 08:18
GM B
1313
1299
1.23 ± 0.03
716451
8557369
08/09/2011 08:20
GM B
1286
1272
1.20 ± 0.03
716441
8557383
08/09/2011 08:22
GM B
868
859
0.81 ± 0.03
716431
8557393
08/09/2011 08:23
GM B
782
774
0.73 ± 0.03
716420
8557406
08/09/2011 08:25
GM B
633
626
0.59 ± 0.02
716363
8557388
08/09/2011 08:27
GM B
542
536
0.51 ± 0.02
716373
8557372
08/09/2011 08:29
GM B
640
633
0.60 ± 0.02
716380
8557354
08/09/2011 08:31
GM B
1069
1057
1.00 ± 0.03
87
716392
8557343
08/09/2011 08:33
GM B
734
726
0.68 ± 0.03
716404
8557333
08/09/2011 08:35
GM B
1217
1204
1.14 ± 0.03
716415
8557317
08/09/2011 08:37
GM B
1654
1636
1.54 ± 0.04
716429
8557300
08/09/2011 08:39
GM B
616
609
0.57 ± 0.02
716440
8557283
08/09/2011 08:47
GM B
340
336
0.32 ± 0.02
716448
8557268
08/09/2011 08:49
GM B
363
359
0.34 ± 0.02
716452
8557251
08/09/2011 08:51
GM B
347
343
0.32 ± 0.02
716459
8557236
08/09/2011 08:53
GM B
417
413
0.39 ± 0.02
716464
8557218
08/09/2011 08:54
GM B
366
362
0.34 ± 0.02
716471
8557199
08/09/2011 08:56
GM B
349
345
0.33 ± 0.02
716479
8557182
08/09/2011 08:58
GM B
299
296
0.28 ± 0.02
716485
8557164
08/09/2011 09:00
GM B
396
392
0.37 ± 0.02
716494
8557149
08/09/2011 09:02
GM B
1351
1336
1.26 ± 0.03
716488
8557130
08/09/2011 09:04
GM B
1445
1429
1.35 ± 0.04
716490
8557117
08/09/2011 09:07
GM B
1373
1358
1.28 ± 0.03
716492
8557102
08/09/2011 09:09
GM B
2002
1980
1.87 ± 0.04
716496
8557085
08/09/2011 09:10
GM B
1574
1557
1.47 ± 0.04
716508
8557076
08/09/2011 09:25
GM B
1388
1373
1.30 ± 0.03
716469
8557038
08/09/2011 09:27
GM B
1602
1585
1.49 ± 0.04
716462
8557058
08/09/2011 09:30
GM B
1865
1845
1.74 ± 0.04
716460
8557078
08/09/2011 09:32
GM B
2235
2211
2.09 ± 0.04
716454
8557097
08/09/2011 09:34
GM B
1492
1476
1.39 ± 0.04
716447
8557113
08/09/2011 09:36
GM B
1347
1332
1.26 ± 0.03
716445
8557130
08/09/2011 09:38
GM B
2538
2511
2.37 ± 0.05
716441
8557148
08/09/2011 09:40
GM B
478
473
0.45 ± 0.02
716431
8557165
08/09/2011 09:44
GM B
310
307
0.29 ± 0.02
716423
8557184
08/09/2011 09:46
GM B
319
316
0.30 ± 0.02
716414
8557201
08/09/2011 09:49
GM B
442
437
0.41 ± 0.02
716403
8557221
08/09/2011 09:51
GM B
479
474
0.45 ± 0.02
716395
8557234
08/09/2011 09:53
GM B
377
373
0.35 ± 0.02
716383
8557249
08/09/2011 09:54
GM B
453
448
0.42 ± 0.02
716373
8557269
08/09/2011 09:56
GM B
378
374
0.35 ± 0.02
716358
8557283
08/09/2011 09:58
GM B
1617
1600
1.51 ± 0.04
716346
8557293
08/09/2011 10:00
GM B
682
675
0.64 ± 0.02
716336
8557305
08/09/2011 10:02
GM B
1574
1557
1.47 ± 0.04
716327
8557312
08/09/2011 10:05
GM B
1186
1173
1.11 ± 0.03
716319
8557321
08/09/2011 10:07
GM B
704
696
0.66 ± 0.02
716316
8557336
08/09/2011 10:09
GM B
674
667
0.63 ± 0.02
716309
8557352
08/09/2011 10:10
GM B
826
817
0.77 ± 0.03
716261
8557334
08/09/2011 10:14
GM B
434
429
0.40 ± 0.02
716271
8557318
08/09/2011 10:16
GM B
604
597
0.56 ± 0.02
716275
8557302
08/09/2011 10:18
GM B
667
660
0.62 ± 0.02
88
716284
8557291
08/09/2011 10:21
GM B
756
748
0.71 ± 0.03
716290
8557276
08/09/2011 10:23
GM B
555
549
0.52 ± 0.02
716300
8557262
08/09/2011 10:25
GM B
586
580
0.55 ± 0.02
716311
8557249
08/09/2011 10:27
GM B
698
690
0.65 ± 0.02
716323
8557235
08/09/2011 10:29
GM B
269
266
0.25 ± 0.02
716330
8557223
08/09/2011 10:31
GM B
245
242
0.23 ± 0.01
716336
8557208
08/09/2011 10:34
GM B
517
511
0.48 ± 0.02
716349
8557192
08/09/2011 10:36
GM B
588
582
0.55 ± 0.02
716361
8557178
08/09/2011 10:37
GM B
1068
1056
1.00 ± 0.03
716369
8557163
08/09/2011 10:39
GM B
3005
2973
2.80 ± 0.05
716375
8557143
08/09/2011 10:41
GM B
907
897
0.85 ± 0.03
716385
8557122
08/09/2011 10:43
GM B
458
453
0.43 ± 0.02
716395
8557103
08/09/2011 10:45
GM B
830
821
0.77 ± 0.03
716401
8557089
08/09/2011 10:47
GM B
1490
1474
1.39 ± 0.04
716409
8557076
08/09/2011 10:50
GM B
1966
1945
1.83 ± 0.04
716411
8557065
08/09/2011 10:53
GM B
1602
1585
1.49 ± 0.04
716418
8557049
08/09/2011 10:54
GM B
1016
1005
0.95 ± 0.03
716426
8557036
08/09/2011 10:56
GM B
1017
1006
0.95 ± 0.03
716429
8557021
08/09/2011 10:58
GM B
1487
1471
1.39 ± 0.04
716431
8557006
08/09/2011 10:59
GM B
1722
1703
1.61 ± 0.04
716431
8556991
08/09/2011 11:01
GM B
1295
1281
1.21 ± 0.03
716440
8556968
08/09/2011 11:03
GM B
1000
989
0.93 ± 0.03
716399
8556924
08/09/2011 11:38
GM B
451
446
0.42 ± 0.02
716391
8556942
08/09/2011 11:40
GM B
946
936
0.88 ± 0.03
716386
8556962
08/09/2011 11:42
GM B
352
348
0.33 ± 0.02
716381
8556981
08/09/2011 11:44
GM B
568
562
0.53 ± 0.02
716380
8556996
08/09/2011 11:46
GM B
831
822
0.78 ± 0.03
716379
8557010
08/09/2011 11:48
GM B
1552
1535
1.45 ± 0.04
716375
8557028
08/09/2011 11:51
GM B
786
778
0.73 ± 0.03
716366
8557043
08/09/2011 11:52
GM B
807
798
0.75 ± 0.03
716362
8557058
08/09/2011 11:54
GM B
798
789
0.74 ± 0.03
716351
8557073
08/09/2011 11:56
GM B
640
633
0.60 ± 0.02
716341
8557093
08/09/2011 11:58
GM B
607
600
0.57 ± 0.02
716331
8557112
08/09/2011 12:00
GM B
3073
3040
2.87 ± 0.05
716321
8557128
08/09/2011 12:02
GM B
627
620
0.59 ± 0.02
716310
8557144
08/09/2011 12:03
GM B
320
317
0.30 ± 0.02
716299
8557160
08/09/2011 12:05
GM B
256
253
0.24 ± 0.02
716292
8557175
08/09/2011 12:07
GM B
244
241
0.23 ± 0.01
716284
8557190
08/09/2011 12:09
GM B
258
255
0.24 ± 0.02
716271
8557203
08/09/2011 12:11
GM B
275
272
0.26 ± 0.02
716263
8557216
08/09/2011 12:13
GM B
430
425
0.40 ± 0.02
716255
8557233
08/09/2011 12:15
GM B
1332
1318
1.24 ± 0.03
89
716251
8557247
08/09/2011 12:17
GM B
774
766
0.72 ± 0.03
716240
8557258
08/09/2011 12:19
GM B
829
820
0.77 ± 0.03
716229
8557274
08/09/2011 12:21
GM B
945
935
0.88 ± 0.03
716224
8557287
08/09/2011 12:23
GM B
1024
1013
0.96 ± 0.03
716215
8557302
08/09/2011 12:24
GM B
1090
1078
1.02 ± 0.03
716207
8557317
08/09/2011 12:26
GM B
578
572
0.54 ± 0.02
716159
8557290
08/09/2011 12:33
GM B
766
758
0.71 ± 0.03
716168
8557275
08/09/2011 12:35
GM B
1526
1510
1.42 ± 0.04
716177
8557264
08/09/2011 12:37
GM B
1542
1525
1.44 ± 0.04
716186
8557249
08/09/2011 12:39
GM B
1247
1234
1.16 ± 0.03
716198
8557229
08/09/2011 12:41
GM B
1286
1272
1.20 ± 0.03
716208
8557209
08/09/2011 12:43
GM B
674
667
0.63 ± 0.02
716214
8557189
08/09/2011 12:45
GM B
1324
1310
1.24 ± 0.03
716220
8557177
08/09/2011 12:47
GM B
1238
1225
1.16 ± 0.03
716228
8557159
08/09/2011 12:49
GM B
1636
1618
1.53 ± 0.04
716238
8557144
08/09/2011 12:51
GM B
1094
1082
1.02 ± 0.03
716248
8557125
08/09/2011 12:52
GM B
750
742
0.70 ± 0.03
716263
8557116
08/09/2011 12:55
GM B
752
744
0.70 ± 0.03
716279
8557101
08/09/2011 12:57
GM B
845
836
0.79 ± 0.03
716285
8557085
08/09/2011 12:58
GM B
643
636
0.60 ± 0.02
716294
8557071
08/09/2011 13:00
GM B
650
643
0.61 ± 0.02
716306
8557054
08/09/2011 13:02
GM B
903
893
0.84 ± 0.03
716316
8557039
08/09/2011 13:04
GM B
735
727
0.69 ± 0.03
716323
8557026
08/09/2011 13:06
GM B
781
773
0.73 ± 0.03
716329
8557014
08/09/2011 13:07
GM B
1042
1031
0.97 ± 0.03
716334
8556999
08/09/2011 13:11
GM B
1168
1155
1.09 ± 0.03
716340
8556976
08/09/2011 13:13
GM B
417
413
0.39 ± 0.02
716342
8556946
08/09/2011 13:15
GM B
605
598
0.56 ± 0.02
716346
8556933
08/09/2011 13:17
GM B
925
915
0.86 ± 0.03
716350
8556916
08/09/2011 13:19
GM B
625
618
0.58 ± 0.02
716351
8556899
08/09/2011 13:22
GM B
272
269
0.25 ± 0.02
716315
8556939
08/09/2011 15:02
GM B
680
673
0.63 ± 0.02
716310
8556953
08/09/2011 15:04
GM B
253
250
0.24 ± 0.01
716311
8556972
08/09/2011 15:06
GM B
352
348
0.33 ± 0.02
716303
8556992
08/09/2011 15:07
GM B
575
569
0.54 ± 0.02
716295
8557010
08/09/2011 15:09
GM B
841
832
0.78 ± 0.03
716284
8557023
08/09/2011 15:10
GM B
1188
1175
1.11 ± 0.03
716277
8557037
08/09/2011 15:12
GM B
917
907
0.86 ± 0.03
716264
8557052
08/09/2011 15:14
GM B
866
857
0.81 ± 0.03
716253
8557068
08/09/2011 15:16
GM B
1021
1010
0.95 ± 0.03
716241
8557081
08/09/2011 15:18
GM B
959
949
0.89 ± 0.03
716225
8557097
08/09/2011 15:20
GM B
994
983
0.93 ± 0.03
90
716213
8557114
08/09/2011 15:22
GM B
1035
1024
0.97 ± 0.03
716201
8557131
08/09/2011 15:23
GM B
1061
1050
0.99 ± 0.03
716188
8557148
08/09/2011 15:26
GM B
1235
1222
1.15 ± 0.03
716185
8557169
08/09/2011 15:27
GM B
1270
1256
1.19 ± 0.03
716177
8557190
08/09/2011 15:29
GM B
1265
1251
1.18 ± 0.03
716173
8557209
08/09/2011 15:32
GM B
1371
1356
1.28 ± 0.03
716166
8557223
08/09/2011 15:33
GM B
1029
1018
0.96 ± 0.03
716157
8557239
08/09/2011 15:36
GM B
1011
1000
0.94 ± 0.03
716146
8557253
08/09/2011 15:37
GM B
1176
1163
1.10 ± 0.03
716133
8557264
08/09/2011 15:38
GM B
609
602
0.57 ± 0.02
716098
8557228
08/09/2011 15:44
GM B
440
435
0.41 ± 0.02
716100
8557200
08/09/2011 15:46
GM B
456
451
0.43 ± 0.02
716112
8557170
08/09/2011 15:49
GM B
600
594
0.56 ± 0.02
716124
8557135
08/09/2011 15:52
GM B
960
950
0.90 ± 0.03
716128
8557117
08/09/2011 15:54
GM B
1028
1017
0.96 ± 0.03
716146
8557094
08/09/2011 15:55
GM B
968
958
0.90 ± 0.03
716156
8557076
08/09/2011 15:57
GM B
625
618
0.58 ± 0.02
716176
8557055
08/09/2011 15:59
GM B
334
330
0.31 ± 0.02
716190
8557031
08/09/2011 16:01
GM B
239
236
0.22 ± 0.01
716204
8557020
08/09/2011 16:02
GM B
280
277
0.26 ± 0.02
716216
8556999
08/09/2011 16:04
GM B
396
392
0.37 ± 0.02
716227
8556982
08/09/2011 16:06
GM B
493
488
0.46 ± 0.02
716244
8556960
08/09/2011 16:09
GM B
211
209
0.20 ± 0.01
716213
8556941
08/09/2011 16:14
GM B
238
235
0.22 ± 0.01
716184
8556929
08/09/2011 16:17
GM B
909
899
0.85 ± 0.03
716156
8556945
08/09/2011 16:19
GM B
481
476
0.45 ± 0.02
716138
8556959
08/09/2011 16:21
GM B
1214
1201
1.13 ± 0.03
716119
8556984
08/09/2011 16:22
GM B
1076
1064
1.00 ± 0.03
716105
8557014
08/09/2011 16:24
GM B
373
369
0.35 ± 0.02
716093
8557046
08/09/2011 16:26
GM B
459
454
0.43 ± 0.02
716110
8557068
08/09/2011 16:28
GM B
430
425
0.40 ± 0.02
716097
8557096
08/09/2011 16:30
GM B
792
783
0.74 ± 0.03
716078
8557111
08/09/2011 16:31
GM B
477
472
0.45 ± 0.02
91
Appendix E Soil radionuclide activity concentrations and
associated gamma dose rates at selected points
Table E1 Results of soil radionuclide activity concentration (Bq kg-1) and external gamma dose rate
measurements (µGy h-1) at selected points at RJCS.
Point
Sample
238
226
210
228
40
µGy h-1
1
RJS11020
1643 ± 164
1175 ± 10
1152 ± 23
25 ± 4
210 ± 19
0.46 ± 0.02
2
RJS11021
961 ± 96
480 ± 5
595 ± 14
28 ± 3
96 ± 12
0.3 ± 0.02
3
RJS11022
571 ± 57
389 ± 4
435 ± 12
47 ± 3
118 ± 12
0.36 ± 0.02
4
RJS11023
1016 ± 102
392 ± 4
450 ± 15
32 ± 3
49 ± 10
0.26 ± 0.02
5
RJS11024
415 ± 41
296 ± 3
288 ± 10
53 ± 3
113 ± 12
0.2 ± 0.01
7
RJS11025
874 ± 87
699 ± 5
711 ± 18
33 ± 3
199 ± 15
0.38 ± 0.02
8
RJS11026
315 ± 31
259 ± 3
279 ± 11
43 ± 3
89 ± 11
0.24 ± 0.02
9
RJS11027
398 ± 40
346 ± 4
458 ± 15
36 ± 3
98 ± 12
0.22 ± 0.01
10
RJS11028
340 ± 34
175 ± 3
202 ± 9
53 ± 3
79 ± 11
na
11
RJS11029
514 ± 51
529 ± 5
558 ± 16
43 ± 3
87 ± 12
0.39 ± 0.02
12
RJS11030
240 ± 24
153 ± 2
183 ± 7
46 ± 2
64 ± 7
0.22 ± 0.01
13
RJS11031
727 ± 73
354 ± 4
454 ± 15
36 ± 3
55 ± 12
0.29 ± 0.02
14
RJS11032
2013 ± 201
2225 ± 17
2584 ± 41
31 ± 5
362 ± 26
1.02 ± 0.03
15
RJS11033
2309 ± 231
1117 ± 9
1230 ± 24
35 ± 4
284 ± 19
0.95 ± 0.03
16
RJS11034
2519 ± 252
2191 ± 13
2554 ± 42
36 ± 5
439 ± 23
0.96 ± 0.03
17
RJS11035
2692 ± 269
1784 ± 14
1818 ± 32
39 ± 5
239 ± 22
0.85 ± 0.03
18
RJS11036
2371 ± 237
739 ± 5
888 ± 19
39 ± 3
181 ± 13
0.54 ± 0.02
19
RJS11037
2038 ± 204
1067 ± 7
983 ± 22
59 ± 4
276 ± 17
0.51 ± 0.02
20
RJS11038
484 ± 48
272 ± 3
352 ± 13
49 ± 3
89 ± 12
0.27 ± 0.02
21
RJS11039
2025 ± 203
5395 ± 39
5499 ± 76
50 ± 7
358 ± 31
4.46 ± 0.06
22
RJS11040
147 ± 15
130 ± 2
126 ± 8
59 ± 3
96 ± 10
0.28 ± 0.02
23
RJS11041
2976 ± 298
1463 ± 11
1701 ± 26
44 ± 3
254 ± 15
1.59 ± 0.04
24
RJS11042
3841 ± 384
2191 ± 13
2702 ± 45
33 ± 5
442 ± 23
1.61 ± 0.04
25
RJS11043
3372 ± 337
3732 ± 21
3941 ± 61
25 ± 6
381 ± 26
1.62 ± 0.04
26
RJS11044
1853 ± 185
1655 ± 13
1714 ± 30
27 ± 4
365 ± 23
0.76 ± 0.03
27
RJS11045
228 ± 23
192 ± 2
208 ± 9
59 ± 3
101 ± 10
0.56 ± 0.02
28
RJS11046
851 ± 85
321 ± 4
349 ± 12
53 ± 3
117 ± 13
0.48 ± 0.02
30
RJS11047
117 ± 12
100 ± 2
135 ± 7
55 ± 3
751 ± 22
0.19 ± 0.01
H
RJS11017
5014 ± 501
9739 ± 51
9973 ± 136
28 ± 8
554 ± 34
5.81 ± 0.07
U
Ra
Pb
92
Ra
K
Appendix F Radon exhalation flux density measurements
Table F1 Sampling locations and dates and radon exhalation flux densities (mBq m-2 s-1). Data for each
individual charcoal canister (cup) are shown, as well as the arithmetic mean (average) for each point.
Point
Cup #
Easting
Northing
Deployed
Collected
Flux
Average
1
93
716816
8557217
07/07/2011 12:37
11/07/2011 12:21
195 ± 2
217 ± 30
97
2
2
238 ± 3
716745
8557192
07/07/2011 12:30
11/07/2011 12:14
27
3
3
62
716613
8557211
07/07/2011 12:20
11/07/2011 12:26
10
716555
8557337
07/07/2011 12:45
11/07/2011 14:16
20
716537
8557690
07/07/2011 13:45
11/07/2011 13:49
75
716631
8557598
07/07/2011 13:49
11/07/2011 13:52
29
716524
8557530
07/07/2011 13:08
11/07/2011 14:12
16
716398
8557747
07/07/2011 13:40
11/07/2011 13:43
12
13
19
716295
8557630
07/07/2011 13:34
11/07/2011 13:39
716429
8557578
07/07/2011 13:15
11/07/2011 13:32
16
18
209 ± 3
474 ± 4
321 ± 3
716433
8557487
07/07/2011 13:20
11/07/2011 13:30
322 ± 3
78
254 ± 3
91
266 ± 3
716308
8557422
07/07/2011 13:24
11/07/2011 13:22
8
37
960 ± 5
716443
8557385
07/07/2011 09:37
11/07/2011 11:28
606 ± 4
716315
8557312
07/07/2011 09:47
11/07/2011 11:35
487 ± 4
614 ± 4
74
558 ± 4
7
716158
8557246
07/07/2011 09:56
11/07/2011 11:43
1053 ± 5
472 ± 371
608 ± 371
281 ± 36
539 ± 596
607 ± 2
553 ± 64
809 ± 345
565 ± 4
716205
8557130
07/07/2011 10:03
11/07/2011 11:48
120 ± 2
25
663 ± 4
90
1164 ± 5
24
132 ± 25
609 ± 4
61
31
265 ± 9
117 ± 2
60
17
114 ± 2
76
82
15
258 ± 3
1027 ± 6
66
237 ± 162
734 ± 5
77
14
122 ± 2
35
36
153 ± 58
150 ± 2
17
11
194 ± 3
271 ± 3
71
10
251 ± 74
351 ± 3
95
9
303 ± 3
112 ± 2
87
8
580 ± 18
199 ± 2
81
7
593 ± 4
567 ± 4
80
5
344 ± 171
223 ± 2
38
4
465 ± 4
716342
8557210
07/07/2011 11:12
93
11/07/2011 10:22
174 ± 2
649 ± 522
200 ± 74
19
70
283 ± 3
84
143 ± 2
79
716471
8557290
07/07/2011 12:53
11/07/2011 10:05
92
20
21
22
23
24
25
26
27
28
18
177 ± 2
323 ± 3
716577
8557284
07/07/2011 12:11
11/07/2011 11:20
234 ± 3
26
231 ± 3
96
176 ± 2
1
716537
8557121
07/07/2011 10:36
11/07/2011 10:48
1082 ± 5
94*
22 ± 1
99
868 ± 5
0
716468
8557191
07/07/2011 11:36
11/07/2011 13:08
447 ± 4
86
314 ± 3
9e
392 ± 4
9
716380
8557170
07/07/2011 11:29
11/07/2011 10:28
1076 ± 5
11
531 ± 4
22
583 ± 4
64
716445
8557090
07/07/2011 10:26
11/07/2011 10:44
1078 ± 5
72
1370 ± 6
88
683 ± 4
15
716407
8557019
07/07/2011 10:17
11/07/2011 12:05
2004 ± 7
32
2527 ± 8
69
605 ± 4
30
716280
8557053
07/07/2011 10:11
11/07/2011 11:55
521 ± 4
83
1027 ± 5
89
325 ± 3
12
716363
8557112
07/07/2011 10:59
11/07/2011 10:34
1621 ± 7
28
1454 ± 6
68
422 ± 3
14
250 ± 104
716402
8557286
07/07/2011 12:57
11/07/2011 10:11
98
186 ± 2
214 ± 333
975 ± 151
385 ± 67
730 ± 301
1043 ± 345
1712 ± 994
624 ± 362
1166 ± 649
181 ± 7
176 ± 2
30
63
716569
8558008
07/07/2011 14:10
11/07/2011 14:04
22 ± 1
22 ± 1
H
13
716546
8557153
07/07/2011 10:46
11/07/2011 10:54
4509 ± 11
4425 ± 549
40
3838 ± 10
100
4927 ± 12
94
Appendix G Results of diurnal radon activity concentration
measurements at RJCS, 7–9 September 2011
Table G1 Three-hourly data for airborne radon concentrations (Bq m-3) measured at RJCS. Data were
measured using a Durridge RAD7 radon detector.
Point
Sampling period
Radon concentration
3
7/09/2011 14:49 - 17:49
1.9 ± 5.2
3
7/09/2011 17:49 - 20:49
11.3 ± 5.9
3
7/09/2011 20:49 - 23:49
66.9 ± 12.1
3
8/09/2011 23:49 - 2:49
210 ± 21
3
8/09/2011 2:49 - 5:49
176 ± 19
3
8/09/2011 5:49 - 8:49
239 ± 22
3
8/09/2011 8:49 - 11:49
25.3 ± 8.1
3
8/09/2011 11:49 - 14:49
4.5 ± 5.2
3
8/09/2011 14:49 - 17:49
10.4 ± 5.8
3
8/09/2011 17:49 - 20:49
32.1 ± 8.9
3
8/09/2011 20:49 - 23:49
164 ± 18
3
9/09/2011 23:49 - 2:49
377 ± 27
3
9/09/2011 2:49 - 5:49
321 ± 25
3
9/09/2011 5:49 - 8:49
326 ± 25
3
9/09/2011 8:49 - 11:49
42.5 ± 10.1
95
Appendix H Results of diurnal radon decay product potential
alpha energy concentration measurements
Table H1 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at RJCS, 13–
14 January 2011. Data were measured using an environmental radon daughter monitor.
Point
Sampling period
PAEC
3
13/01/2011 10:30 - 11:30
0.002 ± 0.001
3
13/01/2011 11:30 - 12:30
0.004 ± 0.002
3
13/01/2011 12:30 - 13:30
0.001 ± 0.001
3
13/01/2011 13:30 - 14:30
0.001 ± 0.001
3
13/01/2011 14:30 - 15:30
0.003 ± 0.001
3
13/01/2011 15:30 - 16:30
0.002 ± 0.001
3
13/01/2011 16:30 - 17:30
0.002 ± 0.001
3
13/01/2011 17:30 - 18:30
0.001 ± 0.001
3
13/01/2011 18:30 - 19:30
0.001 ± 0.001
3
13/01/2011 19:30 - 20:30
0.001 ± 0.001
3
13/01/2011 20:30 - 21:30
0.002 ± 0.001
3
13/01/2011 21:30 - 22:30
0.005 ± 0.002
3
13/01/2011 22:30 - 23:30
0.009 ± 0.002
3
13/01/2011 23:30 - 0:30
0.007 ± 0.002
3
14/01/2011 0:30 - 1:30
0.006 ± 0.002
3
14/01/2011 1:30 - 2:30
0.014 ± 0.003
3
14/01/2011 2:30 - 3:30
0.023 ± 0.004
3
14/01/2011 3:30 - 4:30
0.051 ± 0.006
3
14/01/2011 4:30 - 5:30
0.074 ± 0.007
3
14/01/2011 5:30 - 6:30
0.034 ± 0.005
3
14/01/2011 6:30 - 7:30
0.017 ± 0.003
3
14/01/2011 7:30 - 8:30
0.008 ± 0.002
3
14/01/2011 8:30 - 9:30
0.003 ± 0.001
3
14/01/2011 9:30 – 10:30
0.003 ± 0.001
Table H2 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at RJCS, 7–9
September 2011. Data were measured using an environmental radon daughter monitor.
Point
Sampling period
PAEC
3
7/09/2011 14:50 - 15:50
0.003 ± 0.001
3
7/09/2011 15:50 - 16:50
0.013 ± 0.003
3
7/09/2011 16:50 - 17:50
0.019 ± 0.003
3
7/09/2011 17:50 - 18:50
0.013 ± 0.003
3
7/09/2011 18:50 - 19:50
0.012 ± 0.003
3
7/09/2011 19:50 - 20:50
0.017 ± 0.003
3
7/09/2011 20:50 - 215:50
0.032 ± 0.004
3
7/09/2011 21:50 - 22:50
0.03 ± 0.004
96
3
7/09/2011 22:50 - 23:50
0.053 ± 0.006
3
7/09/2011 23:50 - 24:50
0.217 ± 0.011
3
8/09/2011 0:50 - 1:50
0.523 ± 0.017
3
8/09/2011 1:50 - 2:50
0.578 ± 0.018
3
8/09/2011 2:50 - 3:50
0.265 ± 0.012
3
8/09/2011 3:50 - 4:50
0.384 ± 0.015
3
8/09/2011 4:50 - 5:50
0.571 ± 0.018
3
8/09/2011 5:50 - 6:50
0.662 ± 0.02
3
8/09/2011 6:50 - 7:50
0.792 ± 0.021
3
8/09/2011 7:50 - 8:50
0.522 ± 0.017
3
8/09/2011 8:50 - 9:50
0.172 ± 0.01
3
8/09/2011 9:50 - 10:50
0.086 ± 0.007
3
8/09/2011 10:50 - 11:50
0.049 ± 0.005
3
8/09/2011 11:50 - 12:50
0.046 ± 0.005
3
8/09/2011 12:50 - 13:50
0.037 ± 0.005
3
8/09/2011 13:50 - 14:50
0.031 ± 0.004
3
8/09/2011 14:50 - 15:50
0.023 ± 0.004
3
8/09/2011 15:50 - 16:50
0.031 ± 0.004
3
8/09/2011 16:50 - 17:50
0.025 ± 0.004
3
8/09/2011 17:50 - 18:50
0.028 ± 0.004
3
8/09/2011 18:50 - 19:50
0.03 ± 0.004
3
8/09/2011 19:50 - 20:50
0.028 ± 0.004
3
8/09/2011 20:50 - 21:50
0.071 ± 0.006
3
8/09/2011 21:50 - 22:50
0.12 ± 0.008
3
8/09/2011 22:50 - 23:50
0.284 ± 0.013
3
8/09/2011 23:50 - 0:50
0.653 ± 0.019
3
9/09/2011 0:50 - 1:50
0.564 ± 0.018
3
9/09/2011 1:50 - 2:50
0.73 ± 0.021
3
9/09/2011 2:50 - 3:50
0.741 ± 0.021
3
9/09/2011 3:50 - 4:50
0.802 ± 0.022
3
9/09/2011 4:50 - 5:50
0.817 ± 0.022
3
9/09/2011 5:50 - 6:50
0.766 ± 0.021
3
9/09/2011 6:50 - 7:50
0.632 ± 0.019
3
9/09/2011 7:50 - 8:50
0.454 ± 0.016
3
9/09/2011 8:50 - 9:50
0.195 ± 0.011
3
9/09/2011 9:50 - 10:50
0.09 ± 0.007
Table H3 Hourly data for potential alpha energy concentration (PAEC, µJ m-3) measured at BBFC, 7–9
September 2011. Data were measured using an environmental radon daughter monitor.
Site
Sampling period
PAEC
BBFC
7/09/2011 8:56 – 9:56
0.025 ± 0.003
BBFC
7/09/2011 9:56 – 10:56
0.047 ± 0.005
97
BBFC
7/09/2011 10:56 – 11:56
0.031 ± 0.004
BBFC
7/09/2011 11:56 – 12:56
0.03 ± 0.004
BBFC
7/09/2011 12:56 – 13:56
0.028 ± 0.004
BBFC
7/09/2011 13:56 – 14:56
0.025 ± 0.003
BBFC
7/09/2011 14:56 – 15:56
0.022 ± 0.003
BBFC
7/09/2011 15:56 – 16:56
0.017 ± 0.003
BBFC
7/09/2011 16:56 – 17:56
0.013 ± 0.003
BBFC
7/09/2011 17:56 – 18:56
0.013 ± 0.002
BBFC
7/09/2011 18:56 – 19:56
0.016 ± 0.003
BBFC
7/09/2011 19:56 – 20:56
0.02 ± 0.003
BBFC
7/09/2011 20:56 – 21:56
0.021 ± 0.003
BBFC
7/09/2011 21:56 – 22:56
0.028 ± 0.004
BBFC
7/09/2011 22:56 – 23:56
0.018 ± 0.003
BBFC
7/09/2011 23:56 – 0:56
0.039 ± 0.004
BBFC
8/09/2011 0:56 – 1:56
0.057 ± 0.005
BBFC
8/09/2011 1:56 – 2:56
0.097 ± 0.007
BBFC
8/09/2011 2:56 – 3:56
0.105 ± 0.007
BBFC
8/09/2011 3:56 – 4:56
0.097 ± 0.007
BBFC
8/09/2011 4:56 – 5:56
0.096 ± 0.007
BBFC
8/09/2011 5:56 – 6:56
0.146 ± 0.008
BBFC
8/09/2011 6:56 – 7:56
0.209 ± 0.01
BBFC
8/09/2011 7:56 – 8:56
0.221 ± 0.01
BBFC
8/09/2011 8:56 – 9:56
0.118 ± 0.008
BBFC
8/09/2011 9:56 – 10:56
0.06 ± 0.005
BBFC
8/09/2011 10:56 – 11:56
0.05 ± 0.005
BBFC
8/09/2011 11:56 – 12:56
0.036 ± 0.004
BBFC
8/09/2011 12:56 – 13:56
0.032 ± 0.004
BBFC
8/09/2011 13:56 – 14:56
0.042 ± 0.005
BBFC
8/09/2011 14:56 – 15:56
0.036 ± 0.004
BBFC
8/09/2011 15:56 – 16:56
0.028 ± 0.004
BBFC
8/09/2011 16:56 – 17:56
0.03 ± 0.004
BBFC
8/09/2011 17:56 – 18:56
0.031 ± 0.004
BBFC
8/09/2011 18:56 – 19:56
0.032 ± 0.004
BBFC
8/09/2011 19:56 – 20:56
0.025 ± 0.003
BBFC
8/09/2011 20:56 – 21:56
0.031 ± 0.004
BBFC
8/09/2011 21:56 – 22:56
0.036 ± 0.004
BBFC
8/09/2011 22:56 – 23:56
0.034 ± 0.004
BBFC
8/09/2011 23:56 – 0:56
0.046 ± 0.005
BBFC
9/09/2011 0:56 – 1:56
0.065 ± 0.006
BBFC
9/09/2011 1:56 – 2:56
0.077 ± 0.006
BBFC
9/09/2011 2:56 – 3:56
0.089 ± 0.007
BBFC
9/09/2011 3:56 – 4:56
0.142 ± 0.008
98
BBFC
9/09/2011 4:56 – 5:56
0.131 ± 0.008
BBFC
9/09/2011 5:56 – 6:56
0.137 ± 0.008
BBFC
9/09/2011 6:56 – 7:56
0.111 ± 0.007
BBFC
9/09/2011 7:56 – 8:56
0.08 ± 0.006
BBFC
9/09/2011 8:56 – 9:56
0.077 ± 0.006
BBFC
9/09/2011 9:56 – 10:56
0.055 ± 0.005
BBFC
9/09/2011 10:56 – 1156
0.048 ± 0.005
99
Appendix I Airborne radon activity concentrations
Table I1 Data for airborne radon concentrations (Bq m-3). Typical uncertainties for the measurement of
radon activity concentrations using track etch detectors are 30%. Track etch detectors were deployed
from 7 July to 9 September 2011. Data are shown for each individual track etch detector, as well as the
arithmetic mean (average) for each selected measurement point. Results for the background (BBFC)
and control (eriss) track etch detectors are also shown.
Point
Easting
Northing
TED #
Concentration
Average
1
716816
8557217
55
249 ± 75
233 ± 24
57
216 ± 65
58
102 ± 31
70
127 ± 38
21
194 ± 58
15
222 ± 66
42
238 ± 71
44
144 ± 43
75 cm
67
On ground
75 cm
61
On ground
20 cm
27
577 ± 173
20 cm
36
543 ± 163
13
266 ± 80
19
177 ± 53
23
44 ± 13
25
105 ± 32
2
105 ± 32
39
119 ± 36
10
66 ± 20
12
138 ± 41
3
94 ± 28
8
144 ± 43
49
Not found
43
Not found
14
122 ± 36
16
166 ± 50
22
127 ± 38
24
185 ± 56
5
160 ± 48
9
183 ± 55
31
36 ± 18
38
111 ± 33
32
On ground
34
On ground
26
On ground
2
3
4
5
7
8
9
10
11
12
13
14
15
16
716745
716613
716555
716537
716631
716524
716398
716295
716429
716433
716308
716443
716315
716158
8557192
8557211
8557337
8557690
8557598
8557530
8557747
8557630
8557578
8557487
8557422
8557385
8557312
8557246
100
115 ± 18
208 ± 20
191 ± 67
560 ± 24
221 ± 63
74 ± 43
112 ± 10
102 ± 51
119 ± 35
144 ± 31
156 ± 41
172 ± 16
73 ± 53
35
On ground
56
111 ± 33
66
202 ± 61
52
On ground
69
On ground
6
88 ± 26
11
77 ± 23
60
On ground
68
On ground
59
435
51
Failed
53
55 ± 17
63
55 ± 17
54
72 ± 22
65
38 ± 19
29
88 ± 26
30
83 ± 25
1
116 ± 35
7
122 ± 36
17
94 ± 28
20
50 ± 15
62
50 ± 15
64
38 ± 19
4
72 ± 22
18
66 ± 20
41
27 ± 14
45
33 ± 16
28
205 ± 61
33
216 ± 65
BBFC
50
50 ± 15
BBFC
48
16 ± 8
eriss
37
< 11
eriss
40
< 11
eriss
46
< 11
eriss
47
< 11
17
18
19
20
21
22
23
24
25
26
27
28
30
H
716205
716342
716471
716577
716537
716468
716380
716445
716407
716280
716363
716402
716569
716546
8557130
8557210
8557290
8557284
8557121
8557191
8557170
8557090
8557019
8557053
8557112
8557286
8558008
8557153
101
156 ± 65
83 ± 8
435 ± 131
55 ± 1
55 ± 24
86 ± 4
119 ± 4
72 ± 31
44 ± 8
69 ± 4
30 ± 4
210 ± 8
33 ± 24
Appendix J Photos of sampled fruit
Figure J1 Ficus racemosa (cluster fig)
Figure J2 Flueggea virosa (white currant)
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Figure J3 Passiflora foetida (passionfruit)
Figure J4 Physalis minima (gooseberry) plant and fruit
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