A classification system for pressures related to hazardous
water emissions from mine sites - comparison of pressures in
ten EU Accession Countries
ERIK PUURA
Institute of Technology
University of Tartu
Vanemuise 21
50110 Tartu, ESTONIA
MARCO D’ALESSANDRO
Institute for Environment and Sustainability
Joint Research Centre of the European Commission
I-21020 Ispra (VA), ITALY
Abstract
A survey of information on the hazardous water emissions from mine sites in the Central
and Eastern European EU Accession Countries, as well as the overview of already
existing ranking systems and studies in Europe, demonstrated a need to establish a
common and easily understandable new ranking system for environmental pressures, that
could give information on the existing situation with respect to mine waters and be used
for assessments and comparisons on multicountry level and catchment basis. The
proposed system uses and combines two main parameters characteristic to the mine site
or a set of small mines polluting a certain water course – the flow rate of the emissions
and its qualitative character expressed by the maximum value, how many times any of
the environmental standards (maximum permissable concentration) is exceeded. These
two parameters can be combined into one – pressure factor (PF), defined as log(number
of times standard exceeded) + log(emission flow rate, m3/day). The data are expressed on
a special plot, the five categories A…E define the number of times of the standard
exceedance (A – more than 1000 times; E – not exceeded), the classes are also dependent
on the flow rate. The available information and estimated parameters for different mining
sites in Central and Eastern Europe were compared on a single plot, showing the
differences of MPC exceedance and flow rates between emissions generated by the larger
and smaller scale mining activities of different commodities.
Introduction
Mine accidents in Aznacollar, Spain in 1998, where a damburst poisoned the
environment of the Guadiamar river, and the Tisza pollution caused by a cyanide spill
following a damburst of a tailings pond in Baia Mare, Romania in 2000 increased public
awareness of the environmental and safety hazards of mining activities in Europe. In mid2001, Joint Research Centre of European Comission started a project ‘Inventory,
Regulations and Environmental Impact of Toxic Mining Wastes in Pre-Accession
Countries’ (PECOMINES), one of the objectives of which was to collect and analyse
information on hazardous mine sites and mine wastes in Central and Eastern European
Candidate Countries.
A prerequisite for the comprehensive overview of the existing problems is a set of
criteria, according to which the comparisons on multicountry level could be made. The
assessment of waste generation showed, that in many Candidate Countries (Czech
Republic, Estonia, Bulgaria, Romania, Poland, Slovakia), the waste produced during the
extraction and processing of the mineral resources ranks first both in quantity and
creating environmental problems. The number of sites depended on the detailness of the
inventories carried out on the national level and the total number reaches many tens of
thousands, for example the Slovakian inventory only included 17260 sites. However,
there were no commonly accepted criteria, according to which the preliminary screening
of the huge number of the sites could accomplished in order to distinguish and compare
the set of most hazardous ones in one country with those in another.
When comparing the situation in different countries, a basic question came forward –
using which criteria it could be feasible to convert intuitive understanding of the ‘worst
cases’ in different countries having a different impact to environment by many orders of
magnitude (eg gypsum mines in one and very large metal mines in another country) –
into a comprehensive ranking system. This paper summarises the efforts of some
previous mine sites inventories in Europe, analyses the results of the PECOMINES
questionnaire answers and proposes a new methodology for comparative assessment and
ranking of mine sites with respect to hazardous mine water emissions.
The proposed methodology is envisaged to contribute to one part of the overall risk
assessment – characterisation of the pressures through continuous water emissions, and
does not consider the other problems related to mine sites, such as slope stability and onsite soil contamination.
Materials and methods
A multisource approach was used to develop a comparative assessment methodology,
including
- a review of previous comparative studies and methodologies in Europe
- analysis of the information gathered by questionnaire approach
- hydrochemical analysis of the test sites.
In a number of recent multicountry reviews, the source characterization that should be the
first step in the complete procedure of risk assessment (Figure 1) has been accomplished
on the basis of the amounts of mined commodities and/or disposed waste. The problem
is, that neither of those would give correct prediction of the water pollution related
environmental impacts even in the right order of magnitude. A small mine of sulphides
from a quartzite host rock producing pH 1-2 leachate and a large brown coal mine with
limestone dominating in the overburden with pH 7-8 leachate could be just two examples,
why the exercise fails.
CONTAMINATION
SOURCE
CONTAMINANT
IDENTIFICATION
FATE AND
TRANSPORT
EXPOSURE
ASSESSMENT
TOXICITY
ASSESSMENT
RISK CHARACTERISATION
A logical way forward that has been suggested and
developed, is a geoenvironmental model of a mineral
deposit that provides information about geochemistry and
its variations of a particular deposit type, and geochemical
variations associated with wastes and effluents (Plumlee
and Nash 1995). When becoming a major tool for
environmental assessment in a mine planning process, the
uncertatinties related to effluent quality of a particular
deposit type still remain, as the number of parameters that
control effluent formation and transport is still very large.
Therefore, for already existing sites, the association
between the magnitude of the water pollution related
environmental impacts and the deposit types is also not
straightforward, keeping in mind that the problems are
already there and the number of sites is estimated at many
tens of thousands.
Approaching the risk assessment procedure from the other
side – identifying all possible pathways and targets and
assessing the existing and potential damage – requires
development of a large number of different criteria together
with their weighting factors. As this has been already done
in many countries separately, any harmonization of these
Figure 1. Generalised scheme
of the steps of risk assessment
methodologies is a cumbersome task. The categories ‘high risk’ and ‘low risk’ in
different countries fully depend on the character and magnitude of the existing problems,
and are often related to the opinions of local experts.
The underlying assumption in the development of the screening methodology states, that
qualitative and quantitative characterization (measurement data or estimation) of the
hazardous water emissions makes it possible to relate pollution potential to the possible
set of environmental impacts. The justification of this statement is based on the
differences in these emissions – both in flow rates of the streams and concentrations of
different contaminants – by many orders of magnitude. Thus, even a rough estimation
including certain uncertainty factor becomes a useful information, making quantitative
comparisons possible.
Review of previous efforts
The simplified scheme of the sources for hazardous water emissions from the mine sites
is presented on Figure 2. As a whole, a mine site can be considered as more or less
complicated pattern of one, some or all these areas. The scheme does not include some
more rare cases, such as in-situ leaching facilities and ex-situ hydrometallurgical leaching
plants.
The emissions leaving the site and entering the catchment are impacting surface water
bodies, groundwater, soils and sediments, these systems becoming both targets but also
pathways. The final targets could be roughly grouped into human health-material values
and ecosystems-protected areas.
Referring to this schematic approach, it is possible to define the scope and describe the
content of a number of the previous multicountry and country-level comparative
assessment efforts, demonstrated in Table 1. The descriptions do not attempt to provide a
comprehensive overview of all existing efforts, but to demonstrate, what are the different
efforts based on and how different the approaches are. The information was mainly
collected on inventories of closed and abandoned mine sites. The number of these sites is
very large and the information usually limited.
TAILINGS
MINE VOIDS
WASTE ROCK
BACKFILL
WASTE
MANAGEMENT
FACILITIES
CONTAMINATED SOIL
AND WATER
MINE SITE
SURFACE
WATER
GROUNDWATER
SOILS AND
SEDIMENTS
SOURCE
PATHWAY
TARGET
HUMAN
HEALTH
MATERIAL
VALUES
ECOSYSTEMS
PROTECTED
AREAS
CATCHMENT
Figure 2. Simplified scheme of the source-pathway-target approach in mine and quarry sites
context.
Table 1. Examples of the previous and on-going efforts to tackle mine sites problems
Effort
Scope
Description
Results
Multicountry efforts
The Multi
124
uranium Compilation of an An
unique
systematic
Country
objects in 9 inventory of the approach for determination
PHARE
CEEC
existing situation; of individual or/and group
PROGRAMME countries, incl implementation of objects; collecting, validation
– Remediation
mine
sites pilot
projects; and
assessment
of
Concepts For
(Albania,
supporting
co- information for liabilities and
The Uranium
Bulgaria, Czech operation between impact on environment;
Mining
Republic,
the
involved implementation of unique
Operations in
Estonia,
countries
scale for ranking and
CEEC (MCP)
Hungary,
prioritization of objects in all
(Tabakov 2002) Poland,
participating countries, using
Romania,
a specially designed system
Slovakia,
for ranking; determination
Slovenia)
and implementation of Pilot
Projects
A preliminary metal mining confrontation of the recommendation was made
risk inventory areas
and mine site locations to use country-by-country
of toxic waste tailings lagoons with
protected approach towards all data
storage sites in in EU countries wetlands (Ramsar owners, including national
EU
countries
convention sites), authorities, counties, local
launched
by
as
particularly authorities and NGOs. It was
WWF
after
vulnerable
to also recommended, that
Aznacollar
pollution
from analysis of satellite remote
accident (Sol et
mining activities
sensing data could speed up
al 1999)
this process considerably
Management of Quantitative
a
questionnaire The rough estimation of
mining,
estimation of approach
in mining waste in different EU
quarrying and the
mining combination with countries, schemes of typical
ore-processing
waste in EU calculations based hydrogeological settings for
waste in the countries
on World’s average waste management facilities.
European
production-waste
Union,
the
materials ratios for
study
made
different
after Baia Mare
commodities
accident for DG
Environment by
BRGM (BRGM
2001)
The Regional Sites of highest Based
on
the Among the hot spots related
Inventory
of accident risk in national
to various industries, 19
Potential
Tisa Catchment information
mining spots were assessed
Accidental Risk on
the provided, 3 risk as at high risk in Romania
Spots in the territories
of
Tisa Catchment Romania,
Area by the Hungary,
International
Ukraine
and
Commission for Slovakia
the Protection
of the Danube
River and Zinke
Environment
Consulting
(ICPD, 2000)
Single country efforts
BULGARIA – concentrated
BGP,
BGPE towards
the
(Tabakov 2002) problems
related to the
uranium
production
CZECH
REPUBLIC
Impact
of
Mining on the
Environment
(Reichmann
1992)
1:500000 scale
map of Czech
Republic with
explanatory text
and legend
categories
were
established,
the
high risk category
being defined as
information based
indication for direct
or indirect high
accident
risk
(existing leakage
etc.).
(16 tailing deposits/ponds, 3
mines), 1 in Slovakia and 1
complex of reservoirs with
mine and industrial metal
sludge in Hungary.
a detailed inventory
with site specific
approach,
but
without
national
standards and real
experience in some
cases.
identification of objects,
collecting of past data for
inventory of liabilities, field
measurement and samplings
(water, soil, rock), laboratory
test
of
samples,
risk
assessment (site specific and
ranking system), grouping of
objects, development of
complex programme for
remediation
The impact of factors was
expressed in 3 categories:
high risk, low risk and no
risk, based on expert
estimations. Altogether, 169
sites and their different risks
were presented on the map.
The quantitative criteria for
different risk categories were
not established.
Using
the
geological
map
with
deposit
boundaries
and
mining areas as a
basis,
a
methodology
assessing
the
individual impacts
of 13 categories
was established
POLAND,
GeoThe
mines
Polish
environmental
presented on the
Geological
maps of the maps are assessed
Institute (Dr M. scale 1:50000, site-specifically
Gientka,
the basis is a into
nonpersonal
landuse map.
conflicting,
communication)
conflicting
and
very
conflicting
categories with the
surrounding
environmental
system, settlements,
The 1:50000 scale maps
provide a basis for solving
the problems on local scale,
case-by-case
PORTUGAL
Program
(Da
Silva covering
Daniel 2002).
abandoned
mines
all
SLOVAKIA
All active and
(Janova
and old mining sites
Vrana 2002)
SWEDEN
Is orientated to
Swedish EPA local
and
report ‘Methods regional
protected territories
and objects, etc
The ranking of the
mine
sites
regarding the safety
and environmental
problems, including
different weighting
factors for mine
safety, waste data
(volume, stability
and
chemistry),
chemical impacts to
soil and water,
visual impacts and
landscape,
and
human
presence
and activities in the
vicinity.
registration,
inventory
and
evaluation
of
present
(active)
mining sites of raw
materials
- 266
localities,
complex inventory
of old mining sites
– 17260 localities,
inventory
and
evaluation
of
impacts
of
all
mining sites on
environment,
preparation of state
monitoring of the
most
risky
localities of mining
sector,
proposal
and
realisation
of
remediation
activities
A contaminated site
is defined as a
landfill site or area
The final results ranked the
sites into:
Degree 4 – High hazards
Degree 3 - Medium hazards
Degree 2 – Low hazards
Degree 1 – Negligible
hazards
localities were categorised
into 3 categories with uniqe
methodology using different
weighting factors,
I category –remediation is
required as very acute step
II category –transitional
position, not so critical or
requires supplementary
investigation to clarify
situation (with possibility to
re-categorise the mining
site);
III category –apparently low
or minor impact on human
health, environment and
estates
Based on ranking system, the
I. category (and another three
localities of the II. category)
were denoted as “hot spots”
for which the monitoring
system is being developed.
Definition of the classes of
current conditions – 10 times
exceedence of guidance
for Inventories
of
Contaminated
Sites’
(Swedish
Environmental
Protection
Agency 2002).
authorities to
make accurate
assessments of
environmental
quality on the
basis
of
available data,
thus providing
a more solid
foundation for
environmental
planning
and
the
establishment
of
environmental
objectives
UNITED
KINGDOM
(Jarvis
and
Younger 2000).
national dataset
of the damage
caused
by
abandoned
mine discharges
of
soil,
groundwater
or
sediment, which is
contaminated by a
point source in the
extent that the
concentrations
significantly exceed
local or regional
background levels.
The assessment of
the sites is based on
environmental
quality criteria –
hazard assessment
based
on
hazardousness of
the
chemicals,
contamination level
comparing
the
current conditions
with
reference
values, amount and
volume of the
contaminated
material, potential
for migration and
consequences
–
human sensitivity
and
protection
value.
Method of UK
National
Rivers
Authority (now the
Environment
Agency):
the
severity
of
environmental
impacts
is
measured
sequentially in six
categories:
1.Area affected (by
deposition of metal
precipitates,
assessed visually);
values for state describes the
sites
as
very
serious
(uppermost class), and 25
times
exceedence
of
reference values of impact
define the sites as belonging
into the class of very large
effect of point sources (also
uppermost class)
Indicates that some 400 km
of watercourse are currently
degraded by abandoned coal
mine discharges, with a
further 200 km contaminated
by abandoned metal mine
discharges. Within these UK
totals, well over 90% of the
total polluted drainage turned
out to be accounted for by
discharges from polluted
mine voids rather than from
old mine waste depositories.
The extrapolation in the lack
of European data suggests
2.Length affected
(m);
3.Substrate quality
and
salmonid
reproduction;
4.Iron deposition
(the intensity of
discoloration,
assessed visually);
5.Total
iron
concentration;
6.pH,
dissolved
oxygen
concentration and
aluminum
concentration.
After this ranking,
benthic
macroinvertebrates
are
used
to
determine
water
classes.
that the total length of
watercourses polluted by
mine drainage in the present
EU may well prove to
exceed 5000 km, with
Candidate Countries adding
their contribution (Younger,
2002). .
The comparison of international and country specific efforts shows the basic difference in
approaches.
Until now, multicountry efforts have been either approaching a certain sector (eg uranium
mining), concentrating on certain elements of mine sites (eg tailings ponds within a
catchment), or just roughly assessing the amount of waste. At the same time, all countries
have established their own approaches and methodologies, some of them illustrated in
Table 1. The following basis can be separated for the assessment:
- concentrating on the most relevant problem area (eg uranium mines in Bulgaria);
- map-based overviews (eg Czech Republic, Poland);
- unique ranking schemes and action plans (in all countries).
The sites ranked by different systems into high hazard, high risk, class I, very large effect
etc are not comparable with each other, and no synoptic picture over the system can be
established. For many of the top-ranked sites, the action plans are already prepared and
currently under implementation. The approach used in one country cannot be easily
converted into another.
Analysis of the questionnaire results
In the frames of the PECOMINES project, an international steering group was
established, including 18 members of the ministries and geological surveys and institutes
in 10 Candidate Countries. The experts were asked to submit filled questionnaires with
the information on the most severe problem sites in their countries, based on their expert
judgement. Based on the information submitted and environmental impacts analyses of
the test sites of the project, 37 ‘hot spots’ were defined and it became possible to define
more clearly, what is meant under the term ‘hot spot’ by expert judgement. Four different
categories were distinguished:
(1) Sites generating hazardous emissions of contaminated water with negative
impacts;
(2) Large contaminated territories with cavities, waste heaps and/or tailings ponds;
(3) Tailings ponds with large volumes of contaminated water or heaps with instable
slopes, having a risk the material being accidentally released;
(4) Sites with hazards qualitatively recognised but lacking quantitative information.
The results of the hot spots inventory show, that determination of the hot spots is local
knowledge based and impact-led, and cannot be preliminarily screened by different
filters. Even if 35 of the 37 sites are metal, uranium and fossil fuels mining sites, 2 are
actually industrial minerals (phosphate and quartzite) mines, the reason of inclusion being
that the overburden contained sulphides, leading to similar impacts of acid drainage as
those occurring due to metals and fossil fuels mining. Thus, although commodity mined
is in large extent determining the character of impacts, there are exceptions depending on
deposit geology.
Also, there is no direct linkage between the status of the mine and if the mine site is
considered to be a hot spot or not: approximately 1/3 of the hot spots are active mines, the
others closed or abandoned. It should be pointed out, that ‘closed’ mine status does not
necessarily mean, that the problems are less, because of the two reasons: in the past, the
environmental standards were considerably lower, and secondly, the competence of the
authorities could have been rather limited so that the problems in longer term after the
closure have been not avoided.
The problems in different countries differ by many orders of magnitude. Lithuania has no
mines that could cause any significant damage to the environment, and Latvia has several
small gypsum mines with small scale impacts. All other 8 countries are facing severe
water pollution problems, still making it possible to rank the 10 countries into 3 groups:
Group 1 – hazardous water emissions from mine sites a top national priority
Bulgaria – uranium mining
Czech Republic – uranium mining (declining), metal mining (stopped in the beginning of
1990-s), coal mining
Poland – coal mining, metal mining (processing waste of copper, zinc and lead)
Romania – metal mining, coal mining
Slovakia - metal mining (stopped in the beginning of 1990-s), coal mining
Group 2 – problems exist, but contamination by mining industry not in the top on the
national scale – the cases are solved on an individual approach basis
Estonia – phosphate mining (stopped in the beginning of 1990-s), oil shale mining,
uranium processing waste
Hungary – closed uranium and copper mines, red mud at alumina plants
Slovenia – uranium processing waste, brown coal and metal mining
Group 3 – problems are insignificant on national scale
Latvia
Lithuania
Water quality values for quantitative comparison
European Union is on its way to agree environmental quality standards for water bodies
in the framework of the implementation of the Water Framework Directive 2000/60/EC,
and to develop the standards for solid phases, such as soils and sediments. As these and
also other chemicals environmental quality standards are not still available, a set from
different sources was developed for methodology testing. The values given in the Tables
below are Maximum Permissible Concentration (MPC) values that have been estimated
on scientific basis, indicating that the concentration of a substance or a value of a
parameter
- has no expected effect to be rated as negative for ecosystems,
- has no expected effect to be rated as negative for humans (for non-carcinogenic
substances),
- has calculated probability loss of human life through cancer risk less than 10-6 per
year.
The MPC values should not be mixed with target values, that are set at the level of
negligible concentration and should be achieved as the environmental quality in longterm. The target values include often additional safety margin, being up to 2 orders of
magnitude less than MPC’s. However, the MPC’s are less than intervention values, that
indicate a serious or imminently serious decrease in the functional properties of soil,
sediment or water for humans, plants and animals.
The estimations of MPC’s based on the analyses by scientific communities in different
countries are somewhat different, but not so significantly, that this could change the overall picture regarding mine and quarry waste emissions, where in the extreme cases, the
standards are exceeded by 4-5 orders of magnitude.
For the range of parameters, elements and substances relevant for screening mine waste
problems, the existing drinking water standards presented in 98/83/EC are very similar to
surface water MPC’s; the main 2 exceptions are Cu and Zn, for which drinking water
standards permit much higher concentrations because of Cu and Zn pipes used. For the
elements and substances known as being harmful but not limited by EC regulations, the
WHO, Dutch, Belgium, Swedish and German quality standards were accounted for
(Environmental quality standards in the Netherlands… 2001; Barkowski et al. 1993;
Swedish Environmental Protection Agency 2002). Although some of the Candidate
Countries may have different standards used at the present, to get the comparative picture
and, also, to give understanding how EC accession changes the pattern, the uniform
values are used. The values are presented in Table 2.
Table 2. Maximum permissible concentration values used for testing the methodology.
SURFACE WATER AND GROUND WATER
pH
suspended solids
ammonium
nitrates
nitrites
total phosphates
COD
conductivity
chlorides
sulphates
fluoride
total cyanides
Aluminum (Al)
Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Manganese (Mn)
Iron (Fe)
6.0-8.5
50 mg/l
0.5 mg/l
50 mg/l
0.5 mg/l
1 mg/l P
30 mg/l
2500 S/cm
200 mg/l
250 mg/l
1.5 mg/l
0.05 mg/l
0.2 mg/l
12 mg/l
200 mg/l
50 mg/l
50 mg/l
0.5 mg/l
0.2 mg/l
Other metals (g/l)
Antimony (Sb)
Arsenic (As)
Barium (Ba)
Beryllium (Be)
Cadmium (Cd)
Chromium (Cr)
Cobalt (Co)
Copper (Cu)
Lead (Pb, total)
Mercury (Hg)
Molubdenum (Mo)
Nickel (Ni, total)
Selenium (Se, total)
Silver (Ag)
Tin (Sn)
Vanadium (V)
Zinc (Zn, total)
5
10
250
0.2
5
50 (total)
20 (total)
50 (total)
25
1 (total)
300
20
10
10
200 (total)
5
40 (total)
Radioactive elements
98/83/EC defines 6.5-9.5
98/83/EC
98/83/EC
98/83/EC nitrate/50+nitrite/3<1
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC
98/83/EC 2000 g/l because of Cu pipes
98/83/EC, 10 after 2013
82/176/EEC 98/83/EC
98/83/EC
98/83/EC
There are no European environmental standards for concentration of total U and Ra226 in
water, so US EPA standards were used.
Uranium
30 g/l
US EPA
Ra 226 & 228
15 pCi/l (0.56 Bq/l) US EPA
http://www.epa.gov/safewater/standard/pp/radnucpp.html
Hydrochemical analysis of selected hot spots
The concept of the comparative methodology has been developed on the basis of
PECOMINES project case studies in Slovakia and Estonia, and is illustrated here using
the example of Smolnik mine in Slovakia.
The Smolnik underground copper, iron, gold and silver mine is situated in the Slovenske
Rudohorie Mts, Eastern Slovakia, in the district Gelnica, Kosice Region, 4 km from the
town Smolnik. After more than 7 centuries of operation, the mining was stopped in 1990
and flooded, with negative ecological consequences four years later, in 1994, when the
water of Smolnik stream downstream from the mine and river Hnilec was acidified
causing large fishkill.
Nine years later, in 2003, the Smolnik stream is still receiving acid drainage from the
flooded mine at the rate so that more than 10 km of the streams is continuously polluted.
The continuous discharge of highly acidic leachate has the yearly average rate 15 l/s.
Based on the water analyses data of the main source (emission from the mine, averaged
data from 20 measurements between 1997-2001) and downstream from the source
(upstream water was found to have concentrations below all MPC’s), and comparison of
the concentrations with MPC’s, the specific graph was constructed, presenting the
potential of the emissions with respect to certain contaminants to pollute natural water
courses (Figure 4).
Emissions potential
1.E+05
1.E+04
times standard exceeded
Fe
1.E+03
1.E+02
Mn, pH, Al
Zn
Cu
SO4
1.E+01
1.E+00
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
1.E+11
Emission m3/day (1 m3/day = 0.0116 l/s)
Figure 4. Determination of emissions potential for the Smolnik site.
The vertical axis of the log-log plot describes, how many times the MPC value of a
particular contaminant in the emission is exceeded, and the horizontal axis gives the
value of measured or estimated quantity of the emission. The left bunch of dots describes
the emission from the mine, and the right one, the situation at the point 100 m
downstream from the source. The dilution factor in this case is 1:19.
During its downstream movement, the emission gets diluted both through mixing with
other streams, water in the stagnant water body (pond, lake, sea) or groundwater, and
through removal into solid phase within the catchment features (river sediments,
wetlands, soils, groundwater bearing rocks etc). With these considerations being most
important for site-scale studies, the number of parameters and variables to account for
gets so large that in the overall chain sourceemission pathwaytarget, related to the
poor quality of existing data, no adequate comparison of all the important factors on
multinational scale was considered to be possible at the moment. As the first step in
quantitative comparison of existing pressures, the concept of ‘the emission rate of the
contaminant most exceeding the MPC’ is proposed to characterize a site.
In Smolnik case, this contaminant is Fe, exceeding MPC by 3000 times, with Al, Mn and
pH following in the range of 400-650 times.
The point on the graph, characterizing the Smolnik site, has in such determination the
center at 3000 times exceeded and 1700 m3/day, with variation 1500-6000 times
exceeded and 850-3400 m3/day on the log-log plot.
The characteristic diagonal lines on the plot express the ‘worst case’ of possible extent of
the polluting waters from the source within the catchment, ie the case where the
environmental system downstream is not able to remove the contaminants from the flow
and the only decrease in exceeding the standard is through dilution and dispersion. This
can be illustrated through plotting, for example, the advancement of cyanide spill of the
Baia Mare accident (that was basically a 1-day event) on the same graph, with river
systems not having considerable capacity to remove cyanide (Figure 5).
Emissions potential
1.E+05
AURUL POND
CALCULATED FOR 1-DAY
RELEASE
times standard exceeded
1.E+04
1.E+03
SZAMOS
1.E+02
TISZA
1.E+01
1.E+00
1.E-01
1.E+00
DANUBE
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
1.E+11
Emission m3/day (1 m3/day = 0.0116 l/s)
Figure 5. Movement of Baia Mare cyanide plume downstream (averaged 1-day values,
times standard exceeded 1 day only; data from BMTF, 2000).
A method for calculation of pressure factors and ranking into categories and classes
The categories given by letters represent the qualitative hazardousness of the emissions.
Category A – MPC exceeded by more than 1000 times
Category B – by 100 – 1000 times
Category C – by 10 – 100 times
Category D – MPC exceeded by up to 10 times
Category E – MPC not exceeded
Combined with numbers, the combination represents both the emission rate and
qualitative hazardousness of the emission.
A parameter PF (pressure factor) is defined as log(times standard exceeded) +
log(emission rate, m3/day) on the condition that log(times standard exceeded) > 0, and its
value has a meaning of a potential to pollute 10PF m3/day of pure water, assuming that
dilution is the only certain mechanism for decrease of the value of the exceeded MPC
until the standard is not exceeded any more. If log(times standard exceeded) < 0, the
emission stream belongs to category E.
For example, if MPC is exceeded by 300 times and emission rate is 2500 m3/day, the
parameter PF = log(300) + log (2500) = 2.48 + 3.40 = 5.88, meaning that the emission
from this source has a capability to pollute 105.88 m3 of pure water per day.
The proposed system characterises the pressures only and does not consider the multiple
set of contraactions to the pressures – neither natural buffering nor man-made systems, in
the same way as Richter scale describes the magnitude of earthquakes only, not the
impacts. Nevertheless, Richter scale is used as a certain, well-known and uniformly
understood parametric scale, and magnitude 4 earthquakes are never as destructive as
magnitude 8 ones.
Based on that, the classes are set to characterize the emissions potential (the emission
given in the example made above belonging to the class B3), as presented on Figure 6.
Emissions potential
1.0E+05
Times standard exceeded
1.0E+04
A1
A2
A3
A4
A5
A6
B1
B2
B3
B4
B5
B6
C1
C2
C3
C4
C5
C6
C7
C8
D1
D2
D3
D4
D5
D6
D7
D8
D9
E
E
E
E
E
E
E
E
E
1.0E+03
B7
1.0E+02
1.0E+01
1.0E+00
E
1.0E-01
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07 1.0E+08 1.0E+09 1.0E+10 1.0E+11
Emission m 3/day (1 m 3/day = 0.0116 l/s)
Figure 6. Classes of the pressures
The classification system can be also applied for a particular contaminant only. For
example, the data of the Smolnik site presented on Figure 4 make it possible to determine
categories and IH values for pH and different contaminants:
Emissions 1300 m3/day (1 point source)
pH 3.2, SO4 7000 mg/l, Al 85 mg/l, Mn 320 mg/l, Fe 580 mg/l, Cu 3.8 mg/l, Zn 7 mg/l
MPC exceeded 600 times for acidity, 30 times for SO4, 430 times for Al, 640 times for
Mn, 2900 times for Fe, 76 times for Cu, 180 times for Zn
Point on the graph: 1300 m3/day, 2900 times exceeded, Class A3
Classes for all major contaminants:
acidity – Category B, PF = 5.89, Class B3
SO4 – Category C, PF = 4.59, Class C3
Al – Category B, PF = 5.74, Class B3
Mn – Category B, PF = 5.92, Class B3
Fe – Category A, PF = 6.57, Class A3
Cu – Category C, PF = 4.99, Class C3
Zn – Category B, PF = 5.37, Class B3
The practical application of this method is to clearly distinguish the inputs of particular
contaminants on the catchment basis and to work out intervention strategies.
COMPARATIVE PLOT OF MINE SITES
As an example of the assessment of different sites, a plot was constructed that expresses
extrapolated information obtained by the PECOMINES questionnaire. For most of the
sites reported in PECOMINES questionnaire, no quantitative data on emission volumetric
rates were found to be available (except for 3 sites studied within the project itself:
Smolnik and Banska Stiavnica in Slovakia, and Maardu in Estonia). However, the area of
the site, being a catchment for the emissions, was assumed more ore less accurately to
predict the magnitude of emissions. In the calculations, infiltration rate 500 mm/year was
used for all sites, with using on the presentation of the data on the graph the uncertainty
factor 2 on log-log plot (2 times less or 2 times more, 250 – 1000 mm/year).
The quality data on emissions, that were available for 21 sites, were extrapolated to
characterize all the volume of measured or estimated emission. Also here, for
representation of the orders of magnitude of problems magnitude and significance, as no
reference to the measurement quality could be provided, the uncertainty factor 2 was
used, with the characteristic point describing 2 times lower or higher concentration with
its size.
Emissions potential
1.0E+05
Banska
Stiavnica
1.0E+04
Smolnik
Times standard exceeded
big and very big
copper mines
1.0E+03
smaller metals
and uranium mines
1.0E+02
uranium
mining regions
Maardu
1.0E+01
1.0E+00
1.0E-01
1.0E+00
lignite, coal and oil shale
mining regions
separate tailings ponds
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
1.0E+09
1.0E+10
1.0E+11
3
3
Emission m /day (1 m /day = 0.0116 l/s)
Figure 7. The graph of the assessment of emissions potential of the mine sites hot spots in
EU Candidate Countries.
The fields presented on the graph are
- big copper mines: Rosia Poeni in Romania; Elatzite, Medet and Pangjuriste in
Bulgaria; Smolnik in Slovakia – main contaminant exceeding MPC 500-10000
times either Cu, Fe, sulphate or acidity; ranking A3, A4, B4;
- smaller mines: Banska Stiavnica, quartzite mine in Slovakia (acidity, Al); Recsk,
metals mine in Hungary (acidity, Fe); Mecsek uranium mine in Hungary
(uranium); ranking A2, B2;
- uranium-mining regions: Eleshnitsa and Buhovo in Bulgaria, main contaminant
either uranium or sulphate; ranking C5;
- lignite, coal and oil shale mining regions in Romania (Motru), Poland (Upper
Silesian Coal Basin) and Estonia (oil shale mining region); main contaminants –
sulphates, exceeding MPC upto 3 times; ranking D5, D6;
- separate tailing ponds (plot does not include the risk of dam failure) – main
contaminants As, U, Fe, acidity; ranking C2, C3, D2, D3, D4;
- Maardu phosphate mine in Estonia (MPC exceeded up to 30 times, main
contaminants Cu, Zn, Ni); ranking C4.
It should be pointed out, that the diagonal lines can be interpreted as pressure factor
isolines for environmental pressures that the site creates to the environment though water
emissions. With increasing pressures towards the right upper corner, the difference in
pressures between 2 consecutive lines is 10 times.
On the same isoline, the sources at the upper left corner are more concentrated and can be
more efficiently treated.
The methodology of ranking and plotting the emission streams is also proposed to be
used as an effective tool for river basin management. Similar concept has already been
used for identification and visual presentation of main pollution sources within a
catchment in South Africa (P. Younger, personal communication).
The overview plot presented on Figure 6 shows also the severity of the problems – there
are many mine sites in Central and Eastern Europe that have a potential to pollute more
than a million m3 of water per day. The reliable quantitative data on those are still
lacking, the plot was constructed using the collected available data and estimations.
Obviously, in most of the cases, the potential is not realised at full extent – buffering,
adsorption, reduction, precipitation etc are just some of the mechanisms of contaminants
removal from the water phase. However, especially in case of heavy metals, these
mechanisms solve one problem, but create another – such as contaminated soils and
sediments, impacts to the ecosystems etc. Therefore, the characterisation of pressures
remains informative.
Conclusions
The order of magnitude of environmental pressures of a mining site to the catchment
through mine water emissions can be described by a simple assessment of two parameters
- the quantitative yearly average flow rate of the emissions and the number of times the
maximum value by which environmental standard (MPC) of any contaminant is
exceeded.
These two parameters can be combined into the single parameter – pressure factor (PF),
defined as log(times standard exceeded) + log(emission rate, m3/day) on the condition
that the number of times standard exceeded > 0, expressing the capability of the
emissions from given source to pollute 10PF m3 of pure water per day.
With the system of categories and classes, each site can be ranked, expressing
hazardousness of the emissions with categories A…E and rates of the emissions with
classes 1…8.
Testing the proposed methodology with extrapolated results of the PECOMINES
questionnaire shows, that despite the large uncertainties in the collected information,
mine sites of certain commodities tend to concentrate in certain areas on the test plot.
Thus, characterisation of the pressures through the ranking, plotting and isohazard system
is informative in the same way as Richter scale on earthquakes and could be used as one .
multicountry level – although the problems in each country are well-known, the
methodologies of assessment and scales of significance are too different to make
comparisons possible. The proposed methodology makes it possible not only to define,
which pressure could be more significant, but to compare the orders of magnitude of the
significance. For example, if the comparison of the ‘worst cases’ in particular regions is
started by determination of D2 site in one region and A4 site in the other, the difference
in pressures of approximately 5 orders of magnitude is an obvious and informative
assessment.
The sites that rank into the same isohazard category, such as A2, B3, C4, D5, point out
the feasibility of possible actions. The emissions of the A2 site are approximately 3
orders of magnitude more concentrated and less voluminous than those of D5, and could
be more effectively treated. Within the river basin management, the methodology can be
used for prioritisation and visualisation of the problems for the decision-makers.
Acknowledgements
The paper was prepared using the information gathered and analysed by Erik Puura
during the mission as a national detached expert at the EU Joint Research Centre Institute
for Environment and Sustainability, Soil and Waste Unit, in the frames of the
PECOMINES project (http://viso.ei.jrc.it/pecomines_ext/index.html). The authors are
greatful to the project’s steering group members from Bulgaria, Czech Republic, Estonia,
Hungary, Latvia, Lithuania, Poland, Romania, Slovakia and Slovenia.
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