Summary of Water Monitoring Data from Environmental Audit of Automotive
Businesses
This report outlines the results of the first round of monitoring associated with the
environmental audit of automotive industries in the Sutherland Shire. Samples were
collected on the 8th, 10th -15th July 2002, in the morning (usually between 6 a.m. and
7.30 a.m.) and in the afternoon (usually between 12.30 p.m. and 2.30 p.m. ). Samples
were analysed for suspended solids, chemical oxygen demand, ammonia, total
nitrogen, total kjeldahl nitrogen, total phosphorus, a range of metals, grease, and
nitrates. The samples were analysed by a NATA registered laboratory.
The weather for the entire sampling week was dry. This means that water samples
taken represent ‘base flow’.
Results:
Complete results and time series graphs from the sampling round can be found in
Appendix 1.
Table 1: Assessment Criterion
Indicator
Ammonia
COD
Oil & Grease
Total Nitrogen
TKN
NOx
Total Phosphorus
Total Sus Solids
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Chromium
Cobalt
Copper
Lead
Manganese
Molybdenum
Nickel
Selenium
Tin
Vanadium
Zinc
Units
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
Mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
Criterion
0.03
2
5
0.75
N/A
0.045/0.15
0.1
10
N/A
0.05
1
N/A
1
0.005
0.05
0.15
0.005
0.005
0.1
0.05
0.1
0.01
N/A
N/A
0.05
Comments
Value for BOD used
Value for estuaries/Lowland rivers
Insufficient data for guideline development
Recreational water quality, ANZECC & ARMCANZ, (2000)
Recreational water quality, ANZECC & ARMCANZ, (2000)
Insufficient data for guideline development
Recreational water quality, ANZECC & ARMCANZ, (2000)
Recreational water quality, ANZECC & ARMCANZ, (2000)
Recreational water quality, ANZECC & ARMCANZ, (2000)
Protection of 80% of species in marine water
Recreational water quality, ANZECC & ARMCANZ, (2000)
SCA data
Recreational water quality, ANZECC & ARMCANZ, (2000)
Recreational water quality, ANZECC & ARMCANZ, (2000)
Insufficient data for guideline development
Insufficient data for guideline development
A range of assessment criteria has been used for comparative purposes, as shown in
Table 1 above. It is worth noting, however, that these values are used purely as a
comparative tool, as it is difficult to relate the values in the ANZECC document to
stormwater. Furthermore, there are no guidelines for several of the metals in the
current ANZECC guideline document (ANZECC & ARMCANZ, 2000). In these
cases, the precautionary principle is applied, and the detection limit of the method
(0.005 mg/l) is considered to be the guideline value. A range of values characteristic
of Shire stormwater is also included by way of comparison in Appendix 2.
1. Oak Rd (Control; Residential Catchment)
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Ammonia generally less than detection limit.
Copper lead and zinc compared well with levels considered to be characteristic of
Shire stormwater, and well below ANZECC criteria. Other metals below detection
limits, except boron, barium and manganese. These were all at levels considered
characteristic of stormwater, and below the guidelines in Table 1.
Total nitrogen often above guidelines, made up mostly of organic and oxidised
species.
Total phosphorus on the whole less than the guideline. A consistent increase noted
from Friday onwards, with Sunday & Monday afternoons exceeding the criterion.
Suspended solids mostly below the guideline, and levels were characteristic of
Shire stormwater
Grease was fairly consistent through the week with the exception of the Friday
p.m. It was often above the guideline, and levels were high when compared to
Shire stormwater. The high level on Friday afternoon is difficult to explain
COD levels consistently below the guideline in the mornings, but higher (around
10 mg/l) in the afternoon
The majority of parameters showed no real variation from a.m. to p.m., but p.m.
COD data were generally consistently higher than a.m..
There is no real evidence of a pattern to data over the week, nor a cycle, however
there would need to be further sampling to confirm this.
Nitrogen species and suspended solids high at the weekend. This may be
explained by increased residential activity at weekends, such as car washing,
hosing surfaces or gardens.
2. The Boulevarde (Kirrawee Industrial area)
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Ammonia often below the detection limit in the afternoons. Mornings often higher
than afternoons, with Friday morning showing an extreme level (9.8 mg/l) and
remaining quite high subsequently.
A more diverse range of metals was detected, but generally in levels below the
guidelines. Boron, barium, zinc and molybdenum peaked on Thursday afternoon.
Zinc levels often above the guideline but comparable to other Shire stormwater.
Copper also comparable to Shire stormwater.
Total nitrogen all above guideline and variable, with very high peaks (>10 mg/l).
At the highest end of TN concentrations in Shire stormwater.
Extremely high total phosphorus concentration (12mg/l) on first Monday
afternoon. Suggested that, as the phosphorus can be considered to be soluble, nonparticulate and inorganic, that it may be the result of a spillage or dumping of
detergent or fertiliser. COD also very high for this sample, suggesting a chemical
source.
Suspended solids generally less than the guideline, with the exception of Wed
morning. This sample was the maximum at 16 mg/l, a low maximum for Shire
stormwater.
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Grease was generally above the guidelines, with high maxima reflecting the
prevalence of automotive industries.
Both morning and afternoon grease samples showed a fairly consistent gradual
incline through the week to Saturday. The difference between a.m. and p.m.
concentrations also increased during the week.
COD variable through the week, but some extreme levels were recorded (eg 440
mg/l on Thurs p.m. ). Afternoon samples consistently higher than morning. The
latter rarely exceeded 10 mg/l, while the range for afternoon was generally
between 10 and 100 mg/l.
3. Princes Highway (Kirrawee Industrial area)
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Ammonia generally below the detection limit; maximum of 0.6 mg/l not
excessive.
Copper exceeded criterion most afternoons, but not in the morning. Maximum
recorded on Sunday afternoon quite high by Shire standards
Levels of zinc less than the guideline were the exception, with most exceeding
Higher boron levels than other sites recorded; guidelines occasionally exceeded
Molybdenum exceeded guideline on one occasion
Most other metals below detection limit or below guideline
Total nitrogen, ammonia and oxidised species highest on first Monday; little
difference after Wednesday between a.m. and p.m. samples; most samples above
the guideline.
All but Monday a.m. phosphorus samples above guideline; morning samples quite
consistent but afternoon highly variable; very high maximum (19 mg/l)
Suspended solids compatible with Shire stormwater. Maximum of 82 mg/l not
excessively high by comparison; little difference between a.m. and p.m. ;
Grease levels generally above guideline. Morning data shows an apparent steady
increase over the week
COD concentrations >100 mg/l not uncommon; most samples 10 – 100 mg/l.
Highest levels in latter part of week and the weekend.
4. Railway Land, Kirrawee (Near Kirrawee Station)
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All but two ammonia samples less than the detection limit. Exceedence of
detection limit means exceedence of guideline.
Some manganese and cadmium samples exceeded guidelines, but were only
marginally over.
All afternoon and some morning copper samples were over the guideline
All zinc concentrations greater than the guideline, with the maximum being a very
high level (1.7 mg/l)
Lead levels often above the guideline, but the maximum value of 0.03 mg/l was
comparable to other Shire stormwater.
Total nitrogen levels all exceeded the guideline, but showed something of a
decline over the week
Total nitrogen apparently made up mostly of ammonia and organic nitrogen
Total phosphorus levels variable, but generally above guidelines and generally
high compared to other Shire stormwater
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Suspended solids rarely less than 20 mg/l and all samples over the criterion. High
maximum value at 160 mg/l.
Nearly all grease samples above the guideline, and levels were variable with no
pattern emerging.
Minimum COD was 60 mg/l, with most samples greater than 100 mg/l. Criterion
value is 2 mg/l. Afternoon COD generally higher than morning.
5 Taren Point Rd (Taren Pt industrial area)
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All ammonia samples were less than the detection limit, with the exception of the
Sunday afternoon, which had a concentration of 0.2 mg/l.
The majority of metals were in concentrations less than the detection limits, or
less than the criteria. Exceptions to this were:
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Boron, particularly in the afternoons, had levels well above the
guideline. All afternoon and all but 2 morning samples exceeded.
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Selenium samples from both morning and afternoon on Wednesday
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Zinc exceeded on several occasions during the week, including
Monday and Wednesday morning, and Thursday and Saturday
afternoons. Other zinc levels were below the guideline but quite
variable. The excedeences were not considered to be of great
significance, since the exceedence amount was only small.
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Lead levels from the first Monday morning and Sunday afternoon
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Nickel from Wednesday a.m. and p.m.
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Most copper concentrations were above the guideline, but within what
would be considered as typical for Shire stormwater.
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This was one of the few sites where arsenic was in detectable
concentrations.
All total nitrogen levels were above the guidelines, being between 1 and 5 mg/l.
Total phosphorus all above the guideline, with a maximum of 1.4 mg/l.
Differences between morning and afternoon samples not great
Suspended solids showed little difference between morning and afternoon samples
All suspended solids were above the guideline, with a maximum suspended solids
reading of 830 mg/l (extremely high). Afternoon samples showed a fairly steady
rise over the week.
Grease concentrations peaked on Saturday
Morning grease generally higher than afternoon
Consistently high COD, probably the highest in the program. Maximum of 520
mg/l was extremely high. Morning and afternoon samples variable
6. Box Rd (Taren Pt industrial area)
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Many samples in the extreme range for ammonia, with a maximum of 6.4 mg/l
Possible indication that there is an activity resulting in high ammonia taking place
overnight during the week and on weekend
Most metals less than the respective detection limits or guidelines, with the
following exceptions:
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Boron on the afternoon of the first Monday
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Manganese on the afternoon of the first Monday
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Selenium on the afternoon of the first Monday and Sunday, and in the
morning of the Wednesday
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Zinc was regularly over its guideline, particularly on Thursday, Friday
and Sunday, in both the morning and the afternoon. The values
recorded were consistent with other Shire stormwater.
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There was one exceedence of copper, on the Friday afternoon. All
other samples were below the detection limit
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Nickel exceeded on Wednesday a.m. and p.m.
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Lead exceeded on Thursday morning, Friday a.m. & p.m., and Sunday
p.m.. Most other levels were below the detection limit
On the whole metals not a concern at this site, but selenium levels were
interesting. Copper uncommonly low for stormwater in the Shire.
Total nitrogen levels all above guideline, with a high maximum of 14 mg/l
While ammonia levels were high, organic nitrogen also contributed significantly
to the total.
Total phosphorus was often over the guideline, but the maximum (0.57 mg/l) was
not extreme. Levels did not differ much from a.m. to p.m.
Suspended solids generally over the criterion, although the maximum level was
not extreme. There was something of an inverse relationship between morning and
afternoon, with the highest morning value corresponding with the lowest
afternoon, and vice-versa.
Grease samples generally above the guideline. Levels overall rose steadily during
the week to a peak on the Saturday. There was generally little difference between
a.m. and p.m. samples
COD levels generally very high, with only two samples less than the detection
limit. Maximum COD was 140 mg/l
7. Kumulla Rd (Small industrial complex)
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Ammonia below detection limits for all samples
Metals generally below the detection limits, or below the criteria. Exceptions
were:
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Copper was consistently below or marginally above the guideline in
morning samples, but afternoon samples were all over. A fairly
consistent rise was noted, to a peak on the Friday p.m. of 0.11 mg/l.
This was followed by a similar fall. The pattern is remarkably
symmetrical, and suggests that there may be a weekly cycle.
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Morning lead samples were mainly less than the detection limit.
Afternoon samples were also until the Saturday, when concentration
was 0.011 mg/l. It stayed at this level for the rest of the week.
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Zinc was consistently over the criterion, with the lowest level being
0.087 mg/l, and the highest 1.7. Afternoon levels were variable, but
morning samples had a relatively confined range of values.
Total nitrogen all above the guideline, and there seemed to be an inverse
relationship between a.m. and p.m..
Oxidised nitrogen was a significant contributor to the total
Total phosphorus levels all around the guideline except for Saturday samples
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Suspended solids were of a similar magnitude to Box Rd, with a maximum of 33
mg/l, and all but three samples less than the guideline value. Afternoon samples
were consistently less than 5 mg/l
Grease samples were of similar magnitude to Box Rd, with a maximum of 30
mg/l, and variable concentrations during the week. Morning samples were more
variable than afternoon.
COD at this site by no means near the extreme levels of other sites
Afternoon samples below the detection limit until Saturday, when the maximum
of 60 mg/l was recorded
Of all the parameters examined, the most consistently problematic appears to be
Chemical Oxygen demand. This is a measure described as: ‘the oxygen equivalent of
of the organic matter of a sample that is susceptible to oxidation by a strong chemical
oxidant’ (ANZECC & ARMCANZ 2000). This essentially means the potential
amount of oxygen required for oxidation reactions in the water sample.This was
chosen instead of biochemical oxygen demand, in order to give an idea of the possible
chemical pressure on oxygen concentrations in the samples rather than a measure of
biological (particularly bacterial) activity.
There does not seem to be patterns in the data, although it is difficult to tell from one
week. There was no real evidence of cycles of concentrations, and there was no
consistent relationship in most cases between morning and afternoon concentrations.
Furthermore, there was no real pattern in the peak levels of contaminants. For this
reason, the data is difficult to interpret. For example, a high grease level on Friday or
Saturday afternoon might mean end of the week washing down; but a peak on
Wednesday morning is not so easy to explain, and for this reason, further data from
the next round of sampling may go some of the way to improving that situation.
Another difficulty is that there were no wet-weather samples, and we can expect that
many parameters will peak in wet weather. Where high levels are experienced in dry
weather, it is reasonable to assume that activities such as hosing down forecourts or
workshops is taking place, and from the data it is possible this is happening on a
regular basis.
Some additonal information:
Uses for some of the lesser known metals:
Selenium:Toners for photocopiers (and photocopier parts); copper smelting; released
during coal & petroleum combustion; smelting & refining other metals; Used in the
production of glass, pigments, rubber, alloys, textiles, petrol, medical and therapeutic
compounds; photographics. Levels are usually around 0.02 mg/l in freshwater
Boron: Also used in glass manufacture; borax in detergents, fireworks, insulation
fibreglass; radio tubes; high tempeature abrasives; ultra high temperature gasketing;
soil conditioner; is not particularly toxic, and has lubricating properties like graphite.
Manganese: Steel making; construction; machinery/transportation
Molybdenum: Steel making; high temp & pressure tolerant alloys; aircraft parts;
forged car parts; electrodes; nuclear catalyst in petrol refining; electronics (filaments);
can be used as ultra high temp lubricant
Barium: Electronic components; metal alloys; bleaches & dyes; fireworks; ceramics;
glass; well drilling; USEPA drinking water guideline is 2 mg/l.
Appendix 2: Representative Values for selected parameters in Sutherland Shire
Stormwater
Ammonia BOD Cu
10th
0.01
1 0.002
Median
0.04
2 0.007
90th
0.33
11 0.024
Pb
0.001
0.004
0.018
Zn
Entero Faecal Grease Total N Total P TSS
0.010
38
200
1
0.30
0.018
2
0.042
500
3700
3
0.80
0.063
9
0.161 9500 20900
9
2.27
0.220
71
These values are based on 10th, median and 90th percentile data from all Council
stormwater monitoring data. It is assumed that this will provide an idea as to the range
of expected values in stormwater, with the exception of the most extreme outliers.
Note also that data recorded as less than the method detection limit have been
assigned a value of half the detection limit. This is a standard procedure for water
quality data.