Menindee fish deaths follow up: Darling-Barka River water tests
The NSW Environment Protection Authority (EPA) is testing water samples from the Darling-Barka River in response to the major fish deaths at Menindee in mid-March 2023. This testing forms part of the EPA’s investigation into the cause of the fish deaths.
Test results for water and fish samples, with links to laboratory reports are listed below.
Printed copies of test results are distributed through outlets in Menindee (Police Station, Post Office, Medical Centre, cafes and the local supermarket).
Summary reports
The NSW Environment Protection Authority (EPA) collected three water samples on 24 April 2023 at Menindee along the Darling-Barka River.
Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, bacteria, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorous levels are high. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae and algal toxins
Algae, including blue-green algae, and the algal toxin Cylindrospermopsin was detected in all three samples collected from the Darling-Barka River at Menindee.
An ‘amber alert’ is in place in the Darling-Barka River at Menindee as of 10 May 2023.
Information about algae alerts is available at https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
All metals in the Darling-Barka River samples were under the levels set to protect water life.
Bacterial
The concentrations of the bacterial indicator, enterococci, are below guideline values for recreational use (NHMRC 2008).
Sample locations
Water was sampled on 24 April 2023 from three locations on the Darling-Barka River at Menindee.
- Sample 1 – approximately 840m NE of Menindee Golf Club
- Sample 2 – end of Maiden St
- Sample 3 – beneath Menindee St bridge

More sampling
The EPA is conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.
In-field measurements
At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
All parameters are within the expected ranges.
Sample name | Location | Temp (°C) | Dissolved oxygen (mg/L) | Electrical conductivity (µS/cm) | pH | Turbidity (NTU) |
---|---|---|---|---|---|---|
1 |
approximately 840m NE of Menindee Golf Club |
19.0 |
8.0 |
504 |
8.2 |
158 |
2 |
End of Maiden St |
19.0 |
6.6 |
506 |
8.1 |
154 |
3 |
Beneath Menindee St bridge |
19.0 |
5.9 |
510 |
8.0 |
167 |
Nitrogen, phosphorus and ammonia
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at three times higher than the guideline value while total phosphorous was detected at four times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all samples for a range of algal species, including blue-green algae. The algal toxin Cylindrospermopsin was detected in all samples.
The algae levels detected fall within the ‘amber’ alert levels. An ‘amber alert’ is in place in the Darling Barka River at Menindee as of 10 May 2023.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all three locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water | NHMRC (2008)2 | Sample (total acid-extractable metals) | ||
---|---|---|---|---|
Recreational Water Guidelines | Sample 1 | Sample 2 | Sample 3 | |
(mg/L) | (mg/L) | (mg/L) | (mg/L) | |
Aluminium |
No value |
2.7 |
2.6 |
3.8 |
Arsenic |
0.07 |
0.003 |
0.003 |
0.003 |
Chromium |
0.5 |
0.003 |
0.003 |
0.004 |
Cobalt |
No value |
0.0016 |
0.0017 |
0.0020 |
Copper |
20 |
0.0029 |
0.0029 |
0.0033 |
Lead |
0.1 |
0.0010 |
0.0013 |
0.0014 |
Nickel |
0.2 |
0.0048 |
0.0049 |
0.0055 |
Zinc |
30 |
0.005 |
0.005 |
0.006 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water | ANZG 20183 | Sample (dissolved metals) | ||
---|---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) | Sample 1 | Sample 2 | Sample 3 | |
(mg/L) | (mg/L) | (mg/L) | (mg/L) | |
Aluminium |
0.055 |
<0.04 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.002 |
0.002 |
0.002 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0003 |
0.0002 |
0.0002 |
Copper |
0.0014 |
0.0014 |
0.0013 |
0.0010 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0031 |
0.0031 |
0.0028 |
Selenium |
0.005 |
<0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
References
ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines
Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia
NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council
NSW Department of Primary Industries (DPI) Fisheries collected 5 samples of golden perch (Macquaria ambigua) from the Darling-Barka River at Pooncarie on 28 March.
The gastrointestinal tract and gills of the fish were analysed for metals and pesticides. The gastrointestinal tract can show what chemicals have been ingested by the fish and the gills give an indication of overall exposure from the surrounding water.
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment.
The only metals found in the gastrointestinal tract of the fish were zinc and mercury. These metals are known to bioaccumulate in fish. No gastrointestinal tract data are available as background in NSW, but these concentrations are below concentrations reported internationally.
Zinc and mercury were also found in the gills of the fish. This indicates some recent exposure to these metals from the water. However, water concentrations were all below water quality guidelines indicating these metals will not have adversely impacted the health of the fish.
Heavy Metal | Reported mean concentration (mg/kg) in international literature for gastrointestinal tract | Reported mean concentration (mg/kg) in international literature for gills | Concentration in the gastrointestinal tract (mg/kg) | Concentration in gills (mg/kg) |
---|---|---|---|---|
Mercury |
0.02-3.6 (12 fish species with varying food regimes)1 |
0.007 - 0.03 (perch)2 |
0.044-0.055 |
0.023-0.036 |
Zinc |
11-559 (pike and bream)3 |
12-171 (pike and bream)3 |
10-15 |
21-28 |
1Regine 2006 2 Luczynska 2016 3 Rajkowska 2013
Download the full test reports: 28 March
The full report (with individual's names and addresses redacted for privacy) are available for download
Sample locations
Fish samples were collected from two locations near Pooncarie on 28 March 2023.
- Sample 1 – Downstream of Pooncarie Weir
- Sample 2 – Pooncarie Cafe
References
FSANZ. 2001. Generally expected levels (GELs) for Metal Contaminants - Additional guidelines to maximum levels in Standard 1.4..1 - Contaminants and Natural Toxicants. Australian New Zealand Food Standards Code.
1Regine M.B., Gilles D., Yannick D. and Alain B. (2006). Mercury distribution in fish organs and food regimes: Significant relationships from twelve species collected in French Guiana (Amazonian basin). Science of the Total Environment. 368: 262-270
2Luczynska J., Luczynski M. J. and Paszczyk B. (2016). Assessment of mercury in muscles, liver and gills of marine and freshwater fish. Journal of Elementology. 21(1): 113-129
3Rajkowska M. and Protasowicki M. (2013). Distribution of metals (Fe, Mn, Zn, Cu) in fish tissues in two lakes of different trophy in Northwestern Poland. Environmental Monitoring and Assessment. 185(4): 3493-3502
WaterNSW collected six water samples for the EPA on 11 April 2023 downstream of Menindee on the Darling-Barka River, the Murray River and the Great Darling Anabranch.
Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, bacteria, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorous levels are high. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae and algal toxins
Algae, including blue-green algae, were detected in all six samples. A ‘red alert’ is in place in the Murray River at Fort Courage and in the Great Darling Anabranch at Silver City Highway as of 28 April 2023. The algal toxin Cylindrospermopsin was detected in samples collected from the Murray River in these locations.
An ‘amber alert’ is in place in the Murray River at Merbein and in the Darling-Barka River at Merbein, Ellerslie and Burtundy.
Information about algae alerts is available at https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
Copper remains slightly above the level set to protect water life but well below the level harmful to fish. All other metals were under the levels set to protect water life.
Bacterial
The concentration of the bacterial indicator, enterococci, exceeded guideline values for recreational use (NHMRC 2008) at two sites in the Murray River at Fort Courage and in the Darling-Barka River at Ellerslie.
Sample locations
Water was sampled on 11 April 2023 from six locations downstream of Menindee on the Darling-Barka River, the Murray River and the Great Darling Anabranch:
- Sample 1 – Murray River at Merbein Pump Station
- Sample 2 – Darling-Barka River at Tapio
- Sample 3 – Darling-Barka River at Ellerslie
- Sample 4 – Darling-Barka River at Burtundy
- Sample 5 – Great Darling Anabranch at Silver City Highway
- Sample 6 – Murray River at Fort Courage
More sampling
The EPA is conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.
In-field measurements
At the time of sampling, WaterNSW collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
Dissolved oxygen ranged from 5.6mg/L to 10.3mg/L at the six locations. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods.
pH was outside the guideline value in the Murray River at Merbein Pump Station and Fort Courage, and in the Great Darling Anabranch at Silver City Highway.
All other parameters are within the expected ranges.
Sample name | Location | Temp (°C) | Dissolved oxygen (mg/L) | Electrical conductivity (µS/cm) | pH | Turbidity (NTU) |
---|---|---|---|---|---|---|
1 |
Murray River at Merbein Pump Station |
19.0 |
9.1 |
292 |
8.2 |
14 |
2 |
Darling-Barka River at Tapio |
19.1 |
6.0 |
449 |
7.9 |
148 |
3 |
Darling-Barka River at Ellerslie |
19.2 |
5.7 |
458 |
7.9 |
183 |
4 |
Darling-Barka River at Burtundy |
19.3 |
5.6 |
468 |
7.8 |
163 |
5 |
Great Darling Anabranch at Silver City Highway |
18.7 |
10.3 |
489 |
8.9 |
61 |
6 |
Murray River at Fort Courage |
18.7 |
8.8 |
433 |
8.3 |
69 |
Nitrogen, phosphorus and ammonia
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at five times higher than the guideline value while total phosphorous was detected at ten times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 11 April show high levels of nitrite and nitrate, and there is a potential for further harm to aquatic organisms.
Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity and as a stressor (i.e. nutrient). The levels would not be expected to be harmful to fish or promote growth in algae and aquatic plants.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all samples for a range of algal species, including blue-green algae. The algal toxin Cylindrospermopsin was detected in the samples collected from the Murray River at Fort Courage and the Great Darling Anabranch at Silver City Highway.
The algae levels detected fall within the ‘amber’ to ‘red’ alert levels. A ‘red alert’ is in place in the Murray River at Fort Courage and in the Great Darling Anabranch at Silver City Highway as of 28 April 2023. An ‘amber alert’ is in place in the Murray River at Merbein and in the Darling Barka River at Merbein, Ellerslie and Burtundy.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all six locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water | NHMRC (2008)2 | Sample (total acid-extractable metals) | |||||
---|---|---|---|---|---|---|---|
Recreational Water Guidelines | Sample 1 | Sample 2 | Sample 3 | Sample 4 | Sample 5 | Sample 6 | |
(mg/L) | (mg/L) | (mg/L) | (mg/L) | (mg/L) | (mg/L) | (mg/L) | |
Aluminium |
No value |
0.29 |
4.7 |
4.9 |
4.3 |
1.7 |
2.2 |
Arsenic |
0.07 |
0.001 |
0.005 |
0.005 |
0.005 |
0.006 |
0.005 |
Chromium |
0.5 |
<0.001 |
0.005 |
0.005 |
0.004 |
0.002 |
0.002 |
Cobalt |
No value |
0.0005 |
0.0020 |
0.0024 |
0.0021 |
0.0019 |
0.0020 |
Copper |
20 |
0.0011 |
0.0060 |
0.0055 |
0.0051 |
0.0033 |
0.0032 |
Lead |
0.1 |
0.0004 |
0.0017 |
0.0021 |
0.0018 |
0.0010 |
0.0011 |
Nickel |
0.2 |
0.0010 |
0.0068 |
0.0070 |
0.0067 |
0.0043 |
0.0042 |
Zinc |
30 |
0.001 |
0.011 |
0.010 |
0.009 |
0.005 |
0.005 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water
|
ANZG 20183 | Sample (dissolved metals) | |||||
---|---|---|---|---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) |
Sample 1 |
Sample 2 |
Sample 3 |
Sample 4 |
Sample 5 |
Sample 6 |
|
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
<0.001 |
0.005 |
0.004 |
0.004 |
0.006 |
0.004 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
<0.0001 |
0.0002 |
0.0002 |
0.0002 |
0.0007 |
0.0005 |
Copper |
0.0014 |
0.0006 |
0.0022 | 0.0019 | 0.0018 |
0.0014 |
0.0012 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
0.003 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0007 |
0.0032 |
0.0033 |
0.0031 |
0.0024 |
0.0022 |
Selenium |
0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
0.002 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
References
ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines.
Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia.
NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council.
Download the full test results: 11 April
- Report for metals and pesticides – 11 April, downstream of Menindee (PDF 2MB)
- Report for algal toxins – 11 April, downstream of Menindee (PDF 223KB)
- Report for algal identification and cell count – 11 April, downstream of Menindee (PDF 1.7MB)
- Report for nutrients – 11 April, downstream of Menindee (PDF 950KB)
The EPA collected two water samples on 4 April 2023 downstream of Menindee at Pooncarie.
Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, bacteria, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorus remain at high levels. The water samples were taken after many fish had died so the high levels could be due to rotting fish. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae and algal toxins
Algae, including blue-green algae, were detected in both samples. An ‘amber alert’ remains in place for the Darling-Barka River at Menindee and Pooncarie as of 24 April 2023. A low concentration of the algal toxin Cylindrospermopsin was detected in the sample collected from Karoola Reach.
Information about algae alerts is available at https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
Copper was slightly above the level set to protect water life but well below the level harmful to fish. All other metals were under the levels set to protect water life.
Bacterial
The concentrations of bacterial indicators, faecal coliforms and enterococci, are below guideline values for recreational use (NHMRC 2008).
Sample locations
Water was sampled on 4 April from two locations on the Darling-Barka River at Pooncarie:
- Sample 1 – Karoola Reach, approximately 60 kilometres north of Pooncarie
- Sample 2 – Pooncarie Bilbarka Park

More sampling
WaterNSW has collected more water samples for the EPA from the Darling-Barka River on 11 April 2023. The test results for these samples will also be published on the EPA webpage.
In-field measurements
At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
Dissolved oxygen at Site 1 was 2.53mg/L and at Site 2 was 3.11mg/L. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods.
All other parameters were within the expected ranges.
Sample name |
Location |
Temp (°C) |
Dissolved oxygen (mg/L) |
Electrical conductivity (µS/cm) |
pH |
Turbidity (NTU) |
---|---|---|---|---|---|---|
1 |
Karoola Reach, approximately 60km upstream from Pooncarie |
20.6 |
3.11 |
419 |
7.72 |
109.5 |
2 |
Pooncarie Bilbarka Park |
21.1 |
2.53 |
404 |
7.59 |
115.9 |
Nitrogen and phosphorus
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at five times higher than the guideline value while total phosphorous was detected at seven times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 4 April show high levels of nitrite and nitrate, and there is a potential for further harm to aquatic organisms.
Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and aquatic plants. The ammonia is likely to be from river sources including rotting fish and flood detritus rather than diffuse inputs from surrounding land.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in both samples for a range of algal species, including blue-green algae, and common toxins produced by blue-green algae. A low concentration of the algal toxin Cylindrospermopsin was detected in the sample collected from Karoola Reach.
The algae levels detected fall within the ‘green’ to ‘amber’ alert levels. An amber alert remains in place at Menindee and Pooncarie as of 24 April 2023.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples at both locations. Both samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water |
NHMRC (2008)2 |
Sample (total acid-extractable metals) |
|
---|---|---|---|
Recreational Water Guidelines |
Sample 1 |
Sample 2 |
|
(mg/L) |
(mg/L) |
(mg/L) |
|
Aluminium |
No value |
5.7 |
5.3 |
Arsenic |
0.07 |
0.006 |
0.006 |
Chromium |
0.5 |
0.008 |
0.007 |
Cobalt |
No value |
0.0031 |
0.0026 |
Copper |
20 |
0.0063 |
0.0060 |
Lead |
0.1 |
0.0024 |
0.0022 |
Nickel |
0.2 |
0.0085 |
0.0079 |
Zinc |
30 |
0.012 |
0.012 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water |
ANZG 20183 |
Sample (dissolved metals) |
|
---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) |
Sample 1 |
Sample 2 |
|
(mg/L) |
(mg/L) |
(mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.005 |
0.005 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0003 |
0.0002 |
Copper |
0.0014 |
0.0018 |
0.0018 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0031 |
0.0030 |
Selenium |
0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
Download the full test reports: 4 April
The full reports (with individual's names and addresses redacted for privacy) are available for download:
WaterNSW collected five water samples for the EPA on 3 April 2023.
Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorous levels remain high. The water samples were taken after many fish had died so the high levels could be due to rotting fish. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae and algal toxins
Algae, including blue-green algae, were detected in all five samples. An ‘amber alert’ remains in place for the Darling-Barka River at Menindee and Pooncarie as of 24 April 2023. No algal toxins were detected.
Information about algae alerts is available at https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
Copper remains slightly above the level set to protect water life but well below the level harmful to fish. All other metals were under the levels set to protect water life.
Sample locations
Water was sampled on 3 April 2023 from five locations on the Darling-Barka River between Main Weir and Weir 32:
- Sample 1 – Downstream of the main weir at Menindee
- Sample 2 – Menindee Water Treatment Plant
- Sample 3 – Upstream of Menindee Creek
- Sample 4 – Downstream of Menindee Creek
- Sample 5 – Upstream of Weir 32 at Menindee

More sampling
The EPA and WaterNSW have collected more water samples from the Darling-Barka River downstream in the Pooncarie area on 11 April 2023. The test results from these samples will also be published on the EPA webpage.
In-field measurements
At the time of sampling, WaterNSW collected in-field measurements for pH, dissolved oxygen, conductivity and temperature.
Dissolved oxygen ranged from 1.82mg/L to 7.04mg/L at the five locations. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods. One of the five sample locations detected dissolved oxygen levels below 2 mg/L.
All other parameters are within the expected ranges.
Sample name |
Location |
Temp (°C) |
Dissolved oxygen (mg/L) |
Electrical conductivity (µS/cm) |
pH |
---|---|---|---|---|---|
1 |
Downstream Main Weir |
19.4 |
7.04 |
515 |
7.72 |
2 |
Water treatment plant |
20.5 |
2.79 |
508 |
7.63 |
3 |
Upstream Menindee Creek |
20.5 |
1.82 |
506 |
7.62 |
4 |
Downstream several kms of Menindee Creek |
19.1 |
6.68 |
439.3 |
8.08 |
5
|
Upstream of Weir 32 |
19.4 |
6.39 |
437.6 |
8.04 |
Nitrogen, phosphorus and ammonia
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at four times higher than the guideline value while total phosphorous was detected at seven times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 3 April show high levels of nitrite and nitrate, and there is a potential for further harm to aquatic organisms.
Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and aquatic plants. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all samples for a range of algal species, including blue-green algae.
The algae levels detected fall within the ‘green’ to ‘amber’ alert levels. An amber alert remains in place at Menindee and Pooncarie as of 24 April 2023. No algal toxins were detected.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all five locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water |
NHMRC (2008)2 |
Sample (total acid-extractable metals) |
||||
---|---|---|---|---|---|---|
Recreational Water Guidelines (mg/L) |
Sample 1 |
Sample 2 |
Sample 3 |
Sample 4 |
Sample 5 |
|
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
||
Aluminium |
No value |
2.2 |
3.5 |
3.3 |
4.7 |
4.7 |
Arsenic |
0.07 |
0.003 |
0.003 |
0.003 |
0.005 |
0.005 |
Chromium |
0.5 |
0.002 |
0.004 |
0.004 |
0.005 |
0.005 |
Cobalt |
No value |
0.0016 |
0.0021 |
0.0020 |
0.0019 |
0.0019 |
Copper |
20 |
0.0028 |
0.0037 |
0.0035 |
0.0051 |
0.0052 |
Lead |
0.1 |
0.0010 |
0.0017 |
0.0015 |
0.0016 |
0.0016 |
Nickel |
0.2 |
0.0051 |
0.0063 |
0.0060 |
0.0063 |
0.0062 |
Zinc |
30 |
0.005 |
0.007 |
0.007 |
0.009 |
0.009 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water |
ANZG 20183 |
Sample (dissolved metals) |
||||
---|---|---|---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) (mg/L) |
Sample 1 (mg/L) |
Sample 2 (mg/L) |
Sample 3 (mg/L) |
Sample 4 (mg/L) |
Sample 5 (mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.003 |
0.003 |
0.003 |
0.003 |
0.003 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0002 |
0.0002 |
0.0002 |
0.0002 |
0.0002 |
Copper |
0.0014 |
0.0012 |
0.0011 |
0.0010 |
0.0019 |
0.0020 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0032 |
0.0034 |
0.0034 |
0.0026 |
0.0026 |
Selenium |
0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
Download the full test reports: 3 April
The full reports (with individual's names and addresses redacted for privacy) are available for download:
The EPA collected two water samples on 30 March downstream of Menindee at Pooncarie and approximately 60 kilometres upstream of Pooncarie.
Samples were checked for pesticides, excess nitrogen and phosphorus, metals, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorus remain at high levels. The water samples were taken after many fish had died so the high levels could be due to rotting fish. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae
Algae, including blue-green algae, were detected in both samples. An ‘amber alert’ remains in place for the Darling River at Menindee and Pooncarie as of 20 April 2023.
Information about algae alerts is available here https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
Copper remains slightly above the level set to protect water life but well below the level lethal to fish. All other metals were under the levels set to protect water life.
Sample locations
Water was sampled on 30 March from two locations on the Darling River downriver of Menindee:
- Sample 1 – Approximately 60 kilometres upstream of Pooncarie. This site is identified as DRKR on the full sample results.
- Sample 2 – Old Wharf Pooncarie. This site is identified at DRPW on the full sample results.
More sampling
The EPA and WaterNSW have collected more water samples from the Darling River in the Menindee area and downstream in the Pooncarie area on 3, 4 and 11 April. The test results from these samples will also be published on the EPA webpage.
In-field measurements
At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
Dissolved oxygen ranged from 2.75 mg/L to 3.56mg/L at the two locations. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods.
All other parameters are within the expected ranges.
Sample name |
Location |
Temp (°C) |
Dissolved oxygen (mg/L) |
Conductivity (µS/cm) |
pH |
Turbidity (NTU) |
---|---|---|---|---|---|---|
1 |
Approximately 60km upstream of Pooncarie (Karoola Reach) |
21.9 |
3.56 |
417 |
7.73 |
148 |
2 |
Old Wharf Pooncarie |
22.2 |
2.75 |
420 |
7.65 |
114 |
Nitrogen, phosphorus and ammonia
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at six times higher than the guideline value while total phosphorous was detected at nine times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 30 March show high levels of nitrite and nitrate, and there is a potential for further harm to aquatic organisms.
Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood detritus rather than diffuse inputs from surrounding land.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all samples for a range of algal species, including blue-green algae, and common toxins produced by blue-green algae.
The algae levels detected fall within the ‘green’ to ‘amber’ alert levels. An amber alert remains in place at Menindee and Pooncarie as of 20 April 2023.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from both locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water |
NHMRC (2008)2 |
Sample (total acid-extractable metals) |
|
---|---|---|---|
Recreational Water Guidelines (mg/L) |
Sample 1 |
Sample 2 |
|
Aluminium |
No value |
3.4 |
3.3 |
Arsenic |
0.07 |
0.005 |
0.006 |
Chromium |
0.5 |
0.004 |
0.004 |
Cobalt |
No value |
0.0018 |
0.0019 |
Copper |
20 |
0.0048 |
0.0049 |
Lead |
0.1 |
0.0016 |
0.0015 |
Nickel |
0.2 |
0.0061 |
0.0065 |
Zinc |
30 |
0.008 |
0.008 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10x drinking water guideline value, Table 9.3)
Metal in Water |
ANZG 20183 |
Sample (dissolved metals) |
|
---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) (mg/L) |
Sample 1 (mg/L) |
Sample 2 (mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.005 |
0.006 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0002 |
0.0002 |
Copper |
0.0014 |
0.0019 |
0.0018 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0029 |
0.0031 |
Selenium |
0.011 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
Download the full test reports: 30 March
The full reports (with individual's names and addresses redacted for privacy) are available for download:
WaterNSW collected five water samples for the NSW Environment Protection Authority (EPA) on 30 March.
Samples were checked for pesticides, excess nitrogen and phosphorus, metals, algae and algal toxins.
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorus remain at high levels. The water samples were taken after many fish had died so the high levels could be due to rotting fish. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae
Algae, including blue-green algae, were detected in five samples. An ‘amber alert’ remains in place for the Darling River at Menindee and Pooncarie as of 20 April 2023.
Information about algae alerts is available here https://www.waternsw.com.au/water-services/water-quality/algae-alerts
Metals
Copper remains slightly above the level set to protect water life but well below the level lethal to fish. All other metals were under the levels set to protect water life.
Sample locations
Water was sampled on 30 March from five locations on the Darling River between Main Weir and Weir 32:
- Sample 2– Downstream of the main weir at Menindee.
- Sample 3 – Menindee Water Treatment Plant
- Sample 4 – Upstream of Menindee Creek
- Sample 6 – Several kilometres downstream of Menindee Creek
- Sample 7 – Downstream of Weir 32
In-field measurements
At the time of sampling, WaterNSW collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
Dissolved oxygen ranged from 0.73mg/L to 5.85mg/L at the five locations. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods. Two of the five sample locations detected dissolved oxygen levels below 2 mg/L.
All other parameters are within the expected ranges.
Sample name |
Location |
Temp (°C) |
Dissolved oxygen (mg/L) |
Electrical conductivity (µS/cm) |
pH |
Turbidity (NTU) |
---|---|---|---|---|---|---|
2 |
Downstream Main Weir |
21.5 |
5.85 |
515 |
7.69 |
50 |
3 |
Water treatment plant |
22.3 |
1.4 |
519 |
7.44 |
55 |
4 |
Upstream Menindee Creek |
22.2 |
0.73 |
499 |
7.46 |
68.1 |
6 |
Downstream several kms of Menindee Creek |
21.5 |
5.01 |
443.6 |
7.78 |
97 |
7
|
Downstream of Weir 32 |
21.7 |
4.78 |
443.1 |
7.69 |
101.4 |
Nitrogen, phosphorus and ammonia
Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at five times higher than the guideline value while total phosphorous was detected at seven times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 30 March show high levels of nitrite and nitrate, and there is a potential for further harm to aquatic organisms.
Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and aquatic plants. The ammonia is likely to be from river sources including rotting fish and flood detritus rather than diffuse inputs from surrounding land.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all samples for a range of algal species, including blue-green algae, and common toxins produced by blue-green algae.
The algae levels detected fall within the ‘green’ to ‘amber’ alert levels. An amber alert remains in place at Menindee and Pooncarie as of 20 April 2023.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all five locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water |
NHMRC (2008)2 |
Sample (total acid-extractable metals) |
||||
---|---|---|---|---|---|---|
Recreational Water Guidelines (mg/L) |
Sample 2 |
Sample 3 |
Sample 4 |
Sample 6 |
Sample 7 |
|
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
(mg/L) |
||
Aluminium |
No value |
2 |
2.2 |
2.7 |
3.9 |
4.1 |
Arsenic |
0.07 |
0.003 |
0.003 |
0.004 |
0.005 |
0.005 |
Chromium |
0.5 |
0.003 |
0.003 |
0.003 |
0.005 |
0.005 |
Cobalt |
No value |
0.0019 |
0.0020 |
0.0018 |
0.0019 |
0.0019 |
Copper |
20 |
0.0031 |
0.0030 |
0.0033 |
0.0049 |
0.0050 |
Lead |
0.1 |
0.0012 |
0.0014 |
0.0015 |
0.0016 |
0.0018 |
Nickel |
0.2 |
0.0054 |
0.0055 |
0.0059 |
0.0062 |
0.0065 |
Zinc |
30 |
0.005 |
0.005 |
0.007 |
0.008 |
0.009 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water |
ANZG 20183 |
Sample (dissolved metals) |
||||
---|---|---|---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) (mg/L) |
Sample 2 (mg/L) |
Sample 3 (mg/L) |
Sample 4 (mg/L) |
Sample 6 (mg/L) |
Sample 7 (mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.003 |
0.003 |
0.003 |
0.005 |
0.005 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0002 |
0.0003 |
0.0002 |
0.0002 |
0.0002 |
Copper |
0.0014 |
0.0011 |
0.0007 |
0.0009 |
0.0018 |
0.0018 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0031 |
0.0032 |
0.0035 |
0.0028 |
0.0029 |
Selenium |
0.011 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
Download the full test reports: 30 March
The full reports (with individual's names and addresses redacted for privacy) are available for download:
Summary
Pesticides
Samples were scanned for more than 600 pesticides. None were detected.
Nitrogen and phosphorus
Nitrogen and phosphorus were at high levels. The water samples were taken after many fish had died so the high levels could be due to rotting fish. If nitrogen and phosphorus stay high they can cause algal blooms.
Algae
Algae, including blue-green algae, were detected in all six samples. An ‘amber alert’ is now in place for this part of the river. This means:
- people should not drink untreated river water.
Metals
Levels of metals were within the limits set for recreational use – that is, swimming and canoeing are OK. Copper was above the level set to protect water life but well below the level harmful to fish. All other metals were under the levels set to protect water life.
Sample locations
Water was sampled on 21 March from six locations on the Darling River between the outlet at Main Weir and Weir 32:
- Sample 1 – Outlet to Lake Pamamaroo
- Sample 2 – Downstream Main Weir
- Sample 3 – Darling River at the Menindee Rail Bridge
- Sample 4 – Darling River upstream of Menindee Creek
- Sample 5 – Darling River several kilometres downstream from Menindee outlet.
- Sample 6 – Weir 32
In-field measurements
At the time of sampling, WaterNSW collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.
Dissolved oxygen ranged from 0.41mg/L to 5.97mg/L at the six locations. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods. Three of the six sample locations detected dissolved oxygen levels below 3 mg/L.
One sample taken from the Darling River, upstream of Menindee Creek detected dissolved oxygen levels below 1mg/L. Dissolved oxygen lower than 1 mg/L can be lethal for animals that can’t move to oxygen-rich areas.
All other parameters are within the expected range.
Sample name |
Location |
Temp (°C) |
Dissolved oxygen (mg/L) |
Conductivity compensated (SPC – µS/cm) |
pH |
Turbidity (NTU) |
---|---|---|---|---|---|---|
1 |
Outlet to Lake Pamamaroo |
22.6 |
5.97 |
478 |
7.8 |
109 |
2 |
DS Main Weir |
23.0 |
1.83 |
529 |
7.5 |
73.3 |
3 |
Darling River at the Menindee rail bridge/town water offtake |
24.5 |
1.21 |
671 |
7.6 |
61.0 |
4 |
Darling River u/s of Menindee Creek |
24.4 |
0.41 |
478 |
7.5 |
45.4 |
5 |
Darling River several km downstream of Menindee outlet |
22.6 |
4.84 |
420 |
7.9 |
120 |
6 |
Weir 32 |
22.9 |
4.18 |
421 |
7.8 |
123 |
Nitrogen and phosphorus
Sample results show that Total Nitrogen and Total Phosphorous are higher than the trigger values given for lowland river ecosystems in NSW (ANZG 2018). Total nitrogen was detected at eight times higher than the guideline value while total phosphorous was detected at eleven times higher. Algal blooms are possible if these nutrients remain elevated.
Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The water samples from 21 March show high levels of ammonia, nitrite and nitrate, and there is a potential for harm to aquatic organisms.
Algae and algal toxins
A wide variety of algae was tested for. There were positive detections in all six samples for a range of algae species, including blue-green algae.
WaterNSW has advised that the algae levels detected fall within the ‘green’ to ‘amber’ alert levels. An amber alert is currently in place.
Pesticides
As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all six locations. All samples came back negative for pesticide detection.
Metals
Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.
Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per NHMRC and ANZECC guidelines, respectively.
Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).
Metal in Water |
NHMRC (2008)2 |
Sample (total acid-extractable metals) |
|||||
---|---|---|---|---|---|---|---|
Recreational Water Guidelines (mg/L) |
Water1 (mg/L) |
Water2 (mg/L) |
Water3 (mg/L) |
Water4 (mg/L) |
Water5 (mg/L) |
Water6 (mg/L) |
|
Aluminium |
No value |
4.1 |
0.88 |
2.1 |
0.73 |
1.9 |
1.4 |
Arsenic |
0.07 |
0.005 |
0.004 |
0.005 |
0.004 |
0.006 |
0.005 |
Chromium |
0.5 |
0.005 |
<0.001 |
0.002 |
<0.001 |
0.002 |
0.002 |
Cobalt |
No value |
0.0023 |
0.0006 |
0.0011 |
0.0008 |
0.0006 |
0.0005 |
Copper |
20 |
0.0050 |
0.0026 |
0.0033 |
0.0017 |
0.0041 |
0.0091 |
Lead |
0.1 |
0.0018 |
0.0004 |
0.0009 |
0.0004 |
0.0005 |
0.0004 |
Nickel |
0.2 |
0.0071 |
0.0042 |
0.0054 |
0.0044 |
0.0040 |
0.0037 |
Zinc |
30 |
0.009 |
0.002 |
0.004 |
0.002 |
0.003 |
0.003 |
2NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)
Metal in Water |
ANZG 20183 |
Sample (dissolved metals) |
|||||
---|---|---|---|---|---|---|---|
Water Quality Guideline for aquatic ecosystems (95% species protection) (mg/L) |
Water1 (mg/L) |
Water2 (mg/L) |
Water3 (mg/L) |
Water4 (mg/L) |
Water5 (mg/L) |
Water6 (mg/L) |
|
Aluminium |
0.055 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
<0.04 |
Arsenic |
0.013 |
0.004 |
0.004 |
0.005 |
0.004 |
0.006 |
0.005 |
Cadmium |
0.0002 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Chromium |
0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
Cobalt |
No value |
0.0003 |
0.0003 |
0.0003 |
0.0006 |
0.0002 |
0.0001 |
Copper |
0.0014 |
0.0025 |
0.0018 |
0.0019 |
0.0018 |
0.0016 |
0.0016 |
Lead |
0.0034 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Manganese |
1.9 |
<0.001 |
<0.001 |
0.008 |
0.073 |
<0.001 |
<0.001 |
Nickel |
0.011 |
0.0037 |
0.0034 |
0.0037 |
0.0036 |
0.0028 |
0.0029 |
Selenium |
0.011 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
<0.005 |
Silver |
0.0005 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
Zinc |
0.008 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
<0.001 |
3ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
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