Council monitoring of Macleay River water quality continues

Kempsey Shire Council’s monitoring of the levels or arsenic and antimony has identified a slight increase in the level of antimony however arsenic levels remain within the normal background levels for the upper Macleay River. The testing was sparked by a fear of contamination of the Macleay River from an overflowing sediment control dam on the Hillgrove Mine site near Armidale. Discharge from the mine site enters Baker’s Creek and flows through into the Macleay River upstream of Georges Creek.

The results are shown in the following table together with guideline values from the National Water Quality Management Strategy for Drinking Water, Recreational Use, Irrigation and Livestock consumption. Background ranges are also shown to provide an indication of previous test results.

Macleay River water quality monitoring

Sample details			Test results (mg/l)
Sample date	Location	Sample type	Antimony	Arsenic
30/08/2011	Bellbrook	River - surface	0.005	0.003
30/08/2011	Bellbrook	Bore - raw water	0.005	0.002
1/09/2011	Bellbrook	River - surface	0.004	0.002
1/09/2011	Bellbrook	Bore - raw water	0.004	0.001
1/09/2011	Bellbrook	Treated water - Town supply	0.002	<0.001
Typical background levels at Bellbrook (from previous testing)			0.001	up to 0.007
1/09/2011	Willawarrin	River - surface	0.004	0.002
1/09/2011	Willawarrin	Treated water - Town supply	0.002	0.001
Australian Drinking Water Guideline values			0.003	0.007
Long term irrigation limit values				0.1
Short term irrigation limit values				2.0
Livestock watering trigger value				0.05

New samples were taken on Monday 5 September and the results will be available by Friday 9 September. Further sampling will continue over the next week.

The results so far show a slight increase in the levels of Antimony relative to background levels. The levels of Arsenic are within background ranges and below the requirements for all water uses. Previous testing has identified naturally occurring spikes of up to 0.013mg/l of Arsenic in the past.

Council’s Director Infrastructure Services, Robert Scott said “water treatment systems at both Bellbrook and Willawarrin have been producing drinking water that complies with the Australian Drinking Water Guidelines and is safe to drink. The test results show that the levels of Arsenic and Antimony is well within the allowable ranges for other agricultural uses.”

Any further rainfall events in the short term are likely to result in continued runoff from the mine site escaping into the river. Council will be continuing to monitor the situation as a precautionary measure until confirmation is provided that level in the overflow storage dam have been reduced and further runoff will not occur.