Snowy River
Indicator: Drinking Water Quality
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Snowy River Shire
Drinking water quality is monitored as part of the New South Wales (NSW) drinking water monitoring programme, and detailed results can be accessed through the website http://www3.health.nsw.gov.au/waterqual/samples/register.cfm.
This report on drinking water quality for 2004-2008 is prepared from examination of this data, to illustrate the quality aspects of the water supplied for domestic consumption in the Shire. The Shire uses both public and private water supplies, only those supplies recorded on the health database are available for comment in this report.
The general water quality is good, regarding both bacteria and for the inorganic constituents. The only area of concern is the occurrence of E. coli in the supply during the warmer months, particularly in the East Jindabyne and Eucumbene Cove systems. This was observed in the 2000-2004 data, and has continued through 2005-2008. Pre-emptive action by the supply authority is recommended, by increasing disinfection prior to the summer for East Jindabyne, and installing Ultra Violet disinfection for Eucumbene Cove.
Quality of the water supply systems
Data are available for Cobbin Bore, Lake Eucumbene, Lake Jindabyne, Little Thredbo River, Thredbo River and Snowy River systems. These systems supply water to about 6,000 people living in ten communities, the largest being Jindabyne. Thirty to forty parameters were measured, including Total Coliforms and E.coli. In fluoridated supplies fluorine was measured daily. Herbicides and pesticides were not measured. The coliform indicators were measured at different intervals depending on the supply. Jindabyne supply was most frequently evaluated, with more than 600 samples taken over the four-year period. Smaller supplies such as Cobbin Bore were only sampled 40 times over 2004-2008 with coliform counts on each sample, whereas inorganic constituents were only measured four times.
Adaminaby - supplied from Lake Eucumbene
This system supplies 2,800 people with reticulated water that has been disinfected with chlorine and fluoridated. Of 101 samples tested only one sample showed one organism in 100 mL water. This is water of consistently high microbial quality.
Eight samples were tested for inorganic components, apart from fluoride, which was tested 27 times. Field results for fluoride were reported 23 times, with one exceeding the guideline value at 2.2 mg/L compared to the guideline value of 1.5. This has no health significance.
Two samples showed iron above the Guideline Values, with the highest of 0.55 compared with a Guideline value of 0.3 mg/l. This has no health significance. Overall an excellent quality water supply.
Dalgety - supplied from the Snowy River
This system supplies 100 people with reticulated water, which has been disinfected with chlorine. One hundred and one samples were assessed for E. coli and 5 showed counts above zero. The highest was nine organisms per 100 mL on 4th October 2005. Two other samples showed 4 organisms per 100 mL on 27th March 2007 and 10th March 2008. It is apparent that the system is vulnerable to microbial contamination in late summer
Eight samples were assessed for inorganic components, and none showed concentrations of concern.
Eucumbene Cove - supplied from Lake Eucumbene.
This system supplies 10 people with reticulated water, which has not been treated. Eight of 79 water samples showed E.coli above zero, with the highest count being 200 organisms per 100ml. Examination of the dates of high E.coli counts showed two events, one in the second half of July 2007 and the other from the 27 Nov to 13 Dec. 2007. Both of these events are ‘real’, and not due to sampling or analytical error, since they continued over several sampling dates. In both cases the results returned to zero within three weeks. The reason for, and possible consequences of, these exceedences should be investigated as they indicate faecal contamination of the supply.
Inorganic component analysis showed two samples with high iron content in 2007, one sample with a slightly low pH value and one showed high colour. Heavy rain frequently leads to discolouration, which itself is not a public health issue. These components are not a cause for concern.
Jindabyne system -supplied from Lake Jindabyne
This system supplies 2,800 people with reticulated water, which has been disinfected with chlorine and fluoridated. Only one of 302 water samples showed E.coli above zero, with four organisms per 100mL sample. This indicates an overall good quality drinking water supply.
Inorganic components exceeding the Guideline Values were pH (3 of 46 samples, with a peak value of 8.8, compared with a guideline range of 6.5-8.5), turbidity (one sample only) and aluminium (2 of 46 samples, with a peak of 0.31 mg/L compared to a Guideline value of 0.2 mg/L)). None of these inorganic components are of concern.
Jindabyne East - supplied from Lake Jindabyne.
This system supplies 2,095 people with reticulated water which has been disinfected with chlorine and fluoridated Of 204 water samples tested for E. coli, 10 samples showed the presence of these organisms. The highest count was 16 E. coli per 100 mL of water on 5th February 2008. In the months of January and February 2008, a total of 5 samples showed the presence of E. coli in the drinking water supply.
In general low numbers of E. coli appeared in the samples during summer/autumn each year. The presence of E.coli in water samples was also in the 2000-2004 report, occurring in summer. It appears that there is an on-going issue with E. coli in this water supply during the warmer months, which should receive attention.
pH was measured in nine samples, of which four exceeded the guideline range of 6.5-8.5, and the highest was 10.2 in the summer of 2007. This alkalinity occurred each year in summer, including 2008. This alkalinity may cause skin, eye and intestinal irritation in sensitive individuals.
Fluoride content of the field samples of water showed two instances of exceeding the NHMRC Guideline value of 1.5mg/L, on 4 July 2007 and 2 September 2008, with concentrations of 1.64 and 2.2 mg/L respectively. The mean concentration was 0.8 mg/L, well below the Guideline.
Kalkite - supplied from Lake Jindabyne
This system supplies 150 people with reticulated water, which has been disinfected with chlorine and fluoridated One hundred and thirty samples were assessed for E. coli, and three showed the organisms present. The highest count was 62 per 100mL on 13th December 2006. Two individual samples with two organisms per 100ml were taken on 21st December 2005 and 24th January 2006. No organisms were detected in samples from 2008.
The inorganic components showed iron and lead above the Guideline Values in about half of the eight samples assessed. The highest iron concentration was 1.61 mg/L (mean 0.7) compared to 0.3 mg/L Guideline Value. Similarly lead reached 0.04 mg/L. (mean 0.015) compared to a Guideline value of 0.01. These persisting high concentrations of metals require attention.
Lake Crakenback Village. Supplied from the Little Thredbo River.
This system supplies 250 people with water which has been disinfected with UV light.
This private water supply was tested 77 times for E. coli and none were detected. Seven samples were assessed for inorganic components and no results exceeded the Guideline Values. An excellent water supply.
Cobbin Estate supply - Bore source
This system supplies 50 people with reticulated water which has been disinfected with UV light. This private supply from bores was assessed for E.coli 40 times in the reporting period and only one sample showed two organisms on 15th February 2006. Inorganic components were measured 4 times, lead showed a small exceedance on a single sample. A good quality water supply.
Barry Way - supplied by Lake Jindabyne
Sample point for fluoride analysis only on the Jindabyne water. Measurements on 21 samples, no values exceeded the Guideline Values.
About the data
Interpreting the data
In 2004 the National Health and Medical Research Council (NHMRC) introduced the Australian Drinking Water Guidelines, which provides the basis for quality assessment. These Guidelines have not included Total Coliforms as a measure of water quality for health purposes, as the organisms are widely present in soil and untreated water and grow in water pipes, and do not reflect the content of pathogenic organisms. Monitoring for Escherichia coli is, by contrast, particularly informative, since this organism occurs in large numbers in faeces and hence is an effective indicator of faecal contamination. It is killed by standard drinking water treatment and therefore should not occur in domestic supplies. The drinking water Guideline Value is zero organisms per 100ml sample and any detected organisms present in the water therefore exceed the guideline, and should result in an increase in the disinfection of the supply.
This remedial action should be taken until the E. coli count returns to zero.
While there are many other pathogens present in faecal contamination of water, monitoring of E. coli has been shown to be an effective and straightforward method for public health. Where the data from a water supply for this period show E .coli present, it has been commented upon for each water supply reported.
Concentrations of inorganic components of water supplies do not have such a sharp impact on health as faecal contamination. The Guideline Values reflect safe concentrations for lifetime exposure, and minor exceedences, which briefly occur, are of negligible risk to public health. Inorganic constituents become a risk to public health when they consistently exceed the Guideline Values, with the risk increasing with the concentration in the supply. Where these have occurred, they are commented upon in the appropriate section of the report. Unless there is accidental contamination of the supply, it is unlikely that any substantial variations in concentration of inorganic components will occur throughout any year.
Continuing concentrations that significantly exceed the Guideline Values require investigation and rectification.
The information assessed in this report is available on the NSW Health water database, and uses the current NHMCR Drinking Water guidelines as the reference for the analytical comparisons. The results included in this report are from 1 January 2005 to the time of writing, mid-November 2008.
References
NSW Department of Health Drinking Water Database 2008 http://www3.health.nsw.gov.au/waterqual/samples/register.cfm.
NHMRC and NRMMC 2004. Australian Drinking Water Guidelines. National Water Quality Management Strategy. http://www.nhmrc.gov.au/publications/synopses/eh19syn.htm
NHMRC and NRMMC – see National Health and Medical Research Council and Natural Resource Management Ministerial Council
