Drinking water quality
What the results tell us for Tumut
Tumut Shire has six water supply systems. The quality of drinking water from these systems was of a high overall standard during the reporting period. The 2004 national guidelines for microbiological quality—that no indicator bacteria (Escherichia coli and thermotolerant coliforms) be found in any water sample—were met in 99% of the samples from across the shire. In those instances where such bacteria were recorded, the appropriate response protocol was adopted to address the problem.
The drinking water quality requirements for chemical parameters, under the 2004 national guidelines, were met in 100% of samples across the shire except for aluminium, iron, pH and turbidity. The relevant national guideline values for aluminium, iron, pH and turbidity were exceeded in 19%, 4%, 35% and 7% of samples, respectively. None of the exceedences was considered to represent a health risk (although the number of samples was sometimes small).
This State of the Environment report includes one more water supply system (Morgans Reserve) than the 2000 State of the Environment Report. It is not possible to compare directly water quality during the current reporting period with that in the previous period due to differences in the type of data used for each State of the Environment report. However, both the Adelong and Talbingo water supply systems appear to have shown an improvement in their quality performance for microbiological contamination.
Quality of the water supply systems
Six water supply systems provided drinking water to 10,020 people living in the Tumut, Adelong, Batlow, Talbingo, Brungle and Morgans Reserve townships within Tumut Shire. Two microbiological and at least 24 chemical parameters (see Interpreting the data) were monitored in the shire's drinking water as part of NSW Health's drinking water monitoring program (NSW Health 2000). The shire's drinking water was not monitored for pesticides as, under current protocols (NSW Health 2000), the shire was not considered to be at risk.
The majority of microbiological and chemical water quality parameters monitored from January 2001 to June 2004 met the relevant 2004 national guidelines. Those parameters that did not are shown in Table 1.
Responses to all instances of bacterial contamination were successful, so there was no need for the Water Utility or Public Health Unit to recommend boiling water before using for human consumption. The reported exceedences of chemical parameters in the six water supply systems were not considered to be of concern (see Interpreting the data).
Water from the Adelong supply system was of uniformly high quality during the reporting period. All microbiological water quality parameters monitored met the relevant 2004 national guidelines. Of the 25 chemical water quality parameters monitored, only one (pH) exceeded the 2004 guidelines. A slightly increased pH level was recorded in October 2001 and March 2003. The pH exceedences were marginal and not considered to be a health hazard.
The Adelong supply system appears to have improved its microbiological performance, as some instances of contamination were reported in the last reporting period compared with none during the current period.
Water supplied by the Batlow supply system was of a high standard during the reporting period. The system recorded one instance of E. coli contamination in March 2001; the appropriate response protocol (see NSW Health 2000) was adopted to solve the problem and subsequent water samples were free of such bacteria. Water from the system met the guideline requirements for all chemical parameters except for pH on two occasions (July 2002 and September 2003); these exceptions did not cause any health concern.
The Brungle water supply was of good quality during the reporting period. Water from the Brungle supply system registered three exceedences of E. coli (April 2002, and February and April 2003). Subsequent water samples did not show continued presence of such bacteria, indicating that the response protocol adopted had addressed the problem.
Water from this supply system recorded a small number of exceptions for four chemical parameters: aluminium, iron, pH and turbidity. Two aluminium exceedences occurred in March and September 2003, one instance of iron exceedence in September 2003 and one pH exceedence in April 2004. Four turbidity exceedences occurred in October 2001, July 2002, and March and September 2003. These isolated exceedences were marginal and not considered to be a health concern.
Morgans Reserve system
The Morgans Reserve supply system provided water of a very high standard consistently throughout the reporting period. All microbiological water quality parameters monitored met the relevant 2004 national guidelines. The chemical quality of the water also met guidelines standards except for one occurrence of a slightly increased pH (in March 2004). No data on pH levels were available for the rest of the reporting period.
The Talbingo supply system did not register any exceedence of the 2004 national guidelines for microbiological or chemical parameters, indicating that the quality of the water supplied by this system was of superior standard consistently throughout the reporting period.
The Talbingo supply system appears to have improved its microbiological performance, as some instances of contamination were reported in the last reporting period compared with none during the current period.
Water from the Tumut supply system was of a high quality for the reporting period. All microbiological water quality parameters monitored met the relevant 2004 national guidelines. Exceedences of the 2004 guidelines were recorded for two of the 25 chemical water quality parameters. A slightly elevated level of aluminium was recorded on three occasions (June, September and November 2003). Thirteen instances of a slightly elevated pH were recorded (during August and November 2002; March, April and September 2003; and March, April and May 2004). None of these exceedences was considered to be a health concern.
About the data
Water samples were collected by Tumut Shire Council and sent to relevant NSW Health laboratories for chemical and microbiological analyses, based on a schedule outlined in NSW Health (2000). Details of the monitoring program, including allocation of sample numbers based on the type of water supply system and population, and details of the response protocol when national standards are exceeded, can also be found in NSW Health (2000).
NSW Health provides analytical service through its Division of Analytical Laboratories in Sydney (microbiology and chemistry) and the Greater Murray Public Health Laboratory in Wagga Wagga (microbiology only). The results are owned by Tumut Shire Council but maintained on the NSW Drinking Water Database (a statewide internet-based database) by NSW Health's Water Unit.
The data used for this report were sourced from the NSW Drinking Water Database. Results used only cover the period 1 January 2001 to 30 June 2004, as the database does not hold earlier data for any local government area. Further details of the database can be obtained from the NSW Health Water Unit.
Interpreting the data
The Australian Drinking Water Guidelines 2004 (NHMRC and NRMMC 2004)—here called the 2004 national guidelines—provide the standards for drinking water quality nationally. Although the 2004 national guidelines have superseded the 1996 national guidelines, they are yet to be ratified by the NSW Government. Consequently, the 1996 national guidelines are still being used in the NSW Drinking Water Database for determining exceedences. However, for this State of the Environment report, the 2004 national guidelines were adopted as the standards for analyses and interpretation of data to assess drinking water quality in the shire during the current reporting period.
E. coli and other thermotolerant coliforms are used as specific indicators of faecal contamination and hence the safety of water for drinking. When these organisms are detected in water samples, the water utility responds by raising the level of treatment with chlorine or other acceptable disinfectants to destroy potentially pathogenic coliforms.
The NSW Drinking Water Database contains instances of samples not meeting guideline requirements for total coliforms. This is because the database still uses the 1996 national guidelines which set a guideline value of 0 CFU/100 mL for total coliforms. However, since the 2004 national guidelines does not adopt a guideline value for coliforms (excluding E. coli) due to the lack of direct health significance, such exceptions in the data have been ignored for purposes of this report.
Reported exceedences of chemical parameters in the shire were not considered to be of health concern as they were only marginally outside the 2004 national guideline values and/or the values are not health based:
- aluminium (recorded values of 0.23–0.27 mg/L compared with guideline value of 0.2 mg/L; guideline not health based)
- iron (one reported value of 0.52 mg/L compared with guideline value of 0.3 mg/L)
- pH (maximum reported level of 9.2 compared with guideline range of 6.5–8.5; all reported exceedence values were well within the 6–10.8 range reported for major Australian reticulated water supplies).
It was not feasible to make direct comparisons of water quality between results for this reporting period and the previous one. This is because the 2000 State of the Environment Report used aggregated data to report on three water quality issues (bacteriological tests, chemical tests and tests for pesticides), while the current report is based on a suite of individual chemical and microbiological parameters.
Management Strategy, National Health and Medical Research Council and the Natural Resource Management Ministerial Council.
NSW Health (2000) Drinking Water Monitoring Program, October 2000, NSW Health Department, viewed 30 April 2005, http://www.health.nsw.gov.au/public-health/ehb/water/monitoring/DWMonitProgOct00.pdf.
|Water quality parameter3||January–June 2001||2001–02||2002–03||2003–04||January 2001–June 2004|
|No. of samples||No. of failures||Success rate (%)||No. of samples||No. of failures||Success rate (%)||No. of samples||No. of failures||Success rate (%)||No. of samples||No. of failures||Success rate (%)||Total no. of samples||Total no. of failures||Overall success rate (%)|
|Adelong Water Supply System (supplies Adelong; supply population 930)|
|Batlow Water Supply System (supplies Batlow; supply population 1700)|
|Brungle Water Supply System (supplies Brungle; supply population 90)|
|Morgan's Reserve Water Supply System (supplies Morgan's Reserve; supply population 500)|
|Talbingo Water Supply System (supplies Talbingo; supply population 300)|
|All water samples tested during the reporting period met ADWG (2004) requirements|
|Tumut Water Supply System (supplies Tumut; supply population 6,500)|
1 For an explanation of the 2004 national guidelines, see Interpreting the data; 2 No results available prior to 1 January 2001; 3 Does not include total coliforms