Water can dissolve many minerals or chemicals and transport microbiological contaminants. Testing of drinking water is common practice in Western Australia, particularly in mining settings, where semi-permanent and permanent mine camps require adequate and clean drinking water for all employees and camp users.
The Department of Health (DoH) has outlined guidance on Standard Drinking Water Tests (SDWT) which provides a base set of analyses designed to detect chemical and microbiological
contaminants that are most commonly found in Western Australia waters. This can be found here: https://ww2.health.wa.gov.au/Articles/S_T/Standard-drinking-water-test. The analysis is designed to tell you the following:
How safe your water is for drinking purposes?
The levels of contamination in your drinking water
The aesthetic quality of your drinking water.
SDWTs conducted by participating laboratories within WA comply with National Association of Testing Authorities (NATA) requirements. Results provided by these laboratories are accepted by the Department of Health.
Microbiological Tests:
The microbiological analysis will identify total coliforms (a type of bacteria) and faecal coliforms in drinking water. The total coliform test will show the total bacterial loading found in the water sample. The faecal coliform test will indicate the level of faecal contamination in the water and how safe the water is to drink.
Chemical Quality Tests:
The chemical quality test is made up of a range of chemical elements and compounds. Some of the elements are heavy metals that may pose a risk to your health while others may only affect the taste, odour and appearance of the water (aesthetic characteristics).
Additional Testing:
It is important that you identify any additional hazards that may indicate the need for additional analytical testing. A qualified environmental consultant can assist with providing technical advice. Some of the potential considerations are as follows: • intensive agriculture, industry or mining • fuel and chemical storage areas • poorly maintained septic tanks and other liquid waste disposal systems • excessive or inappropriate use of fertilisers, animal manures, pesticides, herbicides and insecticides • accidental spills of chemicals. If you find any of these activities or items in or on the catchment area you may need to consider additional testing.
Collecting a Sample:
Collection of drinking water samples should be done in a manner that limits the potential for unwanted contaminants during collection and handling of the sample to ensure an accurate representation of drinking water quality, such as sterilisation, and good handling techniques.
Sample Bottles:
Collecting a drinking water sample requires the use of a set of appropriately supplied sampling bottles from a nominated NATA accredited laboratory. These pre-rinsed and sterile bottles are used to ensure that no other contaminants have been introduced into the sample. Each of the bottles in a given set will contain various size bottles and preservatives to ensure the correct preservation and sample volume for the nominated drinking water test.
Sample Collection:
Appropriate sample collection means removing contamination potential from the sample point, to ensure an accurate representation of collected sample water. This may include heat treatment of the sample point using a propane lighter to remove microbiological build up at the sample point, and the use of disposable nitrile-free gloves to be worn by the person sampling for the duration of the collection activities. These gloves should be discarded and replaced between sample points.
Sample Storage:
Samples should be stored at required temperatures, as advised by the nominated laboratory. This usually involves storage and transportation of the samples in a cooled esky for delivery. Partic
ular analysis may also require submission of samples within designated timeframes to meet the preservation criteria of a given analysis. In some instances this can be less than 2 days. Ensuring good coordination of sampling and delivery options, particularly in remote areas is crucial in receiving accurate sample results.
Quality Assurance:
For analytical Quality Assurance (QA), a duplicate sample may be collected at one of the sampling points. Generally, a 1:20 ratio for collection of QA samples is appropriate to ensure data can be shown to be reliable and sample collection procedures appropriate. By undertaking accurate and representative sampling of drinking water, an appropriate assessment of the quality of your drinking water can be defined, and analytical results relied upon.
Useful references:
Department of Environment Regulation. 2021. Assessment and management of contaminated sites. Contaminated sites guidelines. December 2014.
Department of Health. 2011. Standard Drinking Water Test. Delivering a Healthy WA. Government of Western Australia, Department of Health, Public Health.
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