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Quantifying risks to Australian drinking water quality

By Anthony Amis – FoE Pesticide and Drinking Water Campaigner

Since December 2017, I have been building up a national database of breaches to the Australian Drinking Water Guidelines (ADWG), which are published by the National Health and Medical Research Council (NHMRC). The breaches are slowly being added to The Australian Drinking Water Map, online at

The prime motivation for establishing this map was to better understand which communities around Australia are facing the biggest problems in regards to drinking water quality. Another reason was to better understand what chemicals are currently being tested for by the various state and local government agencies responsible for drinking water quality across Australia. Also of concern was what levels of particular substances are found at what levels and where.

As of May 2018, information for all states and territories across Australia (except NSW and the ACT) has been uploaded. The most comprehensive data relates to South Australia 2000-16. Almost all of the data included on the map are breaches to the ADWG. The information is patchy with a lot more information ready to be uploaded. But already clear patterns are emerging, with the database highlighting over 900 health-related breaches to ADWG, recorded in hundreds of different communities. The following list collates the top ten highest number of substances breaching the ADWG, mainly over the past few years.

1. E.coli: The issue of safe drinking water is dominated by the need to safely disinfect water from a variety of microorganisms and other nasties which if consumed can cause a range of sometimes fatal illnesses. Chlorine is the major method of disinfection used by Australian water treatment plants as it is cheap to use and has been used successfully for decades. Water borne illnesses such as cholera and typhoid have been largely eradicated in water supplies by the use of chlorine. Water authorities therefore must be vigilant in their quest to eliminate microorganisms from the water supply system.

According to the ADWG: "E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment." E.coli, therefore is the most frequently detected microorganism, and accounts for approximately 30% of breaches to the ADWG. One organism per 100 ml is regarded as a breach and hundreds of water supplies in cities and towns across Australia have recorded positive samples for E.coli. Once detected, water authorities must then isolate and eradicate the source of the contaminant. Boil Water Notices are usually issued if E.coli is detected, alerting community members to the dangers of E.coli in their drinking water. Tasmania has a high number of Boil Water Notices.

2. Trihalomethanes: In the quest to use chlorine as a disinfectant, problems can arise. In 1974, it was discovered that chlorine can react with organic molecules in source water and create disinfection by-products (DBPs). Further research found that some of these by-products are dangerous and potentially cancer-causing. Water authorities across Australia only test for a fraction of the 700 known DBPs, with many local governments in Queensland and NSW not testing at all.

The mostly commonly detected DBP are Trihalomethanes (composed of chloroform, bromoform, bromodichloromethane and dibromochloromethane). THMs account for approximately 23% of all breaches to the ADWGs. This figure could be higher if the NHMRC decide to lower the Australian guideline to levels similar to those in overseas countries. The THM guideline in Australia is 250 µg/L (parts per billion), whilst the equivalent standard in the United States in 80 µg/L.

Whilst Australian authorities claim that Australian waterways have higher levels of natural organic matter in source water than in other countries – meaning more potential reactions with chlorine ‒ there is little doubt that if the guideline in Australia was lowered, hundreds more communities in Australia (perhaps 50% of the population) would be consuming water regarded as being unsafe because of THMs.

It is also noteworthy that 28% of the US population have a gene that causes DNA changes when they are exposed to chlorine in drinking water and swimming pools. A similar population cohort could be assumed to exist in Australia.

3. Lead: Almost 7% of breaches to the ADWG are caused by this heavy metal. Interestingly, most detections of lead are from pipelines and brass fittings in households. Lead was banned as a solder in water pipes and water tanks in Australia in 1989, however older plumbing can still leach lead. Lead is also found in currently used brass plumbing fittings, where it is added to make the brass more "pliable and workable".

Lead is a dangerous heavy metal that can damage nervous connections and cause blood and brain disorders. Lead has been linked to impaired cognitive development in children and a number of other health problems. In some communities, lead is entering the water supply via pollution upstream ‒ this is the case with Rosebery in Tasmania. Lead has been a problem throughout Australia, with problems in Tasmania receiving media attention in recent years.

4. Chloroacetic Acids: Over 6% of breaches relate to Chloroacetic Acids, which again are disinfection by-products, created by a reaction with chlorine and naturally occurring humic and fulvic acids. Haloacetic Acids (HAAs) have been linked to a number of illnesses including skin irritations, some cancers and birth defects. The formation of HAAs has been linked to natural organic materials in source water, chlorine dose, chlorination pH, temperature, contact time, and bromide ion concentration. HAAs detected in Australia are mainly Trichloroacetic Acid and Dichloroacetic Acid, with most detections occurring in Victorian rural water supplies. HAAs are rarely tested for in many areas of Australia, so breaches to the ADWGs are likely to much higher than what has been reported.

5. Chlorine: Approximately 3% of breaches are for excessive levels of Chlorine. Chlorine disassociates in water and can create Free Chlorine. Chlorine and hypochlorites are toxic to microorganisms, hence their widespread use as a disinfectant. Chlorine can cause health problems if it is detected in water above 5mg/L (as Total Chlorine). Sometimes errors or breakdowns at water treatment plants can occur. Errors at plants can include: wrong inputs leading to calculation errors, failure to follow operating standards, instrument errors and dosing systems can malfunction.

6. Aluminium: No health guideline has been set for Aluminium under the ADWGs. 2.8% of all breaches >0.5 mg/L have occurred mainly in Victoria and Tasmania. Aluminium can be found in natural waterways, but is also used at water treatments plants as a coagulant (e.g. Aluminium Sulphate or Alum). Aluminium is a neurotoxin and can pass through the gut barrier and enter the bloodstream. Aluminium has also been linked to Alzheimer Disease.

7. Fluoride: 2.3% of breaches are for Fluoride. Fluoride is the most controversial "additive" to water supplies and communities are still fighting to stop water authorities adding fluoride. The current "safe" guideline for Fluoride is 1.5 mg/L and this level is rarely exceeded in drinking water supplies where Fluoride is added. The highest levels recorded in Australia, 20 times over the guideline, occurred in the Brisbane suburbs of Brendale and Warner in 2009, caused by equipment malfunction at the local water treatment plant. However, many communities in regional areas of Australia are reliant on groundwater for their drinking water. In areas where Fluoride occurs naturally due to geological factors, levels can far exceed the "safe" guideline. Some communities in outback Queensland for instance have recorded Fluoride levels four times higher than the safe guideline.

8. Manganese: 1.8% of breaches to the ADWGs relate to Manganese. Manganese is a natural element and is often found in soil and minerals in combination with iron. The greatest exposure to Manganese comes from food. Studies from Canada have found that high levels of Manganese in drinking water can impact on children's IQs and can impact on the nervous system.

9. Arsenic: 1.55% of breaches related to Arsenic. Arsenic is bio-accumulative and health problems may not eventuate until 10-15 years after exposure. Arsenic can enter a water supply through geology and also dust and leaching. It is highly toxic and long-term exposure can cause cancer and skin lesions. Cardiovascular problems and diabetes have also been linked to arsenic as well as cognitive difficulties in children.

10. Nitrate: 1.4% of breaches. According to the ADWGs: "Nitrate is the product of oxygenated nitrogen created from the breakdown of organic matter; lightning strikes; inorganic pesticides; or explosives." Nitrate levels between 50‒100 mg are regarded as being a potential health problem for children under the age of three months. Methemoglobinemia (blue-baby syndrome) is caused by the blood not being able to deliver enough oxygen to the body. High levels of Nitrate have been recorded in drinking water, mainly in central Western Australia and central Northern Territory.

Published in Chain Reaction #133, September 2018. National magazine of Friends of the Earth Australia.

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