Traces of 'forever chemicals' detected at filtration plants, Sydney Water confirms

A small amount of cancer-linked chemicals have been found in Sydney's water catchments but remain well below acceptable levels for safe drinking water, Sydney Water has confirmed.

The perfluoroalkyl and polyfluoroalkyl substances (PFAS) were found in low levels at key filtration plants including Warragamba, Prospect Reservoir and Orchard Hills after water testing conducted in June.

They were found in slightly higher levels at the Cascade Dam in the Blue Mountains and North Richmond.

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What are PFAS chemicals?

PFAS chemicals are dubbed as "forever chemicals" because they never break down.

The PFAS chemicals found were perfluorooctane sulphonate (PFOS), perfluorohexane sulphonate (PFHxS), and perfluorooctanoic acid (PFOA).

PFAS chemicals are a group of synthetic chemicals used in industrial appliances as they can resist heat, stains, grease and water, according to Sydney Water.

They are also used in upholstery, paper coating, cosmetics and sunscreen.

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Is Sydney tap water safe to drink?

The chemicals were all found in doses lower than the recommended Australian safe drinking water guidelines, so the water is still deemed safe to drink.

The guidelines are currently being reviewed by the National Health and Medical Research Council.

While Australia deems the amount of chemicals found as safe, the water does not meet the US safe drinking water guidelines.

The limit for PFOS and PFHxS is a combined total of 0.07 micrograms per litre (µg/L) or 70 parts per trillion (ppt).

For PFOA, the limit is less than 0.56 µg/L.

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NSW Health Director of Health Protection Dr Jeremy McAnulty said Sydneysiders should be "reassured" that the drinking water is safe to drink.

"We certainly encourage people to drink tap water...I can say drinking Sydney water is safe," he said.

"The results are below the levels of concern in the Australian drinking water guidelines."

He also said that the lower guidelines in the US could be related to the country's laboratories' ability to detect minute amounts of chemicals in the water, rather than lower levels of PFAS being detected as dangerous.

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Where were PFAS chemicals found?

PFAS Chemicals were found in high levels at the Cascade water filtration plant in Katoomba.

They were found in low levels at the North Richmond, Prospect, Warragamba and Orchid Hills filtration plants.

They were not found in the Woronora, Macarthur, Napean or Illawarra filtration plants.

Do PFAS chemicals cause cancer?

Forever chemicals could potentially be linked to cancer in large doses and specific contexts, however, most of the prior studies into PFAS chemicals require further study to establish clear links, according to the US National Cancer Insitute.

Australian studies have shown links between PFAS contamination and ill health in other species, including platypus, according to the Sydney Morning Herald.

In animal species, it has been linked to liver damage and damage to immune systems, low birth weight, birth defects, delayed development and newborn deaths.