The results were concerning. PFAS was present in several parts of the city’s drinking water catchment, mostly within Australian drinking water guidelines, but Medlow Dam, near the township of Medlow Bath, showed the presence of “forever chemicals” above safe guidelines.
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On August 7, the dam and neighbouring Greaves Creek Dam were shut off from the drinking water supply by closing the pipeline that links them to Middle Cascade Dam near Katoomba, though this information was not made public until August 28.
In early September, the Herald commissioned independent tests that showed far higher levels of potentially carcinogenic chemicals in waterways around Medlow Dam.
Above the dam, in Adams Creek, PFAS was present at concentrations of 3.7 micrograms per litre – far higher than the 0.09 micrograms per litre reported in government samples, and over 50 times higher than Australian drinking water guidelines.
“If you’re not testing, you’re not going to find anything,” said Western Sydney University water scientist Ian Wright, who took samples for the independent tests. “What we’re seeing is that once you start sampling, there are these hotspots that start to crop up.”
NSW Health said all local water utilities should screen for PFAS, and the government would assist with test kits and arrange for accredited testing if required. Town water was required to be within healthy guidelines, it said.
The per- and polyfluorinated alkyl chemicals, which are prized for their stain-repellent and water-resistant properties and delivered US corporate giant 3M billions of dollars in profits over decades, have been used in hundreds of consumer products and never break down in the environment.
Water NSW is continuing to test water and soil samples around Medlow Dam to identify the source of the contamination. One line of inquiry is focussing on the use of firefighting foam containing PFAS being used to douse burning vehicle crash sites on the Great Western Highway in the past.
Sydney Water said on Friday drinking water guidelines were not relevant when analysing water samples from the catchment before it had passed through a filtration plant.
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“Samples taken from creeks and waterways which have not been treated for human consumption should not be taken into account when considering the safety of that water for drinking,” the agency said in a statement. “All water provided for human consumption in NSW continues to meet Australian safety standards.”
Water entering the drinking supply from the network of dams around the Blue Mountains shows the presence of PFAS at elevated levels, but within Australian guidelines.
Drinking water samples from Katoomba and Blackheath have shown PFAS levels of around 0.025 to 0.03 micrograms per litre since testing started in June – by far the highest levels in the catchment area but within Australian guidelines of 0.07 micrograms per litre.
Dramatic turnaround as state backs widespread water testing for forever chemicals”
