Is rainfall a source of PFAS chemicals in Sydney drinking water reservoirs?
Friends of the Earth Australia
Early this week Friends of the Earth received two GIPA requests from WaterNSW and Sydney Water. The information FoE requested concerned detections of all PFAS chemicals through their drinking water supplies. Over the past 6 months, WaterNSW and Sydney Water have conducted hundreds of PFAS tests and have published online PFAS results pertaining only to those listed under the Australian Drinking Water Guidelines, namely PFOS, PFHxS and PFOA.
Sydney Water however screen for a total of 45 PFAS chemicals, with WaterNSW screening for 30. FoE was interested in what other PFAS chemicals were being detected. Information gathered from the GIPA requests was presented to Select Committee of PFAS contamination in Waterways and Drinking Water throughout New South Wales by FOE on February 5.
The Sydney Water GIPA request showed high Perfluorobutanoic Acid (PFBA) levels (>20ng/L) at Katoomba/Blackheath Cascade WFP in October and November and North Richmond WFP in October, November and December. However higher spikes occurred at Nepean WFP (34ng/L) in October 15 2024, Illawarra WFP (49ng/L) November 11 2024, Woronora WFP (64ng/L) on November 19 and Macarthur WFP (69ng/L and 28ng/L) on November 19 and October 22nd.
No PFBA was detected by Sydney Water at Warragamba or Prospect WFP's, counter to the two detections at these locations by WaterNSW testing. No PFBA was detected at Orchard Hills WFP. No PFBA was detected in WaterNSW testing outside of the Sydney region.
Friends of the Earth spokesperson Anthony Amis said "The PFBA spikes seem to occur during and after rainfall events with the highest occurring in forested catchments south of Sydney. High PFBA levels were also detected in Blue Mountain water supplies after rainfall events in December. PFBA and other PFAS chemicals have been found in precipitation in scientific studies in other regions of the world. It would appear that PFBA is coming down with the rain in Sydney".
At several locations PFBA dominates almost all PFAS detections (eg ~98% of all PFAS detections at Illawarra, Nepean and Illawarra Water Filtration Plants, ~83% at Macarthur) WFP.
Rainfall does not fully explain the highest levels of PFBA because high rainfall events in Sydney in late September 2024 don't appear to have caused a rise in PFBA detections, although it would appear that testing probably has to occur when the rainfall events actually occur. Testing does not occur after every significant rainfall event.
Perfluorobutanoic acid (PFBA) is a breakdown product of other PFAS chemicals. It is a short chain PFAS chemical, meaning that it should have a shorter half-life than long chain PFAS chemicals such as PFOS. High levels of PFBA have resulted in thyroid and liver effects. Water filters such as reverse osmosis and granular activated carbon will decrease exposures to PFBA. PFBA can dissolve faster than other PFAS chemicals meaning that it does not stick as well to soil. PFBA has been detected in Melbourne area and it can disperse long distances via atmospheric transport and precipitation.
More information here: https://www.foe.org.au/is_rainfall_a_source_of_pfas_chemicals_in_sydney_drinking_water_supplies
Contact details:
Anthony Amis: 0425841564
anthony.amis@foe.org.au