Friends of the Earth today released information sourced from a Right to Information (RTI) request to the Tasmanian water authority, TasWater.
The information sought pertained to PFAS testing data from TasWater and was received by Friends of the Earth in December 2023.
The information presented by TasWater was thorough and mainly dealt with PFAS detections at 29 TasWater Sewerage Plants across Tasmania. PFAS was detected in almost all samples.
This raises the question, will sometime in the future, will a buyer of biosolids from TasWater, or water authorities elsewhere in Australia, take legal action over contamination of farmland where biosolids been used?
"What procedures are currently in place to notify landowners about the PFAS content of the biosolids that they are using? Given that biosolids have been sold for decades, the issue of PFAS accumulation on farmland should not be discounted." Land Use Researcher for Friends of the Earth Anthony Amis asked.
The worst performing sewerage treatment plant according the RTI data was Cambridge Sewerage Treatment Plant located in close proximity to Hobart Airport.
The main findings from the RTI information were:
Approximately 88.5% of all test regimes for sludge/biosolids were positive for at least one PFAS chemical and approximately 55% of test regimes in effluent/influent being positive for at least one PFAS chemical
Almost 2000 individual biosolid/sludge samples tested positive for PFAS.
Only four tests were conducted in a drinking water supply (Hobart) and all were negative.
45% of targeted Trade Waste tests detected PFAS chemicals, sometimes at very high levels.
PFOS was the main PFAS chemical of concern, with by far the highest amounts detected at the Cambridge Sewerage Treatment Plant, located near Hobart Airport. 88% of PFAS detections at Cambridge STP were for PFOS.
76% of all the tested treatment plants would the breach lower end of the proposed National Environment Management Plan (NEMP) guidelines for PFHxS+PFOS for biosolids/sludge. 7% would breach lower end of the NEMP for PFOA.
Cambridge Sewerage Treatment Plant, Ranelagh and St Helens would have exceeded the higher proposed NEMP Guideline of PFHxS + PFOS levels higher than 31μg/kg. Both Cambridge and Blackmans Bay breached the lower end of the scale for PFOA.
The highest PFAS average detections were recorded at Brighton Sewerage Treatment Plant (but from a limited sample size), for Perfluroalkyl Sulfonamides chemicals MeFOSAA, EtFOSAA and MeFOSE.
In April 2020, PFOS was detected at 2,500 times over the 99% ANZECC trigger at Selfs Point Sewerage Treatment Plant, but it is unclear if this testing was conducted in influent, effluent or within the plant itself. Between 2021-2023 however the PFOS averages dropped significantly at Selfs Point to an average of 0.0135μg/L 1.5 times over the ANZECC 99% trigger level.
In 2023 PFHxS in effluent samples at Cambridge STP averaged 0.02125μg/L and the PFOS detections averaged 0.174μg/L, 19 times over the ANZECC 99% trigger level for PFOS.
TasWater information regarding STP influent coming into treatment plants was very limited.
Findings can be found here: https://www.foe.org.au/taswater
