The concerns about PFAS keep coming. Friends of the Earth has just received two GIPA requests from WaterNSW and Sydney Water. The information we 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 else was 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 researcher Anthony Amis on February 5.

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Map of Sydney area showing main Reservoirs. The highest PFAS loads over 2024 were centred on Cascade Water Filtration in the Blue Mountains and North Richmond WFP, both marked with red pins. The highest PFBA detections in 2024 occurred at Woronora, Macarthur, Nepean and Illawarra Water Filtration Plants and all in October/November.

Friends of the Earth applied under GIPA laws in January after seeing some data from the Blue Mountains pertaining to the water supplies of Katoomba and Blackheath from December. Both communities have been dealing with the daunting issue of coming to terms with drinking PFAS contaminated water possibly since the early 1990's. The information was gained by Blue Mountains PFAS Free campaigner Jon Dee. The information highlighted that the highest detection of PFAS chemicals in both water supplies in December was three detections of PFBA (perfluorobutanoic acid) when testing was conducted by Sydney Water. The highest levels were detected on December 16th, with a PFBA detection of 0.028μg/L (28ng/L) accounting for 68% of the entire PFAS total at Blackheath on that day. The follow up tests on December 23rd at Blackheath revealed no PFBA. Similarly Katoomba had a PFBA detection of 0.029μg/L (29ng/L) of the 16th of December and 0.15μg/L (15ng/L) one week later.

Graph of Cascades Katoomba Reservoir between June and December 2024 highlighting three spikes of PFBA in October, November and December. Katoomba recorded 11.2mm of rainfall on October 19 and 23mm on October 18 with a PFBA spike occurring when water was tested on October 22. However, 14.8mm was recorded on the 26th of September without a subsequent PFBA spike. 53mm fell on December 12 and 13 with a PFBA spike recorded when testing was conducted four days later.

Why wasn't there a subsequent spike of other PFAS chemicals on the dates of concern?  PFBA is known to be volatilised in the atmosphere. Could it be drifting in on clouds coming from Sydney? But PFBA is not the only PFAS chemical that can be volatised.

Graph of Cascades Blackheath Reservoir highlighting three spikes of PFBA in October, November and December.

The WaterNSW GIPA request revealed limited PFBA detections in rural NSW and detections of PFBA in two Sydney Water Filtration Plants, Warragamba and Prospect. The levels detected were higher than other PFAS chemicals, apart from a high detection of 6:2 FTS at Macarthur WFP on the 29th of October. Because there have been relatively few PFAS detections in Sydney Reservoirs, these detections would be seen to be unusual.

The Sydney Water GIPA request showed high 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, 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 by WaterNSW and none at Orchard Hills.

The 'dominance' of PFBA in the Sydney Water/Water NSW PFAS profile is highlighted in this table. At many locations PFBA dominates almost all PFAS detections. Rainfall does not fully explain the highest levels of PFBA because high rainfall events in Sydney in late September don't appear to have caused a rise in PFAS detections, although testing probably has to occur when the rainfall events actually occur.

Almost 85 per cent of Greater Sydney households, around 4.3 million people, receive their drinking water from the Prospect Water Filtration Plant, which takes in and treats water from Warragamba Dam, Upper Nepean Dam, and Prospect Reservoir. PFBA detections accounted for about one quarter of all PFAS detections at Prospect WFP. Warragamba WFP had PFAS detections of about 15% of all PFAS chemicals and Orchard Hills had no detections of PFBA. 

Woronora's catchment is forested. What is the source of the PFAS? 34mm of rain was recorded at Wollongong around this time, with 21mm falling in Sydney on the 18th of November.

Illawarra WFP is located to the west of Wollongong. About 34mm of rain occurred in Wollongong on the 18th and 19th of October.

Nepean WFP also sources water from a 'closed' forested catchment. Rainfall doesn't fully explain PFBA detections at Nepean in mid October, although 7.4mm did fall at Bargo on October 15th, the same date as the PFBA detection.

Macarthur Water Filtration Plant is another of the four reservoirs located to the south of Sydney that recorded high PFBA detections in October 22 and November 19. Perhaps the spike in November was caused by the Wollongong rainfall event?

The North Richmond WFP appears to be more influenced by whatever is flowing down the Hawkesbury River. A "Flatter" PFAS spike occurred at North Richmond WFP Reservoir for a month in October-November 2024. Very little rain was reported at Richmond in October, but 30mm fell on the 26th and 27th of September. 18mm of rain fell at Richmond on November 18 and 34mm on the 29th and 30th of November. The most rain at Richmond in December occurred on the 8th (15mm). The PFBA "spike" was detected a week later.  10 different PFAS chemicals were detected at Richmond WFP. PFBA accounted for 38% of all PFAS chemicals detected at North Richmond between June -December 2004.

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 throughout Melbourne and can disperse long distances via atmospheric transport and precipitation. Perhaps Sydney Water should embark in widespread tap water samples throughout Sydney to determine if PFAS chemicals such as PFBA are getting through filtration plants and ending up in tap water.

A graph of PFAS chemicals detected by Sydney Water in terms of most prevalent. The GIPA Request was broken into two components, this graph deals mainly with PFAS detections in reservoirs and water treatment plant inlets. 

Although PFBA was detected less than 30 times by Sydney Water, its average detection far exceeded other PFAS chemicals, indicating that when it was detected it was detected in higher amounts than other PFAS chemicals. The most toxic PFAS chemical however is PFOS, which was the second most commonly detected PFAS chemical with the third highest average detection level.

Help keep us looking at the PFAS menace. We need funds to continue data collection from around Australia. Tax deductible donations here