Sewage by-products used on farms contaminated with ‘forever chemicals’

Sydney sewage by-products contaminated with so-called “forever chemicals”, have been used to help produce food, the ABC can reveal.

For more than 30 years the waste from the city’s wastewater treatment plants, known as biosolids, have been sent to central and southern NSW for use as fertiliser to boost crops and grazing pastures for livestock.

The practice was hailed as a solution for Sydney Water, which was trying to stop sewage flowing into waterways.

But a Sydney Water document titled Human Health and Ecological Risk Assessment for PFAS in Wastewater and Biosolids — Update (HHERA) from April 2023, obtained through freedom of information by Friends of the Earth and seen by the ABC, shows some of these biosolids contain elevated levels of per- and polyfluoroalkyl substances (PFAS).

Studies have linked exposure to these chemicals with human diseases such as high cholesterol, lower birth weight in babies and an increased risk of testicular and kidney cancer.

PFAS are laboratory-made chemicals that persist in the environment, bioaccumulate and are potentially toxic.

They are in industrial products such as firefighting foam and everyday items, like cosmetics and non-stick cookware, and eventually end up in wastewater.

“For PFAS, consumption of food needs to be evaluated. Livestock can be exposed to these chemicals by direct consumption of water … direct consumption of soil … or consumption of fodder/feed that has been grown in affected soil or irrigated with affected water,” the HHERA stated.

Friends of the Earth land use researcher Anthony Amis, who has a degree in environmental policy, said it’s a national problem that would cost “billions” to fix.

“These wastewater treatment plants are a big source of PFAS that ends up in the environment,” he said.

“Are the farmers even aware that this stuff is full of ‘forever chemicals’?”

How PFAS was found in biosolids

The HHERA revealed a type of PFAS, called PFOS, was detected at all 21 wastewater treatment plants in monitoring that occurred in 2018, 2020 and 2021.

The treatment plants that were sampled reported elevated levels of this type of PFAS that would exceed thresholds for the use of biosolids being proposed in Australian guidelines, known as the National Environmental Management Plan 3.0.

Typically, when biosolids are applied to agricultural land in NSW there are certain restrictions on application rates. These are classified as ‘restricted use’ biosolids.

“Almost 40 per cent of treatment plants reported maximum concentrations for PFOS above the draft restricted use contaminant threshold,” the HHERA said.

The most contaminated biosolids were found at the Richmond, Riverstone and Quakers Hill plants in north-west Sydney.

PFOA, which is considered carcinogenic to humans, was detected at six plants in 2018, two plants in 2020 and did not show up in 2021.

There are currently no national limits on PFAS in biosolids.

The issue of PFAS contaminated biosolids has boiled over in the United States, with a group of Texan farmers now taking legal action against federal regulators alleging they became sick, livestock were killed, drinking water was polluted and meat was contaminated.

Biosolids have been banned for agricultural use in the US state of Maine due to PFAS contamination.

In a statement, a spokesperson for Sydney Water said it complied with the NSW Environment Protection Authority’s (EPA) requirements regulating the use of biosolids, and conducted “thorough treatment and risk assessments” to ensure the products are safe for agricultural land.

“Some Sydney Water facilities would exceed the proposed new thresholds currently in the draft National Environmental Management Plan,” the spokesperson said.

“Following an updated review and refinement of the risk-based criteria by EnRiskS in 2023 due to an expanded dataset, biosolids used for grazing canola and pasture are deemed safe.”

More than half of Sydney Water’s biosolids are used for agriculture — spread on about 40 farms across central and southern NSW — while a quarter is used on forestry land and the rest goes into compost products.

“If I was a farmer using these products and potentially it’s polluted my farm … and potentially my neighbours’ properties through groundwater and runoff and dust I wouldn’t be very happy,” Mr Amis said.

“They’ve got a lot to answer for, I think, the authorities.”

Health risks

The NSW EPA first tested biosolids in NSW in 2017, with PFAS detected in all biosolids samples at 20 wastewater treatment plants across Sydney and some regional areas.

It began monitoring after a biosolids review in 2016 listed PFOS and PFOA as potential contaminants of concern.

Sydney Water’s HHERA document warns the chemicals’ potential to accumulate “makes them more likely to pose a risk to human health or the environment”.

In 2023, the EPA commissioned a study into the potential health impacts called the NSW Biosolids Guideline Review.

It found consuming meat and milk from cattle that have grazed on land applied with biosolids posed a human health risk.

“I really don’t think they should allow cattle to graze on land where these biosolids have been used. I think it’s quite outrageous actually,” Mr Amis said.

In a statement, the EPA said the review has been carried out based on “very specific modelled scenarios” and “do not represent actual risk of harm”.

The scenarios examined the possible threat from consuming homegrown produce and did not look at market supply.

NSW Health was involved in the decision to approve the use of biosolids on agricultural land.

It convened a panel of experts in microbiology and infectious diseases.

The panel concluded the risk was “negligible” if the recommended treatment and use followed the EPA guidelines.

In a statement, a spokesperson for NSW Health said “the responsibility for the regulation of biosolids rests with the NSW Environment Protection Authority”.

“EPA is conducting a review of the current guidelines … and consulting with a range of stakeholders including NSW Health.”

River contamination

The EPA has recently started investigating the discovery of PFAS in the Belubula River in central western NSW.

It has been found at 16 locations along the river, with one of the highest concentrations of PFOS detected in Cowriga Creek, which joins the Belubula and is downstream of composting facility, Australian Native Landscapes (ANL).

ANL is one of the sites that stores biosolids from Sydney Water for distribution to local farms.

A spokesman for the company denied its site was a source of PFAS and said it was awaiting the results of further tests conducted in December.

High levels of PFOS were also found in Mackenzies Waterholes Creek, which is another tributary of the Belubula River, and is downstream of the Blayney landfill.

Blayney Shire Mayor Bruce Reynolds said council was working with the EPA to try and prevent more PFAS from getting into the environment.

“We’re probably not alone that pretty much every other waste facility in this state and across the country also has similar problems and potential leaching,” he said.

The third potential source identified by the EPA is Newmont Mining’s Cadia gold mine.

A spokesperson for Newmont acknowledged the EPA’s findings.

“Cadia has not used PFOS or PFAS on site for many years and will continue to work closely with the EPA to address any concerns,” the spokesperson said.

The EPA said results to date indicate the risk to livestock that graze adjacent to the impacted river and creeks is low.

It said, as a precaution, it will take soil samples for testing at select properties and will continue to monitor water quality in the region.

“All results so far have shown PFAS detections below the current recreational water guidelines,” an EPA spokesperson said.

Testing results are expected to be published in the new year.

Meanwhile, an updated National Environment Management Plan  is expected to be released in early 2025, which includes new PFAS thresholds for biosolids use.