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‘Forever chemicals’ from farm sewage sludge can enter food chain
Farm sewage sludge is contaminating soils, water and potentially the food chain with “forever chemicals”, and EA sources say preventative systems in place are inadequate
Experts say chemical manufacturers have long known how persistent PFAS are and need to act, while a campaigner urges Secretary of State to “stop dragging his heels”
Investigative journalism group, Watershed, in conjunction with the Guardian, has tested treated sewage sludge (biosolids) destined for UK farmland and found levels of ‘forever chemicals’ (PFAS - per- and polyfluoroalkyl substances) that would “not be considered safe on allotments”.
Conventional wastewater treatment facilities are not equipped to filter out PFAS, allowing the chemicals to accumulate in the solid waste, which is introduced into soil when used as fertiliser.
Dr Shubhi Sharma, Scientific Research Assistant at CHEM Trust, described sewage sludge as “a major source of PFAS pollution”. She said: “There is a high chance that they are absorbed by the crops, which then can end up in our food. Cows can also become contaminated with PFAS by this route and we can end up with PFAS-contaminated milk.
“More and more studies are linking our exposure [to PFAS] to health problems such as cancer and reduced fertility. The only way to prevent PFAS pollution is to stop it at the source.”
Dr Alistair Boxall, Professor in Environmental Science at the University of York, said people should take the issue “very seriously”.
He said: “Sludge is full of nutrients, but we need to develop ways to exploit this resource while protecting the health of the environment and consumers.
“We know that exposure to PFAS may lead to a variety of health problems including liver damage, cancers, impacts on the immune system and effects on development. It is therefore a bit crazy to knowingly add these substances to the soil where we grow our food or farm livestock.
“Ultimately, it is the responsibility of the companies that have produced these chemicals. Manufacturers have known for some time how persistent PFAS are, and the potential health effects, yet they have continued to manufacture and sell them.”
In terms of enforcement action, Dr Boxall called for safe limits to be set for PFAS in sludges and soils and the introduction of monitoring programmes to ensure that these are adhered to.
“My big fear is that we could be faced with swathes of agricultural land that is so contaminated that it is unusable.”
He added: “My big fear is that we could be faced with swathes of agricultural land that is so contaminated that it is unusable.”
Georgia Elliott-Smith, an Environmental Engineer and campaigner at Fighting Dirty said that the government has been aware of the risks from sewage sludge since 2017, when its own assessors reported that English crops were contaminated.
Elliott-Smith called for a solution proposed by the Environment Agency (EA) in 2020 – to remove the ‘exempted’ status of sewage sludge and bring it into the Environmental Permitting Regime used for other industrial waste.
“We are asking, in the face of mounting evidence on the harms of forever chemicals, that the Secretary of State stops dragging his heels and gets on with the job.”
An EA spokesperson said it was working with Defra to “assess the regulatory framework in this area”, adding that effective regulation in the safety of spreading sludge on land is “vital”.
This comes as a recent EA report identified more than 10,000 “high-risk” sites contaminated with PFAS, including the Fire Service College in the Cotswolds, Heathrow Airport and RAF bases nationwide.
