Huge volumes of sewage sludge have been used to fertilise Scottish farmland. Studies show it contains microplastics, forever chemicals and cancer-linked pollutants.
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Far right actors have used gaming to recruit youngsters for some time but experts say they are increasingly using codes and imagery to avoid moderation.
More than half a million tonnes of sewage sludge spread on Scotland's fields
Huge volumes of sewage sludge have been used to fertilise Scottish farmland. Studies show it contains microplastics, forever chemicals and cancer-linked pollutants.
Some 643,000 tonnes of sewage sludge has been spread on Scotland’s fields amidst mounting evidence that it contains a cocktail of toxic chemicals, The Ferret can reveal.
Data we obtained from the Scottish Environment Protection Agency (Sepa) via freedom of information details the extent that the substance has been applied in rural areas across the country between 2020 and 2024.
Sewage sludge is the byproduct of domestic and industrial sewage and wastewater, which is treated by Scottish Water and waste and water management firms, during which some contaminants are removed.
The mud-like residue is then given or sold to farmers as a low cost, nutrient-rich fertiliser to spread on agricultural land to help the growth of grass, grains and crops for humans and animals.
But recent studies, including from Scotland’s James Hutton Institute and Scottish Environment LINK, have highlighted several pollutants even in supposedly refined sewage sludge, which were not removed by treatment. They include microplastics, forever chemicals and pharmaceuticals.
Once spread, these contaminants enter soil and leach into water, potentially affecting wildlife, livestock, crops, and, in-turn, human health. Applying untreated sludge to Scottish was finally banned as part of new legislation brought in last year.
One MSP said the scale of sewage sludge spreading uncovered by The Ferret was “staggering” and implored the Scottish Government to review it “as a matter of urgency”.
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Environmental charities urged ministers to introduce a temporary ban on treated sludge spreading until more information about the risks comes to light.
Sepa said it works with others to monitor emerging contaminants and reduce any potential environmental impacts, adding that it inspects areas where sludge has been spread, and analyses soil samples.
We found that between 2020 and 2024, nearly a fifth of all the sludge spread in Scotland – 111,789 tonnes – was in Perth and Kinross. It was followed by Aberdeenshire (97,950 tonnes), the Scottish Borders (87,000 tonnes), and East Lothian (68,500 tonnes).
Large amounts were also spread in Midlothian, Highland, Fife, and Dumfries and Galloway.
More than a third of all sewage sludge, which is rich in nitrogen, was spread in areas at risk from agricultural nitrate pollution.
According to the Scottish Government, large quantities of nitrogen can harm the environment and humans by leaching into groundwater, and running off into waterways.
Sepa’s data also shows that sewage sludge is authorised to be stored at 2,528 locations across Scotland, although the regulator said the number of active sites at any one time can be low.
Microplastics, forever chemicals and pharmaceuticals
Sewage sludge has been found to include man-made organic compounds such as PFAS “forever chemicals”, and PCBs, which could possibly cause cancer in humans. It can also contain pharmaceuticals and personal care products, which are disposed of down drains and toilets.
The continued release of pharmaceuticals into the environment has been linked to certain bacteria and viruses becoming immune to medicine.
Degraded soil can release the vast amounts of carbon it stores into the atmosphere, create flood risks by leaching water, and lose fertility, thereby putting food production at risk.
According to research from Cardiff university, UK land has among Europe’s highest concentrations of microplastics due to sewage sludge spreading.
Scotland’s Hutton institute said “significant quantities” of microplastics were entering agricultural soils through repeated sewage sludge application, adding that many of the pollutants it detected can harm soil health.
It called for better regulation and monitoring, stricter regulations to limit the pollution of wastewater, improved wastewater treatment to remove contaminants, and limits on sludge spreading until more research is done.
A recent study from the institute and Aberdeen’s Robert Gordon University found that microplastic levels rose by 1,450 per cent after four years of sludge-spreading in North Lanarkshire, and remained elevated 22 years later.
A 2012 study from Aberdeen scientists into sheep grazed on sludge-treated pastures found that chemicals had impacted the health and fertility of the animals and their offspring.
Dairy farmers using chemicals akin to those found in sewage sludge have reported similar issues in cattle including high abortion rates and decreasing milk yields. One farmer in the north of England reportedly lost an entire herd.
Officials reportedly discovered high levels of PFAS in water, crops, cattle, soil – and in farmers – from Maine farms where sludge had been spread. PFAS contamination on some of the state’s farms reportedly put farmers out of business.
In 2023, we reported how environmental charities accused the Scottish Government of failing to act on the recommendations from a review it did in 2016. Many of these were eventually adopted in new legislation passed last year, which tightened the rules around spreading.
But environmentalists warn that the new laws do nothing to regulate contaminants found in sewage sludge, including PFAS, pharmaceuticals or microplastics.
Green charities Fidra and the Environmental Rights Centre for Scotland (ERCS) have both called for a moratorium on sludge spreading while the risks and alternatives are investigated.
“More must be done to protect human and environmental health from potential risks associated with the complex mixture of contaminants found in sewage sludge”, said a Fidra spokesperson.
“Fidra asks that the regulation of sewage sludge contaminants in Scotland – currently only certain metals and pathogens – be strengthened to address microplastics, PFAS, pharmaceuticals/anti-microbial agents and other substances of concern”.
ERCS claimed that communities had expressed concerns about the risks associated with sewage sludge spreading “for over two decades” and argued that new Scottish regulations introduced last year “don't go far enough”, calling for a moratorium on agricultural use of sewage sludge.
“We need to adopt the precautionary principle and reevaluate the risks of sewage sludge, including investigating the potential harm of unregulated known and emerging contaminants,” said Dr Shivali Fifield, chief officer of the legal centre.
Scottish Greens environment spokesperson, Mark Ruskell MSP, said the scale of spreading uncovered by The Ferret was “staggering” and “raises obvious questions about what we are allowing into our food system and environment, and the lack of regulations or scrutiny”.
He added: “We urgently need tighter monitoring, full transparency about where sewage sludge is being spread, and updated regulations to remove ‘forever chemicals’ from products and supply chains.
“The Scottish Government must review this practice as a matter of urgency and put public safety and environmental protection before convenience and profit.”
The Scottish Government said the spreading of sewage sludge was “a long-established practice and an effective way of recovering value and avoiding waste”.
“We currently have no plans to introduce a ban or moratorium on this practice,” a spokesperson clarified.
“Scotland has very high standards of environmental quality and levels of Per-or polyfluoroalkyl substances (PFAS), also known as forever chemicals, detected in the environment are generally very low.
“However, this is an area where the Scottish Government is working with the other governments of the UK, as well as both Sepa and Scottish Water to understand the PFAS risk and that appropriate, recommended mitigations are in place.”
Scottish Water, which processes sewage sludge, said it works with Sepa to “mitigate identified risks” in sewage sludge “wherever possible”.
“The water industry is investigating contaminants in sludges and we are actively involved in this research and want to understand the quality of sludge that we produce and the impact that it could have on the environment,” said a spokesperson.
“Additionally, as part of planning for the future, we are investigating a range of different treatment technologies to understand if they can eliminate or reduce contaminant levels in bioresources.”
Sepa said it works with partners “to assess and strengthen the evidence base on emerging contaminants, as well as working to reduce any potential environmental impacts”.
Amendments to environmental legislation, made last year, “strengthened soil protection values and monitoring requirements and prohibited the use of untreated sewage sludge on land for the first time,” a spokesperson added.
“Sepa requires operators to hold the appropriate authorisation and meet legally binding conditions, including requirements for testing and record-keeping. Our role is to regulate and enforce this legislation.”
Farming union NFU Scotland argued that sludge can provide a valuable source of recycled nutrients, “helping to support soil health and reduce reliance on manufactured fertilisers”.
David Michie, senior policy manager for crops said he recognised concerns around emerging contaminants found in wastewater, which he stressed was a complex issue that extends beyond agriculture.
Regulations on the use of sewage sludge must keep up with emerging evidence, he said. “As responsible stewards of the land, farmers take soil health and environmental protection extremely seriously and will continue to comply with all current regulations and guidance,” Michie added.
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Jamie is an investigative journalist who writes on issues such as illicit finance, dark money, political influence, land ownership, nature, the environment and far right extremism. He loves puns but has yet to use them in his reporting.
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