Using sewage sludge as fertiliser could be polluting farmland and food with “forever chemicals” and microplastics, a group of charities says.
A report by eco coalition Scottish Environment LINK has demanded stronger regulations.
Farmers use the sludge, a by-product of wastewater treatment, as a low-cost, natural fertiliser for soil.
It said it was better than using environmentally-damaging chemical fertilisers but stressed tighter rules are necessary to monitor contaminants.
Sewage sludge contains vital nutrients and organic matter which can help soil stay healthy and crops grow.
But the charities’ body warned it is also often contaminated with pathogens, chemicals and tiny particles of plastic, in turn polluting the soil.
And it said this pollution is not covered by existing regulations meaning the practice of spreading sewage sludge risks the “accumulation of pollutants in Scottish farmland, crops and food sources”.
Dr Joanna Cloy,senior project manager at ScotLINK member organisation Fidra, said: “This is a complex issue which affects a wide variety of stakeholders across industries, with sewage sludge being variously categorised as a waste material, fertiliser or energy generating resource.
“Sewage sludge acts as a sink for persistent contaminants removed from wastewater. With the Scottish Government pledging to deliver a more environmentally sustainable farming sector that protects its soils, the agricultural use of sewage sludge in its currently contaminated form should be avoided.
“This report provides a key set of recommendations which seek to address the complexity and provide solutions for better regulating this practice as well as future innovations for developing contaminant-free sludge.”
The report is calling for monitoring of key chemical contaminants in soils and sludge.
It also said maximum permitted levels should be introduced for damaging microplastics and other “emerging contaminants”.
Oceans have been polluted with microplastics at a staggering rate, in recent years with 24 trillion pieces accumulated.
