Concern over build-up of hazardous materials on land spread with sewage sludge
Concern over build up of potentially hazardous metals on land
Two separate research studies are examining the environmental impact of spreading sewage sludge on farmland.
The Environmental Protection Agency (EPA) recently published the results of research which provides data and evidence on the sources and scale of microplastic pollution in Irish freshwaters.
Urban wastewater treatment plants were identified as one of the largest point sources of microplastics which are plastic particles less than 5mm in diameter. They are formed either through the breakdown of large plastic particles or through intentional production for products such as cosmetics and cleaning agents.
The research was led Anne Maire McMahon in the Marine and Freshwater Research Centre at Galway Mayo Institute of Technology (GMIT).
She said that landspreading of these sludges on agricultural land poses risks to terrestrial ecosystems and potentially further risks to freshwater systems.
At present, land spreading of sewage sludge is recommended 20 m from lakes and river channels and 10 m from small water courses and domestic wells.
According to the authors of the research, further investigation is required to determine pathways of microplastics entrained in sewage sludge.
When this knowledge has been gained, they recommend an assessment of the ability of the current rules around the use of Biosolids in agriculture which prevent microplastics from entering freshwater systems should be carried out.