Plastic Leaching Into Farmer’s Fields at Alarming Rate: New Report
October 17, 2022 | United Nations Environment Programme
Plastics are accumulating in the world’s soils at a worrying rate, according to a new report from the United Nations Environment Programme (UNEP).
The 29th edition of UNEP’s Foresight Brief highlights how plastics used extensively in farming – from plastic coated plastic fertilizers to mulch film – are contaminating the soil and potentially threatening food security. Microplastics are also impacting human health when transferred to people through the food chain.
“There is only a finite amount of agricultural land available,” says Professor Elaine Baker from the University of Sydney, the report’s co-author. “We are starting to understand that the build-up of plastic can have wide-ranging impacts on soil health, biodiversity and productivity, all of which are vital for food security,” she says.
Plastics are ubiquitous in agriculture. Macroplastics are used as protective wraps around mulch and fodder. They cover greenhouses and shield crops from the elements. They are used in irrigation tubes, sacks and bottles — and intentionally added microplastics are even used as coatings on fertilizers, pesticides and seeds.
But over time, macroplastics slowly break down into microplastics of shards less than 5mm long – and seep into the soil. These microplastics can change the physical structure of earth and limit its capacity to hold water. That can affect plants by reducing root growth and nutrient uptake. Chemical additives in plastics that leach into the soil can also impact food value chains and lead to health implications.
According to the Foresight Brief, the single-biggest source of microplastic pollution in soil is fertilizers produced from organic matter, such as manure. Known as biosolids, these can be cheaper and better for the environment than manufactured fertilizers. But manure is mixed with microspheres, tiny synthetic particles commonly used in soap, shampoo, makeup and other personal care products, which is cause for concern.
Some countries have banned plastic microspheres, but many other microplastics continue to enter the water system. These include everything from cigarette filters to tire components to synthetic fibres from clothes. Experts say the varying size and composition of microplastics make them difficult to remove once they are in sewage.
