The increasing, intentional use of microplastics in pesticides and fertilizers has driven up their concentrations in soil to between four and 23 times the levels in marine environment, a group of U.S. environmental law experts warns.
“Deliberately added microplastics are a new, dangerous facet of the toxic triad formed by agrochemicals, plastics, and the fossil fuels used to make them,” writes the Center for International Environmental Law (CIEL) in a release announcing its report on how microplastics affect our soil, food, and future.
“In the European Economic Area (EEA) alone, 36,000 tonnes of microplastics are introduced into the environment through agrochemicals each year, accounting for more than 65% of microplastics intentionally added to the environment in that region,” CIEL writes.
“Industry production estimates suggest the problem is far wider than publicly reported,” the release adds.
Used mainly in slow- or controlled-release fertilizers (SRFs and CRFs), where a coating typically composed of a plastic polymer like polyacrylonitrile (a known toxin) helps to regulate nitrate conversion to ammonia, microplastics are also used in seed coatings and soil remediation—especially efforts to increase soil’s ability to hold water.
While they are marketed as environmentally friendly and sustainable, these substances compound the known harms of chemical-based fertilizers, as well as pesticides, by “enhancing toxicity and increasing mobility” through the food chain, the researchers say.
“With mounting evidence showing microplastics have the potential to not only cross biological barriers in the human body but also to adsorb and transport other toxic chemicals, their intentional use in agrochemicals introduces a new array of health and environmental harms,” writes CIEL.
As for arguments that polymer-wrapped agrochemicals are a boon to farmers, CIEL’s report found that “microplastic accumulation is occurring at a rate up to 50 kilograms per hectare (more than 40 pounds per acre) per year, affecting soil ecosystems, bacterial composition, and organisms—all prerequisites for plant health.”
Global demand for and production of SRFs, CRFs, and other such soil “supplements” is surging thanks to their “aggressive promotion” by Big Agriculture as climate-friendly and sustainable. Based on annual projected market growth of 6%, CIEL estimates the value of these additives will reach US$3.3 billion by 2026.
The group is urging governments everywhere to “close regulatory gaps and comprehensively ban the intentional use of microplastics” in agriculture and other industries. “We do not have to wait for more research,” said report co-author and senior CIEL attorney Giulia Carlini. “Decision-makers should use the precautionary principle to take urgent action and implement a wide range of measures that prevent future harm.”