By John Larson and Joel Tallaksen
A recently identified concern in agriculture is the contamination of ag lands and food products with microplastics. Defined as plastic particles less than one millimeter in size, these long-lasting microplastic particles are now being identified in soil and agricultural systems globally. Microplastics are the breakdown products of plastic as it ages and is exposed to the environment. Typically, this breakdown produces fragments and fibers of plastics that can be difficult to see without a microscope.
Currently there are more than 9000 commercially available plastic polymers and over 4000 unknown chemicals related to plastic packaging. Though agriculture is not necessarily the biggest contributor to the global microplastics problem, there is concern that contamination of food and food production systems could have long-lasting health and environmental implications. A number of studies have found microplastics trapped within farm-grown fruits and vegetables, as well as fish and other gathered foods.
The full impacts of microplastic contamination on human health are not well understood. A major concern is that microplastics can contain other hazardous contaminants that can impact human and ecosystem health. One group of associated toxins is per- and polyfluorinated alkyl substances (PFAS) also called ‘Forever Chemicals’. Another potential toxic chemical in microplastics is Bisphenol A. These man-made chemicals are relatively new, but are found in low concentrations in human, terrestrial, and marine wildlife blood samples globally. Exposure to high concentrations of these chemicals is known to impact human health, but it is not clear how long-term, low-level exposure could impact health.
While agriculture’s use of plastic is small in comparison to other sectors of the economy and consumer use of plastic, farmers should take the lead to reduce microplastic contamination in agricultural systems. Plastics are indispensable in modern agriculture and have enabled advances in efficiency across many agricultural disciples. Farming is heavily dependent on plastic for greenhouse and polytunnels, drain tile, irrigation, storage for feed and fertilizer, silage and bale wrap, and mulching crops. The key to reducing ag-related microplastics is to properly dispose of used plastics, recycle when possible, and find alternatives to plastic where available. To some degree, this has already occurred as farmers have switched to seed totes in places of plastic-lined bags and reusable palletized chemical containers in place of smaller jugs. In horticulture, new paper-based mulches and potting materials are beginning to be tested that can reduce plastic use.
A key component of reducing ag-related microplastics is the proper disposal of plastic when the plastic has fulfilled its role. Recycling plastic where available or using the regional waste management system will prevent the on-farm degradation of plastic that leads to more microplastic contamination. The Minnesota Department of Health operates an empty pesticide container recycling program in cooperation with the AG container recycling Council. Additionally, customers who purchase crop protection pesticides in plastic containers can return containers to the place of purchase. These programs allow farmers to recycle waste that would otherwise be disposed of in a less environmentally friendly manner. Other regional and county-based options are available that can accept plastic in some parts of the state.
Though efforts by agriculture to reduce microplastics in food will not stop microplastic contamination from off-farm air and water borne microplastics, the effort shows consumers that farmers care about the products they sell and their customers.
As part of an effort to better understand the issues of microplastics and agriculture, the University of Minnesota, West Central Research and Outreach Center has recently started gathering available data from across the country to identify how Minnesota’s agricultural sector may be impacted by microplastic contamination issues and how they can be mitigated. This work is funded by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).