Microplastics (MPs) are a top global concern causing environmental scientists to begin extensive research on the mechanisms of microplastic development. Researchers from Incheon National University, Korea, headed by Prof. Seung-Kyu Kim, explore these mechanisms in their latest study published in the Journal of Hazardous Materials.
"Most studies on MPs have focused on the marine environment, but substantial amounts of MPs can be generated in the agricultural environment via weathering and fragmentation of plastic products used in agricultural practices. We hoped to find out the amount of MPs in Korean agricultural soils and how they change according to different agricultural practices and environmental conditions," says Prof. Kim.
Researchers looked at four soil types corresponding to different agricultural practices: soils from outside and inside a greenhouse (GS-out and GS-in, respectively), mulching (MS), and rice field soil (RS). Scientists also saw an interesting trend with MP size distribution in the soil samples. They found that, unlike GS-out, MS, and RS, GS-in showed an increasing abundance for progressively smaller sizes. They associated this with the "environmental fate effect," causing the removal of MPs by surface-runoff, infiltration, and wind in the GS-in samples.
Prof. Kim states, "Contrary to previous studies which stress on MPs originating mostly from external sources, our study reveals that MPs in agricultural soil can come from external as well as internal sources and that their concentration and sizes can be strongly affected by environmental conditions”.