Microplastics:ALL That Glitters Is NOT Gold

Particulate plastic inputs to terrestrial and aquatic ecosystems cover range of particle size including microplastics and nanoplastics. Particulate plastics encompass a group of plastic polymers, and there are two types of particulate plastics that can enter the environment. Primary particulate plastics are manufactured and are a direct result of anthropogenic use of plastic-based materials. Secondary particulate plastics are plastic fragments resulting from the breakdown of larger plastic pieces. While wastewater discharge is a major source of particulate plastic input to aquatic ecosystem, application of biowastes such as biosolids and compost leads to particulate plastic input to soil. The UNEP identified that large quantities of particulate plastics found within the marine environment have originated from land-based sources. Both primary and secondary particulate plastics persist both in terrestrial (i.e., soil) and aquatic (i.e., marine and freshwater) ecosystems.

Particulate plastics input to soil can have both beneficial and detrimental impacts on soil characteristics and organisms. For example, polyacrylamide is used to promote flocculation and soil aggregation, thereby mitigating soil erosion. Particulate plastics impact environmental contaminant interactions in soil by serving as a vector for contaminant transport and by altering contaminant bioavailability in soil. As a vector, particulate plastics release toxic chemicals added during the manufacture of plastics to the soil environment. Despite the link between marine-based and to land-based sources of particulate plastic inputs, the majority of scientific research on particulate plastics has focused on their effects in aquatic environments. This presentation covers the sources, distribution and impacts of particulate plastics in soil.