Earth Science, Earth's System, ES 1: Geochemical Cycles (HS), ES 2: Hydrological Cycle (MS), ES 3: Hydrological Cycle (HS), HSus 1: Human Activity (HS), HSus 2: Monitoring Human Impact (MS), HSus 3: Human/Ecosystem Interactions (HS), HSus 5: Showing Human Impact (HS), Human Sustainability

Investigating Microplastics on Land

Microplastics as an emerging threat to terrestrial ecosystems (NOT OPEN ACCESS)

SUMMARY: Though there has been a lot of research on microplastics in aquatic environments, there aren’t studies looking into the effects of microplastics on land. Researchers in this article suspect that there may be more microplastics on land than in the oceans; organisms that live in soil, such as worms and protozoa in the rhizosphere (micro-ecosystem next to plant roots), can consume these microplastic pieces. As plastic breaks down into smaller pieces, they release toxic chemicals that were added during production. The problem right now is that there is no good method to accurately quantify the amount of plastic in a sample. Even more disturbing, microplastics break down further into nanoplastics. These nanoplastic pieces have effects on living cells that are not well studied. The conclusion of this article urges the research community to focus their efforts on understanding this new type of pollution.

LESSON COMMENTS: I used this article when teaching students about primary and secondary pollutants in environmental science class; because terrestrial microplastics affect agriculture, rhizosphere, run-off, water treatment facilities, and other topics that I cover in the first semester, this is a good article to help students understand how biogeochemical cycles work together. Environmental science is extremely complicated, but popular media often focuses on one or two things (fossil fuels and CO2 production). I think it is important students leave the class knowing how complicated the climate change/global warming debate actually is.

de Souza Machado AA, Kloas W, Zarfl C, Hempel S, Rillig MC. Microplastics as an emerging threat to terrestrial ecosystems. Glob Change Biol. 2018;24:1405–1416.