Plastics are very commonly used around the world. They get broken down into smaller fragments of microplastics upon exposure to ultraviolet radiation, wind, or water erosion (He at al., 2018). Many of us may be familiar with the plastic problem in oceans and other water bodies, however, they are also evident in forests, particularly within soil environments. Like how plastics cause harmful effects to marine and freshwater environments, in terrestrial environments, they affect soil structures, altering soil bulk density, pore spaces and particle interaction, and water holding capacities (Machado et al., 2018; He et al., 2018). Such changes may affect the moisture levels within the soil, impacting evapotranspiration, and hence, affecting ecosystem services and climate change (Machado et al., 2018).
Soil microbes are important in catalysing many of these biogeochemical transformations that produce important ecosystem services to humans. Hence, the biophysical environment of these organisms is very important. Good soil structure also promotes carbon sequestration where normal biogeochemical processes promote the growth of biodiversity (i.e. growth of flora and fauna within and above soil environments), which helps to decrease atmospheric carbon dioxide levels (Machado et al., 2018). However, alterations to soil structure disturb the environmental condition these organisms are living in, hence affecting their growth and functions.
Microplastics within the soil are stored, translocated, eroded, and degraded into smaller pieces, and these fragments will eventually get leached into groundwater, flowing into water bodies. During this process, soil microbes within soils may ingest these plastics, and humans drinking water will take in these microplastics as well, and hence may cause health problems (He et al., 2018).
References:
de Souza Machado, A. A., Lau, C. W., Till, J., Kloas, W., Lehmann, A., Becker, R., & Rillig, M. C. (2018). Impacts of microplastics on the soil biophysical environment. Environmental science & technology, 52(17), 9656-9665.
He, D., Luo, Y., Lu, S., Liu, M., Song, Y., & Lei, L. (2018). Microplastics in soils: analytical methods, pollution characteristics and ecological risks. TrAC Trends in Analytical Chemistry, 109, 163-172.