Impact of microplastics on soil health: a review

Rogers Wainkwa Chia 1,2, Jin-Yong Lee 1,3* 1 Department of Geology, Kangwon National University, Chuncheon 24341, Republic of Korea 2 Research Institute for Earth Resources, Kangwon National University, Chuncheon 24341, Republic of Korea 3 Research on Microplastics in Groundwater (RMPG), Kangwon National University, Chuncheon 24341, Republic of Korea *Corresponding author: E-mail: hydrolee@kangwon.ac.kr Soil a slim layer of matter that envelops the earth's surface, created through weathering of rocks and a groundwater natural filter of contaminants is very important to mankind. Recently, some studies have shown that the occurrence of microplastics in soils around the world is on the rise. However, these studies do not show a clear pattern of the impacts of microplastics pollution on soil health. It is necessary to clearly show the severity of microplastic pollution on soil health. Here, we have selected papers published internationally in the past ten years and reviewed soil microplastic pollution on soil physicochemical indicators of soils. Strangely, soil contamination by microplastics cause an increase in soil pH, temperature, and porosity. In some other cases, this microplastic pollutants can cause a decrease in soil hydraulic conductivity and cation exchange. In addition, this review shows that soil water holding capacity could either increase or decrease following soil microplastic contamination in some instances. We also discussed the specific microplastic polymers that cause soil health damage. Even though these papers show some evidence of soil microplastic impact on soil health through soil physiochemical alterations, more studies are needed to evaluate other soil indicators especially not studied yet. This research aims to inspire us to properly manage soil health for the benefit of mankind and the environment. It was supported by Korea Environment Industry and Technology Institute (KEITI) through Measurement and Risk assessment Program for Management of Microplastics Program (or Project), funded by Korea Ministry of Environment (MOE) (2020003110010). The study was also funded by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education of the Korean government (No. 2019R1A6A1A03033167)