Assessing the Fate, and Environmental Impact of Plastics in Soil and Crop Ecosystems Using Isotopic Techniques

Plastics (P) are widely used by people, and its production has increased from 1.7 million metric tons in 1950 to 359 million metric tons in 2018. Despite the remarkable benefits of plastics to society, there are increasing concerns associated with the vast amount of plastic entering our environment, where it is degraded to microplastics (MP), particles less than 5 mm in diameter. Most of plastics produced each year ends up in the environment and the soil acts as a log-term sink for these plastic debris before some of them finding its way to the aquatic ecosystem. According to a recent report by the United Nations’ Food and Agriculture Organisation, the earth’s soil may be more saturated with plastic pollution than oceans and an estimated 80% of plastics found in the marine environments are first disposed on land. There is therefore an urgent need for better understanding of the turnover, fate, latest methodology development for sampling and analysis, its environmental impact on soil and crop eco-systems of P and microplastics MP. 

This Coordinated Research Project (CRP) aims to assess the fate, dynamics and impact of microplastics in agricultural soils and ecosystem services using compound-specific stable isotopes (CSSI) and stable isotope Raman micro-spectroscopy (SIRM). The project also aims to assess the rate and identify the environmental drivers of microplastics degradation. The need for this project is pressing because more than 30% of the world’s plastic waste is disposed inappropriately, with most of it ultimately ending up in soil. FAO and UNEP consider soil pollution with microplastics an emerging environmental issue with serious consequences for soil carbon turnover and greenhouse gas fluxes. Isotopic methods, proposed in the project, can determine the final products of microplastics decomposition in soil and the environmental conditions optimal for reducing microplastics debris in soil.  The CRP will also provide tools and recommendations that will benefit and help Member States’ microplastics policies and management strategies and contribute to FAO’s Action plan on plastics in agriculture.