Perspectives on ecological risks of microplastics and phthalate acid esters in crop production systems

Microplastics (MPs) and phthalate acid esters (PAEs) co-occur as emerging contaminants of global importance. Their abundance in soil is of increasing concern as plastic-intensive practices continue. Mulching with plastic films, inclusion in fertilizers, composts, sludge application, and wastewater irrigation are all major and common sources of MPs and PAEs in soil. Here, we review studies on the concentration and effects of MPs and PAEs in soil. While there is limited research on the interactions between MPs and PAEs in agroecosystems, there is evidence to suggest they could mutually affect soil ecology and plant growth. Therefore, we propose new research into 1) establishing an efficient, accurate, and simple method to quantify different types of microplastics in soils and plants; 2) exploring the behavior and understanding the mechanisms of co-transfer, transformation, and interactions with soil biota (especially in vegetable production systems); 3) assessing the risk and consequences of combined and discreet impacts of MPs and PAEs on plants and soil biota, and 4) preventing or reducing the transfer of MPs and PAEs into- and within- the food chain.