Microplastics in soil pose global threat by acting like ‘Trojan horse’ to deliver toxins

A five-year multinational research project has exposed the global threat posed by microplastics in soil, acting as a "Trojan horse" to deliver toxins. The EU-funded study, involving 227 agricultural fields across 11 European countries, discovered microplastics in all tested soil samples. This revelation highlights the persistence of plastic pollution over time, as it reflects both current farming practices and historical land use.

Microplastics can create a "plastisphere," a hotspot for interactions between plastics, microbes, and agrochemicals, which can amplify the presence of antibiotic-resistant genes. Smaller microplastics tend to adsorb pollutants, microbes, and DNA, leading to a more significant Trojan horse effect. This effect can disrupt critical soil processes, such as nutrient cycles, impacting earthworms, soil organisms, and overall soil health.

Microplastics can also negatively affect plant growth and function, reducing leaf area, chlorophyll content, photosynthetic efficiency, and plant biomass in sensitive crops like lettuce. The presence of microplastics under drought conditions exacerbates these effects, causing plants to perform less well than under either stress alone.

Environmental assessments often consider pollutants individually, but the research emphasizes the need to recognize the combined impact of plastic contamination and other agricultural stressors. The project's findings underscore the urgent need for standardized plastic monitoring, full manufacturer transparency, and risk assessments that evaluate microplastics' interactions with co-pollutants to protect long-term food production and soil health.