How does microplastic pollution affect terrestrial food webs?

Microplastic pollution interrupts terrestrial food webs through a mix of physical, chemical, and ecological processes that change how energy and nutrients flow among soil, plants, and animals. Research highlights both direct ingestion by organisms and indirect effects mediated by altered soil properties and contaminant transport. Understanding is evolving but evidence shows real pathways of impact.

Pathways into soils

Microplastics reach agricultural and wild soils from plastic mulches, wastewater biosolids, degraded litter, and atmospheric deposition. Jenna Jambeck, University of Georgia, quantified large global inputs of plastic waste to the environment, establishing the scale of material available to fragment into microplastics. Once in soil, particles persist and accumulate in surface layers where plants and soil fauna interact.

Effects on organisms and food chains

Microplastics affect organisms at multiple trophic levels. Studies by Eduardo Huerta Lwanga, KU Leuven, document ingestion by earthworms and incorporation into soil aggregates, which can change feeding behavior and mobility of detritivores. Olaf Rillig, Freie Universität Berlin, has shown that microplastics alter soil structure and water retention, influencing microbial activity and plant root growth. Physical blockage, abrasion, and changes in gut passage times can reduce nutrient assimilation in invertebrates, while plastics’ sorption of pollutants and release of additives introduce chemical stressors. Mark Browne, University of New South Wales, provided foundational evidence that small plastic particles accumulate in animal tissues, supporting the concept of bioaccumulation and trophic transfer. Chelsea M. Rochman, University of Toronto, has demonstrated trophic transfer of plastics in aquatic food webs, reinforcing concerns for terrestrial analogs where fewer but growing studies indicate similar risks.

Consequences and context

Consequences include disrupted decomposition and nutrient cycling, altered plant growth and crop yields, and potential transfer of microplastics and associated chemicals to livestock and humans through consumed plants or prey. Long-term ecosystem-level effects remain incompletely quantified, but the combination of physical disruption and chemical exposure poses risks to food security and soil health. Cultural and territorial practices matter: regions that apply untreated sewage sludge as fertilizer or rely heavily on plastic mulches may concentrate exposures, while communities dependent on subsistence agriculture face disproportionate vulnerability. Mitigation requires managing plastic waste sources, adapting land management to reduce inputs, and targeted research to link particle characteristics to biological outcomes.