Impacts of microplastics on terrestrial plants: A critical review

Microplastic (MP) pollution is an important environmental problem owing to its widespread use, long residence time, and overall persistence. MPs threaten the health of humans, animals, and plants. However, studies on the effects of MPs on terrestrial plants are less common compared to those conducted in aquatic systems. This review discusses the sources of MPs in terrestrial ecosystems, their effects on C and N cycling in soils, and the impact of MPs on terrestrial plants, and focuses on plant growth and the potential risks to human health. MPs affect plants and their performance by altering soil structure, microbial activity, nutrient immobilization, transporting contaminants, and causing direct toxicity. Chemicals, such as plasticizers, additives, and colorants, in MPs may negatively affect ecosystems and their inhabitants, and MPs may interact with a wide array of pollutants, including pesticides, heavy metals, and antibiotics. These impacts vary as a function of soil type, plant species, and MP type. Future research efforts should focus on interaction complexity, uptake mechanisms, and impacts on plants at multiple spatiotemporal scales, while concurrently considering their effects on food chains and human health.