Microplastics pollution in the terrestrial environments: Poorly known diffuse sources and implications for plants.

Area of Science:

• Environmental Science
• Ecotoxicology
• Soil Science

Background:

• Microplastic (MP) research in terrestrial environments is nascent, with poorly understood diffuse pollution sources.
• Tyre and Road Wear Particulates (TWRP) are significant contributors to urban MP pollution, with particles entering roadside soil and runoff.
• Ponds and agricultural lands are identified as sensitive ecosystems harboring considerable MP concentrations.

Purpose of the Study:

• To review current knowledge on diffuse microplastic sources in terrestrial ecosystems.
• To investigate the presence, absorption mechanisms, and effects of microplastics in plants.
• To highlight the challenges in quantifying MP inputs and understanding their transport in soil.

Main Methods:

• Literature review of existing studies on terrestrial microplastic pollution.
• Analysis of research on microplastic sources, including urban and agricultural environments.
• Examination of studies detailing microplastic presence and effects in plants and aquatic-terrestrial connecting ecosystems.

Main Results:

• Tyre and Road Wear Particulates (TWRP) significantly contribute to MP pollution, with substantial amounts remaining in roadside soil.
• Ponds and small water bodies show considerable MP levels in both water and sediment.
• Edible plants accumulate microplastics and nanoplastics, leading to concerning Estimated Daily Intakes and adverse effects on plant physiology and nutritional value.

Conclusions:

• Diffuse MP sources, particularly TWRP, pose a significant threat to terrestrial ecosystems.
• MPs are present in various terrestrial environments and are absorbed by plants, with potential ecological and human health implications.
• Further research is crucial to understand MP transport, quantify diffuse sources, and assess the full impact on ecosystems and food safety.