Legacy landfill-derived microplastics: Terrestrial matrix pathways, spatio-temporal dynamics, and environmental risks

Abstract

Microplastics (MPs) represent a widespread and persistent threat in terrestrial environments, which compromise ecosystem integrity, contaminate food webs, and pose significant risks to human health. This review systematically discusses current knowledge on MPs resulting from legacy waste and landfills in India. Spatio-temporal dynamics and matrix-wise occurrence of MPs across landfill leachate, soils, sediments, compost, and air are presented. Literature indicated that MPs migration is influenced by seasonal hydrology, atmospheric deposition, landfill leachate infiltration, and agricultural amendments, leading to complex vertical and lateral distributions. Diverse polymer types, predominantly polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), with fibers and fragments are the most common morphologies of MPs as clearly evident from various studies. The widespread presence of MPs in various matrices further highlighted under explored pathways of terrestrial contamination and potential food chain transfer. Despite policy advancements under frameworks such as the Plastic Waste Management Rules and Swachh Bharat Mission -Urban 2.0, the integration of MPs monitoring and mitigation into national waste and soil health guidelines is still evolving. There remains an opportunity to develop generate comprehensive long-term field data, specific standardized protocols, and fully incorporate MPs considerations into remediation and circular economy initiatives. This review signifies the importance of trans-disciplinary research, improved technological interventions, and targeted policy actions to address MPs contamination in India's terrestrial ecosystems. The findings aim to inform decision-makers and researchers in developing robust, context-sensitive strategies to mitigate MPs pollution, safeguard environmental quality, and protect public health.