Sources, health risks, environmental implications, and management strategies of microplastics with a focus on landfill leachate

Plastic waste is one of the most common types of waste found in municipal solid waste (MSW), that ends up in landfills. Various physical, chemical, and biological processes can transform plastic waste into microplastics (MPs), which are the plastic particles less than 5 mm in size. MPs have unveiled significant threats to human health and the environment. Since landfill leachate is a notable source of both primary and secondary MPs, this paper addresses the existing knowledge gap by reviewing studies on MP detection in landfill leachates from domestic and international sources. The review covers the abundance, characteristics (such as polymer type, size, color, and shape), also the health and environmental risks associated with MPs. It also discusses the effectiveness of current leachate treatment plants in removing these particles. Furthermore, the implications of nanoplastics (NPs), their detection, and the challenges faced by existing treatment processes are examined. While most studies focus on MP detection and removal, there is a pressing need for further research on NPs and their fate in landfill leachate effluent, which is eventually discharged into aquatic environments. Management strategies for MPs in landfill leachate are compared across different treatment technologies. Additionally, some critical topics and future perspectives are proposed to better understand the real-world effects of MPs in human health-related risk assessments and toxicological thresholds.