The manufacturing process and consequent occupational health and environmental risks associated with the use of plastic waste in construction bricks in small-scale recycling plants

The rapid escalation of plastic production has prompted researchers to seek innovative and sustainable methods for recycling plastic waste to prevent its accumulation in landfills and mitigate its adverse effects on the environment and human health. One way is by incorporating plastic waste into construction materials. This study imparts a review on the application of plastic waste in the production of construction bricks through mechanical recycling processes, with a specific focus on compiling information on the manufacturing process as well as identifying potential emissions, occupational health hazards, and environmental risks. Through a review of 100 existing empirical studies, including those available in open-access journals specifically relevant to the study's focus, it became evident that there is limited research investigating the emissions, occupational health impacts, and environmental risks associated with the production of bricks from plastic waste. Due to this information gap, the study extrapolated health risks and environmental impacts from comparable mechanical recycling processes. Our findings indicated that the manufacturing process, which consists of plastic collection, sorting, washing, drying, shredding, melting or extrusion, cooling, and molding, is likely to emit several air pollutants, including but not limited to heavy metals, persistent organic pollutants, particulate matter, and volatile organic compounds. Individuals involved in the production of plastic-waste bricks likely face a heightened risk of adverse health outcomes, particularly in settings where appropriate safety measures and control mechanisms are lacking. While the scientific literature currently offers a limited examination of the environmental impacts stemming from these pollutants, the research identified significant concerns related to microplastic presence in wastewater and heavy metal contamination in nearby soil and sediments. This study recommends that small-scale recycling operations mandate the use of personal protective equipment, implement adequate control strategies such as general and local ventilation systems, and prioritize the recycling of plastics known to pose minimal risks to human health. There is a pressing need for further research to accurately characterize the emissions produced during the manufacturing process and to comprehensively evaluate the consequent health and environmental hazards.