Understanding the hazards induced by microplastics in different environmental conditions

Microplastics that are chemically and physically changed by exposure to environmental stress are emerging as a potential hazard to human health. Research on plastics exposed to long-term environmental stress is fundamentally needed. In this study, four plastics (acrylonitrile butadiene styrene [ABS], polyvinyl chloride [PVC], polystyrene [PS], and polyethylene [PE]) were selected to describe nature-derived microplastics and to analyze their chemical/physical changes, which are potential hazards to the human health, by environmental stress. To mimic the microplastic exposed to long-term environmental stress, we used accelerated aging, lab-scale aging in the environmental conditions((1) UV (2) enzyme (3) seawater). To quantify the percentage of the microplastic size changes, the image patterns of the generated microplastics were converted into numerical values using image-j. The size of the microplastics was reduced by at least 32% in (3) seawater environmental conditions. PE was reduced by at least 46% compared to the size of the bare sample in the environmental conditions. Significantly, the size of the PE has decreased by more than 87% in (3) seawater environmental conditions; also, chemical composition change (-O-CO-/-OH group formation) but not crystallinity changes through infrared and thermal analysis. Therefore, our results suggest that microplastic (PE) exposed to the ocean induces the potential hazards to affect human health.