Health risk of human exposure to microplastics: a review

Microplastics are emerging contaminants that have been detected recently in most environmental and biological systems, yet their health risk for humans has not been clearly summarized. Here we review human health risk associated with exposure to microplastics with focus on methods of exposure assessment, hazard identification, dose–response assessment, exposure assessment, and risk characterization. Hazards include direct hazards, hazards from contaminants released by microplastics, and hazards from microplastic interactions with surrounding contaminants. Microplastics trigger oxidative stress, disrupt metabolism, interfere with gut microflora and gastrointestinal functions, disrupt hepatic, cardiopulmonary and immune systems, and degrade reproductive health. Some additives leached from microplastics such as phthalates are endocrine disruptors and thus impact reproductive health. The interaction of microplastics with other pollutants in the environment induces varied hazards following synergistic or antagonistic effects.