Abstract:
As a new type of global environmental pollutant,microplastics have attracted increasing attention. However,there is still a lack of exposure level of microplastics and their potential health hazards. This review aims to sort out the pathways and levels of human exposure and sum up the adverse effects of microplastic induced by exposure on mammalian model animals -- mice from in vivo and cultured cells in vitro. The results showed that :(1) Humans can ingest microplastics through the digestive tract,respiratory tract,and skin contact,and oral ingestion is the most important exposure pathway. (2) Microplastics were detected in various tissues,organs,and metabolites of the human body,ranging from 0 to 134.3 per gram. (3) Animal experiments have shown that microplastics can accumulate in the heart,liver,spleen,lung,kidney,testis and other organs through blood circulation,causing an inflammatory response,oxidative stress,immune damage,flora disorder,metabolic disorders,and even produce intergenerational effects. (4) Cell experiments have shown that microplastics with small particle sizes can penetrate cell membranes and enter the cytoplasm,causing changes in cell morphology and function,resulting in decreased cell vitality,affecting cell growth and proliferation,and inducing ROS generation and even DNA damage and other cytotoxic effects. The toxicity of microplastics may be related to its type,particle size,concentration and type of test substance. Further studies on toxic accumulation and changes of microplastics and their adsorbents in the food chain transfer process under low environmental concentrations can be strengthened,as well as epidemiological studies,providing a theoretical basis for further elucidating the potential toxicological mechanism of microplastics and assessing human health risks in the future.