[Human Accumulation and Toxic Effects of Microplastics：A Critical Review]

The effect of microplastics on the ecological environment and human health has become a topical issue， and research on the risks and harmful effects of MPs on human health in particular has attracted widespread attention. Due to the characteristics of small size， low degradability， and easy migration， MPs continuously migrate from the environment to the human body， and their main exposure pathways are oral ingestion， inhalation， and dermal contact， with the main exposure media being food， drinking water， dust， personal care products， etc. MPs have been detected in organs， fluids， and excreta of digestive， respiratory， cardiovascular， reproductive systems， etc. The abundance range of MPs in the human body is 0-1 206.94 particles per gram. After entering the human body， MPs can cause cytotoxicity， mitochondrial toxicity， DNA damage， cell membrane damage， and other effects on human cells and organs， leading to serious consequences such as local inflammation， ecological imbalance， metabolic disorders， etc.， in various systems. Owing to their small specific surface area， they can also adsorb pollutants such as heavy metals， organic pollutants， antibiotics， pathogens， and harmful microorganisms， causing combined toxicity and immunotoxicity. In the end， we highlighted general deficiencies in existing studies and provided directions for future research on the influence of MPs on human health.