Microplastics entry routes into Humans, possible health effects, laws, and policies: A review

Our environment is filled with tiny byproducts of plastic smaller than 5 mm, known as microplastics (MPs). Recently, MPs have been identified in human blood and faeces, and within vital organs such as the liver, lung, and kidney. Even so, limited studies have been done on the primary pathways by which MPs enter the body. This study reviews the pathways and potential health effects of MPs in humans, MP regulatory laws and policies. 67 research publications on the routes by which microplastics enter the human body, their possible effects on humans, and the laws and policies for handling MPs, published between 2014 and 2024, were chosen and examined from PubMed, Google Scholar, the Nature database, and Web of Science. First, it was observed that food, drinks, air, and dental products are the dominant pathways of MPs into the human body. Second, it was observed that MPs in humans can be destructive to the digestive system, liver, kidneys, neurotoxicity, endocrine system, respiratory system, cognitive behavioral changes, anxiety, and inflammation of the hippocampus, and a memory organ. Third, more MP (microplastic) laws and regulations which have been passed and implemented in several countries in Africa, Asia, Europe, and America. These includes bans on the sale of plastic products and outlawing the use of microbeads in personal hygiene products. However, future research is necessary to fully understand the accumulation patterns, and long-term effects of MPs in humans because of the complex relationship between these MPs and human health.