Microplastics and health hazards: gastrointestinal risk assessment across a multi-species perspective

Abstract Plastic is now a globally acknowledged pollutant. The current annual production of plastic worldwide is over 400 million tonnes, of which more than 40% is contributed by single-use plastic, resulting in plastic waste. This plastic garbage degrades into finer particles termed microplastics (less than 1 mm) and nano-plastics (less than 1 µm), together known as micro-nano-plastics (MNPs). Because of their endurance, they may remain in the environment for several decades, and their low density can easily be dispersed by wind and sea waves, often traveling thousands of kilometers. Due to these characteristics, MNPs are omnipresent now. Humans get exposed to these MNPs regularly, mainly through ingestion, inhalation, and dermal contact. Huge quantities of MNPs have been reported in the ocean around the globe, and through this, they enter the seafood and further into humans. Additionally, MNPs have been detected in processed food and beverages such as beer, tea bags, and table salt. Once MNPs enter the body, they accumulate in the tissues, enter the bloodstream, and affect various cellular pathways. So, the hazard assessment results from various studies on MPs and NPs are diverse and sometimes conflicting, most likely due to the use of research models and the diversity of the MNPs (varying size, shape, and composition). Therefore, considering these parameters this review will thoroughly evaluate the possible impact of MNP exposure on the gastrointestinal system and further amplifications on human health. Graphical Abstract