Plastic pollution and its pathophysiological impacts on mammalian cells

The non-natural anthropogenic product, plastic once heralded as a durable, inert, resilient, multipurpose and long-lasting polymer has now become a problem of gigantic dimensions. Plastics are either non-biodegradable or have a very long half-life and hence persist in environment for very long period of time. However, the impacts of physical, biological and chemical forces of nature on plastics break down its bigger pieces into fragments of micro and nano scale thus giving rise to microplastics (MPs) and nanoplastics (NPs). Their persistence in environment has resulted in pollution. MPs and NPs enter zooplankton and microscopic organisms by ingestion and get accumulated in organisms by trophic transfer from prey to predator. Lab simulated studies have demonstrated trophic transfer in food chain. Their presence inside living organisms is worrisome as the organisms cannot digest or even get rid of them by egestion. Detrimental and toxicological effects of MPs and NPs on zooplanktons and plants have been widely studied and documented by many research groups across the world. Studies have shown that the effects may be either direct like accumulation in tissues and obstruction of the gut of organisms or indirect wherein organic pollutants could be adsorbed onto MPs/NPs and then gain entry inside living organisms via ingestion. The present review focuses on the critical question of potential toxicity arising from the uptake or entry of MPs and NPs by mammalian cells. Prevailing research studies data suggest the imminent threat to mammalian tissues. For long-term consequences, the data may be insufficient but speculations hint to a grim situation. This review brings to light the need for more concentrated efforts at the global level to investigate potential cellular and systemic toxicity due to micro-and nanoplastics.