How Can Microplastics Harm Marine Life?

Most studies concerning the harm of microplastics towards health and impediments to biological processes examine marine animals most thoroughly. Given that marine organisms eventually make their way up the food chain, and the fact that some of these species have similar biological makeup as humans, it is no wonder scientists are exerting so much energy into the analysis of these particles in aquatic organisms.

ScienceDirect features a research paper discussing the effects of trace elements adsorbing to microplastics, and how this may lead to increased toxicity and transmission of harmful chemicals throughout our environment. In one study, freshwater species called zebrafish were found to have ingested and accumulated plastics under five microns in their “gills, liver and gut after 7 days exposure.” In other instances it has been seen that the accumulation of PCBs from ingested plastics have been identified in certain aquatic organisms (scientists have noted that there is still not substantial evidence on negative health effects due to this intake). The death of many of these fish have been linked to complications in their metabolic processes, increased accumulation of lipids in their livers, and inflammation because of the accumulation of these plastics and the various substances adsorbed to them. This is just one of many cases in which aquatic organisms are extremely put at risk due to microplastic pollution. Health effects as dire as these cause scientists to wonder whether we may face similar health impediments as a result of ingesting microplastics on a daily basis.

Sea birds are especially at risk of plastic pollution through direct ingestion of plastic material and indirect digestion by bioaccumulation up the trophic levels. With 44% of marine birds having ingested plastics, according to researcher Lauren Bradley and coworkers, these birds are susceptible to medical complications directly from plastic particulates and the increased adherence of harmful pollutants (i.e, metal debris) which can lead to fatality of these birds.

Published in Nature, a recent discovery by Mexican researchers, shows that macroplastics were identified in crops given to chickens, in chicken feces 83.55% of plastics found were macro particles, and in earthworm gizzards microplastic particles were between 80-90%. This evidence is a perfect portrayal of just how continuous and pervasive the cycle of plastic pollution can be, and this may indicate the idea of plastic pollution travelling through the food chain.

There are no organisms within the food chain safe from the dangers of microplastics. They are entangled by, swimming with, and ingesting microplastics at astomnishing rates.