It becomes more and more difficult to navigate a food system that is influenced in so many ways by human activity. Modern agriculture and pollution both present huge issues with respect to food safety. For decades now the number of foods that appear safe to eat regularly has dwindled. PCBs and dioxin were initial contaminants that proved to be even more damaging as endocrine disruptors than any scientist had anticipated. Later, a variety of pesticides and agrochemicals started showing up on plates across America, most of which remain largely unstudied. More recently, the routine disposal of trash, combined with non-point, runoff pollution, has resulted in a literal plastic soup in almost every ocean examined.
While the effects of this on the marine ecosystem are apparent (birds, sea turtles, and sea mammals have demonstrated a wide variety of physiological damage from ingesting so much plastic), the impact on humans that are bioaccumulating these microplastic particles when eating seafood is less known. We do know that many plastic metabolites are xenoestrogens and can potentiate the role of estrogen in the development of estrogen-related cancer. We also know that plastic particles can disrupt the balance of flora in the intestine. Numerous other relationships have been found and few are benign.
Although eating smaller fish and choosing species lower on the food chain has proved effective in decreasing consumption of other contaminants such as mercury and PCBs, microplastics are so pervasive in the marine ecosystem that even this approach may not be enough. Microplastic pollution is found in significant amounts at every trophic level. Plankton, everything that feeds on plankton, all the way up to the tertiary conumers: whales, sea mammals, and humans.
~ John Bagnulo MPH, PhD.
To read more, here are the very eye-opening findings:
https://www.scientificamerican.com/article/sea-unworthy-a-personal-journey-into-the-pacific-garbage-patch-slide-show/
Sharma and Chatterjee. Microplastic pollution, a threat to marine ecosystem and human health: a short review. Environ Sci Pollut Res Int. 2017 Aug 16
Collard F et al. Microplastics in livers of European anchovies (Engraulis encrasicolus, L.). Environ Pollut. 2017 Oct;229:1000-1005
Jovanović B Ingestion of microplastics by fish and its potential consequences from a physical perspective. Integr Environ Assess Manag. 2017 May;13(3):510-515.