Plastic is a wicked problem, without a doubt. Stories of seals choking on the plastic loops used to hold soda cans together, or of birds dying when they ingest too many plastic fragments should be a call to action, regardless of our plastic addiction. But when we focus on marine plastic’s direct impact on human health, and not just its indirect impact through the degradation of the environment, we find that plastic is a serious threat to our own health, and needs to be addressed for these implications as well as our concern for marine wildlife.
The chemicals used in plastic production have been found in the human population through biomonitoring, and have also been correlated with harmful effects upon human endocrine systems, including reproductive health. [1] These chemicals are primarily transferred to the human population by skin contact, ingestion, and inhalation, and are found in objects used in everyday life, from packaging to drink containers (such as BPA). [2]
But direct contact with plastics is not the only worrisome health risk. Ingestion of seafood ought to be a concern as well. Without a doubt, chemicals associated with plastic pollution are harmful to wildlife, and can be affecting native populations. [3] The depletion of certain marine species will limit the human diet and cause detriment to cultures which place significance upon certain species, whether dietary or traditional. But looking at a shorter-term impact, the consumption of plastic-pellet-ingesting marine life can carry toxic chemicals straight into our diners. [4] Plastics can act as carriers of industrial byproducts and other hazardous chemicals in seawater, absorbing them and then carrying concentrated amounts into fish and other marine life, and from there, into our diet. [5] Additionally, through the process of biomagnification, the levels of toxins collected in smaller fish that consume contaminated plastic pellets are amplified in larger fish which eat many smaller fish. [6] This means that we, at the top of the food chain, are getting the highest concentration of toxins when we eat the larger fish.
A study performed on Japanese rice fish, fish about one inch long, showed that of the fish who were exposed to plastic (polyethylene) pellets that were soaked in the waters of San Diego Bay (as opposed to those with no plastic pellets, and those with clean plastic pellets), 74% showed severe depletions of glycogen, and 11% showed widespread death of individual liver cells. [7] These small fish are an example of the supporting population of food webs, of which we are at the top. For similar reasons, the Environmental Protection Agency recommends that people limit their consumption of predatory fish such as tuna. These fish accumulate high levels of poisons through their diets of smaller, contaminated, fish. [8] By eating many larger fish, we too would accumulate toxins in our body, which put stress on liver health.
Put simply, toxins are absorbed from the ocean’s pollution by small plastic pellets, which are appetizing to small fish. These small fish are appetizing to larger fish, who get loaded with the toxins that the small fish were carrying. These larger fish are appetizing to us, just the next step up in the food chain. And the health risks associated with this chain of toxin transferral are not so appetizing.
[1] Thompson, R. C., C. J. Moore, F. S. Vom Saal, and S. H. Swan. “Plastics, the Environment and Human Health: Current Consensus and Future Trends.” Philosophical Transactions of the Royal Society B: Biological Sciences 364.1526 (2009): 2153-166. JSTOR. Web.
[2] Ibid
[3] Ibid
[4] Stromberg, Joseph. “How Plastic Pollution Can Carry Flame Retardants Into Your Sushi.” Smithsonian.com. Smithsonian Institute, 21 Nov. 2013. Web. 16 Sept. 2014.
[5] Ibid
[6] Ibid
[7] Ibid
[8] “Fish Consumption Advice.” EPA. Environmental Protection Agency, n.d. Web. 17 Sept. 2014.
