An Endocrine Disrupter Cocktail and a Side of Nanoparticles: Are Plastics Harming Our Health?
by Judith Humble
The world is recognizing the immense harm that disposable plastics inflict on the environment and on living creatures who share our planet. Alarm over these developments has varied in degree. While some people have begun taking steps to reduce plastics, most continue accepting multiple forms of these products into their daily lives. However, as our cradle-to-grave exposure continues to increase, scientists are researching long-term effects of plastic pollutants on human health. Their targets are microplastics and endocrine disrupting chemicals. Their findings are alarming and hard to ignore.
Microplastics: These particles are created by weathering and breakdown of plastic objects, including but not limited to disposable plastics, clothing, cosmetics, plastic products, and packaging. They are also intentionally added to some cosmetics and cleaners. They represent a diverse class of contaminants, spanning five orders of magnitude in size, developed in various shapes (spheres, fragments, fibers), and having a complex chemical composition. At present, they are found in water, soil, various creatures in the food chain, and as particulate pollution in the air.
Microplastics enter the body through inhalation and ingestion. Scientists have determined that larger particles are likely excreted from the body with minimal harm. Concern is focused on the smallest particles, which can cross the epithelial barriers of lungs and intestines, to take up permanent residence in the body. These nanoparticles can migrate systemically to the lymph and circulatory systems, eventually reaching the brain, and the placenta in pregnant women. Once internalized, they may cause physical, chemical, and micro-biological toxicity. Results may include cellular damage, inflammatory and immune reactions, DNA damage, as well as neurotoxic and metabolic effects. A research project conducted by the World Wildlife Federation determined that we may be consuming up to 5 grams of nanoparticles weekly, or about the amount of a shredded bottle cap. A yearly intake might total 250 grams of plastic, enough to create a heaping mound on a dinner plate.
While negative effects have been found in high exposure situations (workers in plastics plants), scientists studying the impact of micro-particles say that even small quantities may have a lifetime cumulative effect. It is noted that many knowledge gaps are present, and that we are in serious need of more advanced research. With plastic becoming ever more abundant, scientists say that it is crucial for us to understand the role of microplastics in the global disease burden.
Endocrine Disruptors: Plastics contain and leach hazardous chemicals, including endocrine-disrupting chemicals (EDCs) that threaten human health. EDCs disturb the body’s hormone systems, and can cause cancers, diabetes, reproductive disorders, and neurological impairments in developing fetuses and children. A report by the Endocrine Society and the International Pollutants Elimination Network describes a wealth of evidence supporting direct links between toxic chemical additives in plastics and specific health impacts to the endocrine system. Known EDCs that leach from plastics include Bisphenol A, Phthalates, polyfluoroalkyl substances (PFAS), and dioxins, all used extensively in packaging, food production, children’s toys, textiles, and cosmetics.
Shanna Swan, a noted environmental and reproductive epidemiologist, has studied EDCs for over two decades. She and co-author Stacy Como (science journalist), recently completed a book on the dangers that EDCs may pose to human fertility if present trends continue. Her alarming findings are described in Countdown: How Our Modern World is Altering Male and Female Reproductive Development, Threatening Sperm Counts, and Imperiling the Future of the Human Race.
Swan’s work on falling sperm counts attracted worldwide attention in 2017. She recorded a decrease in sperm count for men in Western countries of 59% between 1973 and 2011. She also found that quality plummeted, with more odd-shaped sperm and fewer with the swimming strength needed to fertilize eggs. Most importantly, she noted that these impaired sperm carried damaged DNA.
Furthermore, Swann found that men were experiencing erectile dysfunction at earlier ages, with a quarter of those in her sample having ED before age 40. For women, she noted that the miscarriage rate had increased by 1% yearly over the last two decades. In addition, Bisphenol A, used in many hard plastics, is known to interfere with both conception and pregnancy. After harvesting information from hundreds of published studies, Swan concludes that future generations may face a harsh reality with reproduction challenges, and that artificial reproduction technologies may become widely needed for conception.
Swan expresses concern that these disturbing findings have not sparked more rigorous environmental policies. He advocates for stronger regulation and a higher standard for testing the chemicals added to our daily lives. Until stronger policies are in place, she urges minimizing the use of plastics and other products containing EDCs.
In conclusion, scientists studying the impact of plastics on human health are consistent in calling for more research to accurately assess the risk factors for disease. They point out that this is especially crucial in light of an anticipated increase in the production of plastic products in coming decades, and note that findings will be critical to the development of effective health policies. Until these risks are better understood, Sierrans might heed the advice of Shanna Swan, who recommends purging harmful chemicals, and plastics containing chemicals, from our daily lives.
Sources:
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“Plastics Pose Threat to Human Health” (Science News); Dec. 15, 2020: www.sciencedaily.com/releases/2020/12/20121513242.htm
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“Microplastics and Human Health; ” A. Dick Vethaak and Juliette Legler (Science, Feb. 12, 2021 (Vol. 371, pp. 672-674): https://science.sciencemag.org/contnt/371/6530/672.full
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“The Everyday Chemicals That Might be Leading Us to Extinction (New York Times): Bijal Trivedi, March 5, 2021: http://www.nytimes.com2021/03/05/books/review/shaana-swanpcount-down.html
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“United Nations Panel Calls Endocrine Disrupters a Global Threat (Scientific American); Brian Bienkowski; Feb. 19, 2013: https://www.scientificamerican.com/article/united-nations-panel-calls-hormone-dispruptors-global-threat/
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“How much plastic are you eating?” (Reuters/Environment); Reuters’ Staff: Dec. 8, 2020 https://www.reuters.com/article/us-environment-plastic-diet-wider-image/how-much-plastic-are-you-eating-idUSKBN28I16J