The impact our environment has on us as humans is often underestimated. In fact, there are a lot of things we do not see in our environment but which remain there before our eyes. Those invisible things are often the most dangerous, particularly because we do not see them, thus often leading us to ignore their existence and indirectly their potential toxicity. Endocrine-disrupting chemicals, also referred to as EDCs, are one of those invisible but dangerous things. They have indeed been behind the increase of various diseases amongst us humans over the past few decades. So how does that work and how can we avoid those chemicals in our daily lives? Can we actually avoid them or is it too late? Let’s try and understand this topic and figure out what we can do to improve the current situation.
First, let’s define the nature of EDCs. Endocrine-disrupting chemicals, also referred to as endocrine disruptors, are chemicals that disturb our hormonal system. They can mimic, block, or interfere with the production of hormones in the body. The most common way for us to ingest them is through our food consumption. This means that they can be found in the packaging of our food, in the tools we use to prepare or to cook our meals, or even in the food itself depending on where and how it was grown. EDCs can be found in a myriad of different products, from plastics, to pesticides, or even cosmetics. For instance, American investigative journalist and author of “The Monsanto Papers” Carey Gillam writes in her article titled “New research adds evidence that weed killer glyphosate disrupts hormones”, that “In a paper published in the journal Chemosphere titled Glyphosate and the key characteristics of an endocrine disruptor: A review, a trio of scientists concluded that glyphosate appears to have eight out of ten key characteristics associated with endocrine disrupting chemicals.” She further explains that some of the evidence provided in this research paper suggests that Roundup, Monsanto’s famous glyphosate-based herbicide, has the potential to alter the biosynthesis of sexual hormones. The consequences range from developmental and reproductive problems to brain and immune system dysfunction.
Some common EDCs detected in people include DDT, polychlorinated biphenyls (PCBs), bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), and a variety of phthalates. Indeed, almost all plastic-based products, including those carrying the label “BPA free”, have been found to contain endocrine-disrupting chemicals. Bisphenol A is majorly found in plastic: that means bottles, food containers, dental materials and food cans. Another type of exposure occurs via the use of receipt papers from grocery stores and restaurants, since the paper is often coated with a BPA-containing clay for printing purposes. Dichlorodiphenyltrichloroethane (DDT) is another type of EDC. The latter was first used as pesticide and has been linked to issues in the development of female reproductive organs as well as a decrease in fertility in adult males. As to phthalates, these are commonly found in certain soft toys, flooring materials, medical equipment, cosmetics or even air fresheners. A 2002 public report from the Food and Drug Administration (FDA) in fact states that “Exposure to DEHP has produced a range of adverse effects in laboratory animals, but of greatest concern are effects on the development of the male reproductive system and production of normal sperm in young animals. In view of the available animal data, precautions should be taken to limit the exposure of the developing male to DEHP“. The forms EDCs take are, as we can see, as varied as their consequences on the human body.
One of the most disastrous effects of EDCs can in fact be observed when it comes to fertility and overall health of reproductive organs among both sexes. For males, it has been found out that exposure to EDCs is linked to a significant decrease in sperm count and overall quality of semen. Researchers at the University of Geneva (UNIGE), Switzerland, and epidemiologists from the Institut de Recherche en Santé, Environnement et Travail (IRSET, Rennes, France) have analyzed the potential consequences of EDCs on semen quality of men exposed in utero to those chemicals. Their results, published in the journal Human Reproduction, show that young males exposed in utero to EDCs are twice as likely to have values below the reference-values established by the World Health Organization, both in terms of the semen volume and the total number of spermatozoa per ejaculation. For females, our increasing exposure to endocrine disruptors has been linked to a rise in cases of endometriosis, a chronic gynecological disease characterized by an abnormal development of endometrial tissue outside the uterine cavity. In a 2009 study from Italy, “Pre-natal exposure of mice to bisphenol A elicits an endometriosis-like phenotype in female offspring”, researchers analyzed the impact of developmental exposure to bisphenol A (BPA) during pre- and peri-natal development on female mice genital system: “We found in the adipose tissue surrounding the genital tracts of a consistent number of treated animals, endometriosis-like structure with the presence of both glands and stroma and expressing both estrogen receptor and HOXA-10.” Bisphenols, benzophenones and phthalates thus remain non-negligible threats for mothers-to-be, as well as people in general.
Because hormones are at the center of our body’s functioning, anything that affects, interfere or interact with them can have consequences which do not limit themselves to our reproductive functions. Our hormones, controlled by our endocrine system, are chemicals which coordinate different functions in our body by carrying messages through our blood to different tissues such as our organs, our skin or our muscles. These signals inform our body what to do and when to do it. With this in mind, we can understand the severity of the threat which endocrine disruptors pose to us, because of the importance of the role hormones play in our body. Being exposed to those chemicals can thus cause a variety of health problems, including alterations in sperm quality and fertility (as discussed previously), abnormalities in sex organs, endometriosis (as discussed previously), early puberty, altered nervous system function, immune function, certain cancers, respiratory problems, metabolic issues, diabetes, obesity, cardiovascular problems, growth, neurological and learning disabilities, and much more. In an article from the European Commission dedicated to this very topic, we can in fact learn that “studies in Denmark and USA have suggested that children born in polluted areas have some impairment of memory and intelligence.”
Likewise, when considering this issue from a planetary perspective, it is worth mentioning that endocrine disruptors are not only a threat to us, but to the Earth as a whole. Because of the pervasiveness of those chemicals, adverse health effects have been noticed on wildlife too. The European Commission in fact writes in that regard that “In wildlife, endocrine disruptors have been clearly shown to cause abnormalities and impaired reproductive performance in some species, and to be associated with changes in immunity and behaviour and skeletal deformities.” The consequences include the thinning of eggs amongst birds, the development of male genitalia in female marine Mollusca, the growth of female gonadal tissue and production of vitellogenin (an egg yolk protein) in male fresh water fish from rivers or lakes exposed to treated sewage effluents, as well as an impaired reproductive development and abnormalities of the reproductive system, as observed in alligators in Florida, and in turtles in the Great Lakes, US.
The non-recyclability of a lot of EDC-containing materials is an equally concerning subject, as those chemicals contribute to the pollution of soils. And while we at first tend to think of plastics and other non-recyclable types of packaging materials as main threats, it is important to keep in mind that a great part of the pollution of soils happens via other mediums; the main ones being herbicide and pesticides. In fact, those xenobiotic chemicals have over time altered the composition of soils and the nutritive properties the latter have for plants to grow. While those substances remain fairly regulated within the European Union, we can sadly not say the same about America, where chemical compounds such as glyphosate and chlorpyrifos remain widely used in agriculture. Their effects, although often ignored, are not insignificant. A study published in February 2016 in fact stated that “Pesticide chlorpyrifos acts as an endocrine disruptor in adult rats causing changes in mammary gland and hormonal balance”. Another study’s title from 2009 reads “Glyphosate-based herbicides are toxic and endocrine disruptors in human cell lines”. Another 2013 study from Egypt measured the impacts of the herbicides atrazine and glyphosate on a variety of snails, and concluded that these chemicals caused degenerative changes including azoospermia and oocytes deformation. Although we humans differ at various levels from snails and rats, we have in common certain features, like having hormones or having a nervous system. With this in mind, although each chemical can affect different species in different ways, we can nevertheless fathom the extent to which EDCs pose a threat to us living beings. Likewise, by ridding soils of certain species, we’re also impoverishing their biome and its richness in nutrients, ultimately rendering our soils not only poor but also contaminated.
So what do we do? Although this topic can be quite scary, trembling in fear is not going to bring anything to the table. The first step we can take as people (like in any situation) is identifying the problem, which is what we’ve done here. From there, we can understand what needs to be adjusted. In our daily lives, this means being more vigilant in our consumptions patterns and trying to avoid certain types of products. An easy example would be to start swapping plastic food-containers for glass food-containers. Another one would be to support and encourage allotment gardens in urban areas. Another one could be to buy vegetables and fruits in bulk rather than prepackaged.
In a society where consumerism is at the center of our daily lives, we often forget to take a step back before making a purchase. This can unfortunately cost us our health as well as our wealth. Although the struggle to fight the constant bombardment of ads and marketing moves is real, reshaping our consumption habits is becoming more and more important. Readjusting the way we consume can and will place us in the right path towards sustainability: “Meeting the needs of the present generation without compromising the ability of future generations to meet their needs” as the Brundtland Commission defined it in 1987, is in fact something we people should have more in mind.
Sources
https://usrtk.org/pesticides/new-research-adds-evidence-that-weed-killer-glyphosate-disrupts-hormones/
https://www.sciencedaily.com/releases/2021/03/210319125459.htm
https://academic.oup.com/humrep/article-abstract/36/7/1948/6174711?redirectedFrom=fulltext
https://www.endometriosi.it/wp-content/uploads/2016/05/General-e-Comparative-Endocrinology-168-.pdf
https://ec.europa.eu/environment/chemicals/endocrine/definitions/affect_en.htm
https://www.bfr.bund.de/en/presseinformation/2010/A/endocrine_disruptors__substances_with_harmful_effects_on_the_hormone_system-50525.html
https://www.sciencedirect.com/science/article/abs/pii/S0960076015301126
https://www.sciencedirect.com/science/article/abs/pii/S0300483X09003047
Aude Calloch 