A new report on hormone-related health conditions raises new concerns about the profound threats to human health from endocrine disrupting chemicals (EDCs) that are ubiquitous in our surroundings and everyday lives. The report from the Endocrine Society, the world’s leading scientific and medical experts on hormone-related health conditions, was co-produced with the International Pollutants Elimination Network (IPEN), a global organisation working to protect human health and environmental rights from toxic substances.
“Endocrine Disrupting Chemicals: Threats to Human Health” sums up the state of our scientific knowledge about EDC,” said lead author Andrea Gore, Ph.D., The University of Texas at Austin, and board member of the Endocrine Society. The report presents detailed analyses on exposure to EDCs from four sources: plastics, pesticides, consumer products (including children’s products), and per-and polyfluoroalkyl substances (PFAS), a class of thousands of chemicals known or suspected to be EDCs.
“Over the years, the science on EDCs has really grown, along with our understanding of how important environmental factors - including EDCs - are in disease prevalence and also disease severity. This comes from a convergence of evidence that has grown over the years, based on work in cell lines that might mimic endocrine cell animal models where we can expose animals and then show direct causation of disease by exposure to EDCs. And also from growing evidence from human epidemiology. So together these sort of three legs of research have led to very strong evidence linking exposure to EDCs to detrimental health outcomes, including into humans,” said Gore, during a 26 Feb. online press briefing on endocrine disrupting chemicals. In fact, there is mounting evidence that suggests that EDCs contribute to disorders such as diabetes, neurological disorders, reproductive disorders, inflammation, and compromised immune functioning.
“These chemicals pose particularly serious risks to pregnant women and children. Now is the time for the UN Environment Assembly and other global policymakers to take action to address this threat to public health,” said Gore.
Pesticides and plastics, two focus areas detailed in the report, will be key agenda items at UNEA-6. Global production of plastics and pesticides is increasing even as scientists warn that chemical and plastic pollution is an escalating crisis. Plastics are made with thousands of known toxic substances, some of which are known or suspected EDCs. The report examines bisphenols and phthalates, two toxic chemical groups found in many plastics.
“I'm sure everybody has heard of bisphenol A - BPA. I would like to mention there are many other bisphenols, and BPA has been substituted by some of these other bisphenols,” said Gore. “We are exposed to bisphenol through many different routes. A major source of exposure is leaching through reusable food and beverage containers, can linings, medical and sports equipment, eye glasses, thermal paper receipts, plastic pipes, adhesives, paints and lacquers.” The second class of plastics reviewed in the report are the phthalates. Exposure occurs through PVC products, personal care products, fillers in medications and supplement, packaging for food and beverages, processing materials that are involved in making these materials, children’s toys and medical tubing for intravenous use. “So we know that plastics are EDC. There's universal acceptance about that,” Gore stated. Exposures to EDCs from plastics occur at all phases of plastics production, use, disposal, and even from recycled plastics.
Joining the briefing from Nairobi, IPEN Science Advisor and contributor to the report Sara Brosché, Ph.D., noted that plastics was currently a huge topic - and a huge problem. Fossil-based plastics production, she said, was projected to increase exponentially. During the production of plastics, chemicals are added. More plastics means therefore higher chemical production levels - and the more EDCs are produced, and the higher likelihood of even more exposure.
According to the report, while evidence of health threats from EDCs continues to mount, current regulations have not kept pace. “EDCs are different than other toxic chemicals, but most regulations fail to address these differences,” added Brosché. “For example, we know that even very low doses of endocrine disrupting chemicals can cause health problems and there may be no safe dose for exposure to EDCs. However, regulations typically do not protect against low-dose effects. We need a global approach to controlling EDCs based on the latest science with a goal of protecting the human right to a healthy environment.”
In addition to plastics and pesticides, the report also looks at EDC exposures from per- and polyfluoroalkyl substances (PFAS), man made “forever chemicals” used in hundreds of products including clothing and food packaging. Recent studies show that some PFAS can disrupt hormones such as oestrogen and testosterone and impair thyroid hormone functions. “And a big concern about PFAS is that they're very common water contaminants that are found throughout drinking water supplies in the US and can be abundant and are foodstuffs that are associated with water such as shellfish,” explained Michelle La Merrill, Ph.D., M.P.H., University of California at Davis. “The two PFAS that are most commonly studied and most importantly used to our knowledge are called PFOS and PFOA,” she added.
Not only is there some suggestion that PFAS may cause testicular and kidney cancers, there is also evidence that both substances delay puberty in rodents, particularly related to the mammary gland. PFAS have also been associated with delayed puberty in girls. The mechanism, said La Merril, seems to be their ability ‘to bind the hormone receptors and also to disrupt levels of hormones. And these hormones have included our sex hormones’.
The carcinogenicity of both was evaluated in November 2023 by the International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization. After thoroughly reviewing the extensive published literature, the Working Group classified PFOA as carcinogenic to humans (Group 1) and PFOS as possibly carcinogenic to humans (Group 2B).
The report “Endocrine Disrupting Chemicals: Threats to Human Health” is being released during the U.N. Environment Assembly (UNEA-6) meeting in Nairobi, which kicked off 26 February and continues through 1 March.