On October 28, 2024, the Food Packaging Forum (FPF) and the Swiss Federal Institute of Technology Zürich (ETH) co-hosted the first-ever Swiss Symposium on Endocrine Disrupting Chemicals. The day was full of insightful talks about the founding of the field, the cutting edge, and a panel debating the future direction of regulation.
The foundation of EDC science
“It’s not poisoning, it’s hijacking.” So described Pete Myers, author and founder of Environmental Health News, of the actions of endocrine disrupting chemicals (EDCs) in the opening session of the Symposium. In 1991, the hazard of endocrine disruption i.e., the interference of chemicals with the hormone system resulting in changes throughout the body (“hijacking”), was only just beginning to be recognized.
The 1991 Wingspread Conference, organized by Theo Colburn (1927-2014), is largely considered to be the founding of the field of endocrine disruption. It was at that event that the term EDCs was coined. Myers was at the Wingspread as was Ana Soto who spoke later in the morning session about Switzerland’s major EDC research project NRP50.
The Swiss National Research Program NRP50 funded 30 research projects throughout the country from 2002-2007. The splashiest finding of the program was that of over 2500 young military men across Switzerland, only 38% “had sperm concentration, motility, and morphology values that met WHO semen reference criteria.” This means, over 60% had poor sperm quality and EDCs were considered the main causing factor. Though less in the public eye, the research undertaken in Switzerland as part of NRP50 led to the identification of “new chemicals as endocrine disruptors (e.g. UV filters), new targets (such as corticoid receptor signaling or PPAR), and new detection methods.” Soto shared her thought that “if you are going to err, it’s better to err on the side of caution.”
“So, the question then is, ‘are we really exposed to a variety of endocrine disrupting chemicals? Or metabolism disruptors?’ And the answer is, ‘absolutely,’” according to Jerry Heindel. While NRP50 was underway in Switzerland, elsewhere in the world researchers were establishing the links between endocrine disruptors and obesity. Heindel explained, “so, ‘endocrine disruptor’ is the general term and then if you look at chemicals that are endocrine disruptors that focus on causing obesity or diabetes, that’s a subset we call metabolism disruptors.” Heindel and Angel Nadal shared the relationship between obesity and environmental chemicals. It’s a complex topic. As Nadal described, “we are exposed to many chemicals that are affecting many pathways at the same time.”
Modern EDC research
“These chemical exposures produce externalities,” Leo Trasande, said as he brought the discussion to ongoing research. Trasande is a pediatrician whose recent work has elucidated some externalities of EDCs by quantifying their cost to American society. It runs into the millions, if not billions, of dollars in lost productivity and public healthcare costs (FPF reported, here and here). Sarah Stevens described her work investigating plastic packaging materials from multiple countries to assess if there were differences in endocrine disrupting activity based on market or polymer type. Unfortunately, she explained “we can always buy food packaging with endocrine disrupting chemicals inside” though polymer type does seem to influence the severity of the response. Products made of polyvinyl chloride (PVC) tended to have stronger effects. However, even if products of some polymer types are less prone to contain EDCs, her research showed that there is no guarantee for one polymer type coming without these chemicals. “We don’t know most of what’s in the plastics… so we don’t know what’s migrating,” Stevens explained of the plastic chemicals (FPF reported and here).
Tina Bürki-Thurnherr, from the Swiss Federal Laboratories for Materials Science and Technology (EMPA) shared insights from her work investigating the effect of micro- and nanoplastics on the functioning of the placenta. “There is a lot of crosstalk that the placenta facilitates” between mother and fetus. Bürki-Thurnherr and colleagues use various models, including tests with donated placentas, to analyze the physical movement of polystyrene particles between the mother, placenta, and fetus as well as the effects on chemical communication between mother, placenta, and fetus. As particle concentration increases on the maternal side, over time the presence of particles in the fetus increases (FPF reported).
Georg Aichinger, co-host of the Symposium and professor at ETH, started his presentation by taking a step back to describe chemical hazard, exposure, and risk and how the assessment of these factors forms the field of toxicokinetics. Aichinger shared two prongs of his work, 1) the development of new approach methodologies (NAMs) to study chemical effects without the use of animal models, “NAMs are still toddlers but rats are still rats.” And 2) how the gut microbiome can transform some ‘safe’ chemical substances into ones that have EDC properties. He shared an investigation into one such chemical found in hops. While the microbiome of the majority of people did not metabolize the chemical at significant enough levels to cause concern, it did for a small set of study participants.
Ksenia Groh & Eszter Simon from the Swiss Federal Institute of Aquatic Science and Technology (EAWAG) and Swiss Federal Office for the Environment (FOEN), respectively, were the sole representatives to shed light on the broader effects of EDCs on the environment. Groh explained, “basically, the only difference between human health-oriented versus environmentally oriented EDC assessment lies in the focus on individuals for humans and on the populations in the environment.”
Groh described the need to understand and identify EDCs in order to find ways to prevent them from being used and subsequently released into the environment via pathways like wastewater or landfills. It is potentially more efficient to avoid the use of the substances than to clean up later. Especially considering some chemicals that affect aquatic invertebrates that don’t seem to have much effect on humans. Simon discussed steps regulators in Switzerland and the EU have taken to address this issue.
Reference
Food Packaging Forum (2024). “Swiss Symposium on Endocrine Disrupting Chemicals.”
“This is a wild mess that we have released on human metabolism” – Leo Trasande
