Some eye-opening results have been released from a new scientific study: Researchers have discovered toxic industrial chemicals in the organs of fetuses conceived decades after many countries had banned the substances. The researchers are urging decision-makers to consider the combined impact of the mix of chemicals that accumulate in people and the environment.
“These are important findings that call for regulators to consider the collective impact of exposure to multiple chemicals rather than evaluating just one chemical at a time.”
-Richelle Duque Björvang, PhD student, the Department of Clinical Science, Intervention and Technology, Karolinska Institute
The researchers studied concentrations of 22 persistent organic pollutants (POPs)*. These are toxic chemicals that remain in the environment for long periods of time and accumulate in humans through food, drinking water and air particles. More specifically, the scientists examined samples of fetal fat tissue, liver, heart, lung and brain from 20 pregnancies that for various reasons had ended in stillbirth in the third trimester in 2015-2016.
Most current methods for estimating fetal exposure to chemicals rely on maternal blood and placenta samples as proxies. However, the new study found that, for some of the chemicals, the concentrations in the fetal tissues exceeded those found in the maternal blood and placenta. This can be explained by the fact that these chemicals tend to accumulate in fat tissue due to their structure. However, levels in fetal liver and lung also exceeded those found in the mother. Some pesticides — PeCB, -HCH, -Combined HCH and oxychlordane — were detected in fetal tissue even when they were not quantified in maternal blood samples or the placenta. According to the researchers, these latest findings suggest that blood and placenta samples may give a misleading picture on the diversity and concentration of chemicals that babies are exposed to during early development.
- The researchers identified at least 15 of the 22 POPs in every organ.
- Four chemicals were found in all tissues in all fetuses:
- HCB, a pesticide previously used to protect food crops from fungi;
- DDE, a metabolite of DDT, an insect killer used in the mid-1900s;
- Variants of PCBs, chemicals formerly used in a range of electrical products.
- PFAS: Thirteen of the pregnancies also had data from an earlier study on PFAS (chemicals used in cookware, bake ware and cooking utensils, waterproof and stain-proof products including furniture and flooring, electronics including phones and computers, firefighting foam, sporting equipment, cosmetics, moisturizers and perfume, food packaging and much more). By combining these data, the researchers were able to assess the proportion of chemicals in each type of tissue. While pesticides and PCBs were significantly over-represented in fat tissue, more than half of the chemicals in the fetal lung, brain, liver and heart was due to PFAS.
- Overall, the highest concentration of a mix of chemicals were found in fat tissue and the lowest in the brain.
- The study found that the relative exposure of baby boys was higher compared to baby girls.
*Several previous studies have linked early life exposure to POPs to adverse health outcomes such as low birth weight, gestational diabetes, ADHD, infertility, obesity and reduced sperm production.
Facts on POPs:
- Persistent organic pollutants (POPs) are toxic human-made chemicals that once released into the environment remain intact for exceptionally long periods of times and become widely distributed through air, soil and water.
- Currently, there are 30 POPs listed under the so-called Stockholm Convention on Persistent Organic Pollutants, an international environmental treaty initiated by the United Nations to eliminate or restrict the production and use of POPs. More than 150 countries have ratified the agreement.
- The list includes pesticides, industrial chemicals and by-products, many of which were long banned by countries around the world but continue to affect the environment and animal and human health.
Journal Reference: Richelle D. Björvang, Marie-Therese Vinnars, Nikos Papadogiannakis, Sebastian Gidlöf, Linn Salto Mamsen, Daniel Mucs, Hannu Kiviranta, Panu Rantakokko, Päivi Ruokojärvi, Christian H. Lindh, Claus Yding Andersen, Pauliina Damdimopoulou. Mixtures of persistent organic pollutants are found in vital organs of late gestation human fetuses. Chemosphere, 2021; 131125 DOI: 10.1016/j.chemosphere.2021.131125