A recently published study reveals that pesticide companies have failed to disclose data related to brain toxicity. What does this mean for toxicity data in other fields of research?
Recently, the U.S. Geological Survey acknowledged that at least 45% of the nation’s tap water is estimated to have one or more types of the chemicals known as per- and polyfluorinated alkyl substances, or PFAS, also known as forever chemicals. This is, unfortunately, just the latest in a string of similar admissions relating to water quality which have come to light in recent years.
As more Americans grapple with the reality that we are swimming in a soup of toxins and radiation, Europeans are becoming aware of the lack of transparency involving studies of pesticides, and potentially other toxins.
A study published in early June found that some studies of pesticides relating to developmental neurotoxicity (DNT) were submitted to the U.S. Environmental Protection Agency (EPA), but not to regulatory bodies within the European Union. It took between 14 and 21 years for EU regulators to become aware of these studies. Once they were aware of the data, they enacted new safety regulations in some cases and continue to evaluate necessary steps in others.
A DNT test typically exposes pregnant female rats to a pesticide to assess their offspring for neuropathological and behavioral changes. The tests have been useful for identifying chemicals which will cause DNT in humans.
The study was first reported on by The Guardian in collaboration with European outlets Bayerischer Rundfunk/ARD, Der Spiegel in Germany, SRF in Switzerland, and Le Monde in France. It has received little attention in the American media.
In their review, “Non-disclosure of developmental neurotoxicity studies obstructs the safety assessment of pesticides in the European Unio,” the researchers write (emphasis added):
“We identified 35 DNT studies submitted to the U.S. EPA and with the corresponding EU dossiers available. Of these, 9 DNT studies (26%) were not disclosed by the pesticide company to EU authorities. For 7 of these studies, we have identified an actual or potential regulatory impact.”
The data in the 9 undisclosed studies found changes in brain size, delayed sexual maturation, and reduced weight gain in the second generation of pregnant laboratory rats exposed to a pesticide. Pesticides which were studied but not disclosed to the EU include the popular herbicide glyphosate, insecticides abamectin, ethoprophos, and pyridaben, and the fungicide fluazinam. These chemicals have been used on tomatoes, strawberries, and potatoes.
The researchers acknowledge that “apparently non-disclosure is a problem that is not rare” and, disturbingly, that there could be “no reliable safety evaluation of pesticides by EU authorities without full access to all performed toxicity studies.”
The researchers stated that the undisclosed DNT studies were produced between 2001 and 2007, but EU regulators only became aware of the studies between 2017 and 2022. The researchers found that once the EU became aware of the DNT studies some changes were implemented, including for the pesticide abamectin, where new safety levels for humans were enacted.
The studies were conducted by various pesticide companies, including Bayer and Syngenta. In the EU pesticide safety studies are commissioned and paid for by the companies seeking approval. While national regulators have the power to penalize companies who fail to disclose toxicity studies, for the moment, none have chosen to do so.
Professor Christina Rudén of Stockholm University, one of the authors of the study, believes the studies should be paid for by regulatory bodies to prevent conflicts of interest. The costs could be recovered from the companies once approved.
“There’s no reason we are aware of to believe that withholding evidence is limited to DNT studies, or limited to pesticides,” she told The Guardian. She also referenced tobacco and PFAS as examples where companies purposefully withheld knowledge about toxicity.