The chlorpyrifos pesticide was approved, although it harms the brain. The manufacturer has misleading information about the danger, researchers said.
Scientists are making serious allegations against the chemical company Dow Chemical/Corteva and pesticide approval authorities: “The manufacturer of the insecticide chlorpyrifos misleadingly presented the results of an animal experiment in 1998, and the authorities did not correct it until 2019,” said chemist Axel Mie von the Swedish Medical University Karolinska Institute. “The summary of the results concealed that the young rats’ cerebellums were smaller, even if their mothers were exposed to only very small amounts of chlorpyrifos during pregnancy,” added Christina Rudén, ecotoxicology professor at Stockholm University.
That is why the European Union re-approved the agent, which had been allowed for decades, in 2005, although the data indicated possible damage to the brains of human embryos. The researchers are now calling on the EU to investigate indications of possible manipulations.
The EU banned the substance in early 2020. Because researchers around Mie had evaluated the raw data from the rat experiment and referred to the incorrect evaluation in a specialist article in 2018. In addition, three studies in particular from 2005 to 2016 showed cognitive and behavioral deficits in children who were exposed to pesticides from the group of organophosphates such as chlorpyrifos in the womb. Also, new studies could not rule out that the pesticide damages the genome.
However, the EU-wide ban only came 22 years after the rat study provided evidence of the danger. Chlorpyrifos has not been allowed to be injected in Germany since 2015 – unlike in Spain and Poland. But according to the Federal Office of Consumer Protection, for example, in 2018 the pesticide was found in 23 percent of the grapefruits examined, 21 percent of the bananas analyzed and 20 percent of the orange samples. According to the EU Food Safety Authority, chlorpyrifos was one of the most common pesticides found in food in 2018. “Studies indicate a lower intelligence quotient in children due to chlorpyrifosexual exposure,” write Mie and Rudén. “In view of what is at stake, the EU Commission would have to investigate how the apparently incorrect analysis by the company could have come about.”
According to the scientists, it is also necessary to investigate why the offices are not correcting the errors. Spain started testing chlorpyrifos on behalf of the EU in 1999. As always with such procedures in Europe, the US or Canada, the Spanish government experts mainly based on studies that the pesticide manufacturers had commissioned and summarized for the authorities. Polish offices helped the Spaniards. Her judgment was checked by, among other things, German officials. However, the experts did not point out the dangers to embryos in the official report on the risks of the pesticide.
Apparently, the authorities only relied on the summary of Dow Chemical in the study with the rats. The woman never mentioned that the rats’ fleshes were flatter, even if their mothers were only given small dose of chlorpyrifo during pregnancy. On the other hand, this could very well be read from a table in the data section of the study. “However, the troubling finds are hidden in an average number for all brain regions, which at first glance was unremarkable,” said Mie. “If you stand in a bucket of boiling water with one foot and in a bucket with ice cubes with your other foot and says that on average the water temperature is quite pleasant: then that’s a correct statement, but it’s only half the story Truth.
Both sloppiness and deliberate manipulation are conceivable. The latter is supported by the fact that the authors did not conceal other data in an average value, but evaluated it correctly. “If the company had correctly evaluated the data, chlorpyrifos would have been banned 20 years ago,” said Rudén. However, despite the many experts from the authorities, the error in the evaluation of the test data by the authorities remained undetected. They did not act even when in 2000 the US Environmental Protection Agency (EPA) criticized the data analysis on brain structure in the study as “unsuitable and not conclusive”.
Dow scientists defended the study in 2019, arguing that certain rat cubs’ cerebellas were smaller because the brains shrank when stored in a fixative solution prior to testing. However, according to Mie, the study clearly stated that all brains of the age group in question had been examined at the same time.