These include the substance Fluazinam, which is used against fungal attacks in potato and onion plantations in Sweden. Animal studies have shown that the substance reduced the size of rat cubs' brains. It also delayed their sexual maturity.

The substance Abamectin, which is used against insect attacks in greenhouse cultivation in the EU, including cucumbers, peppers, strawberries, lettuce and herbs, also had this effect.

Obligation to communicate results

It is the manufacturers' own studies that have shown these effects. Companies are obliged to inform the European Food Safety Authority, EFSA, of the results of the studies.

But the researchers' review of the documentation shows that many companies have cheated.

The authorities were not informed

In about a quarter of the cases, pesticide companies have withheld EFSA study results.

"I think it's hair-raising. This leads to the authorities' assessments becoming unreliable and to health protection bans not being implemented," says Axel Mie, doctor of analytical chemistry at Stockholm University.

Found in playgrounds

Fluazinam is also widely used in apple cultivation in South Tyrol, where it has been found in playgrounds. Pregnant women and children in the area are exposed when the crops are sprayed and the wind spreads the substance in the valleys.

"It's upsetting, I wouldn't want to be a parent or a child in those areas," says Axel Mie.

How dangerous are these preparations for humans?

"Brain development is very similar in rats and humans. We have to assume that if a substance damages a baby rat's brain, it probably harms us too. But we can't test these substances on humans, that would be dangerous and unethical and would break the law," says Axel Mie.

The researchers have informed EFSA about the studies and an evaluation is now underway at EU level for several of the substances.