Controversial pesticides linked to declines in bee populations may harm the developing brains of unborn babies, experts at the European Food Safety Authority ruled on Tuesday. They want maximum exposure limits to the chemicals cut while more research is carried out.

 

The experts found the chemicals "may adversely affect the development of neurons and brain structures associated with functions such as learning and memory," an EFSA statement said. "Some current guidance levels for acceptable exposure may not be protective enough to safeguard against developmental neurotoxicity and should be reduced."

 

The move stems from research on rats which concluded "neonicotinoids may adversely affect human health, especially the developing brain". The newborn rats studied in the experiments found those exposed to one of the pesticides, called imidacloprid, suffered brain shrinkage, reduced activity of the nerve signals controlling movement, and weight loss. Another rat study found that exposure to the other pesticide, acetamiprid, led to reduced weight, survival and response to startling sounds.

 

EFSA said that for acetamiprid, the acceptable daily intake should be cut by two-thirds. The acute reference dose should be cut by three-quarters, EFSA said.

 

For imidacloprid, the current acceptable daily intake was judged adequate, but the other two limits should be cut by a quarter, EFSA said.

 

The two pesticides are neonicotinoids, which attack the nervous system of insects and as a class are the most widely used insecticides in the world. Both imidacloprid and acetamiprid are produced by Bayer Cropscience, whose spokesman said the reduced exposure limits were "small changes".

 

Imidacloprid was banned in the EU from many agricultural uses from 1 December, after EFSA ruled it posed an unacceptable risk to bees. Pollinators are crucial in fertilizing three-quarters of the world's food crops.