MILLIONS of children across the world may have been mentally impaired after being exposed to low levels of mercury in their mothers' wombs. Philippe Grandjean of Odense University in Denmark and his team measured mercury levels both in the umbilical cord blood of more than 900 babies and in their mothers' hair in the Faeroe Islands. The children were then given 20 psychological tests at the age of six or seven. The study found children of pregnant women with mercury levels well below WHO safety limits had deficits in learning, attention, memory and other skills. "The more mercury the children had, the more poorly they performed," says Grandjean.
The mercury came from eating pilot whales. But fish-eaters across the world are at greater risk. For, bacteria convert mercury deposited in the ocean into methyl mercury, which is more readily taken up by fish.
The new study will boost efforts the world over to cut mercury emissions which come mainly from coal-burning power plants and waste incinerators. The US Environment Protection Agency recommends a maximum daily dose of 0.1 micrograms/kg of body weight but says thousands of women of child-bearing age are exposed to higher doses. Ironically, however, moves to reduce mercury emissions in the US are being resisted by the Food and Drug Administration which is earnestly trying to persuade people to eat more fish.
