Pollution 'putting millions of children at brain damage risk'; Factbox

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David Rose
08 November 2006
The Times

(c) 2006 Times Newspapers Limited. All rights reserved

Millions of children throughout the world may have suffered brain damage as a result of industrial pollution, researchers say.

Common pollutants may be causing a "silent pandemic" of neurodevelopmental disorders by impairing the brain development of foetuses and infants, scientists writing today in The Lancet medical journal say.

Potential effects of exposure to even tiny amounts of toxic chemicals include lower IQ scores and conditions such as autism, attention deficit disorder, and cerebral palsy.

One in six children is thought to have some kind of developmental disability, but the exact causes are largely unknown.

The American and Danish researchers say that lead, methylmercury, arsenic and solvents such as ethanol and toluene are among 202 industrial and agricultural chemicals with potential to damage the brain. But these are likely to be the "tip of a very large iceberg" of potentially noxious chemicals, they write.

More than 1,000 chemicals are known to be neurotoxic in animals, and are also likely to be harmful to humans, especially during the vulnerable phases of development that begin during pregnancy and can extend as late as the onset of adolesence.

Other substances that could prove to be toxic in excessive amounts include fluoride, a common additive in drinking water and toothpaste, the researchers say.

In the EU, 100,000 chemicals were registered for commercial use in 1981, and in the US, 80,000 are registered.Yet fewer than half have been subjected to even token laboratory testing, the researchers say, and in 80 per cent of cases there was no information about the danger to children.

Although new chemicals are more rigorously tested, access to data could be restricted for commercial reasons.

The researchers are calling for much tighter worldwide controls on chemicals, and a "precautionary approach" to testing. In the EU, a new testing programme called Reach is planned that will enforce tighter controls. But the scientists say that this does not go far enough, since it fails to emphasise the importance of testing chemicals for damage that they may cause to the developing brain.

Philippe Grandjean, from the University of Southern Denmark in Winslowparken, who co-wrote the study said: "Only a few substances, such as lead and mercury, are controlled with the purpose of protecting children.

"The 200 other chemicals that are known to be toxic to the human brain are not regulated to prevent adverse effects on the foetus or a small child."

Dr Grandjean and his co-author, Philip Landrigan, from the Mount Sinai School of Medicine in New York, trawled a range of scientific data sources to compile their evidence. Five substances for which sufficient toxicity evidence exist were examined in detail -lead, methylmercury, arsenic, polychlorinated biphenyls (PCBs) and toluene.

For example, virtually all children born in industrialised countries between 1960 and 1980 must have been exposed to lead from petrol, the researchers say. Based on what is known about lead's toxic effects, this may have reduced the number of people with IQ scores of 130 and above by more than half, and increased the number of those with scores of less than 70.

Other results of lead exposure included shortened attention span, slowed motor co-ordination and heightened aggressiveness. In later life, early damage from lead can increase the risk of Parkinson's and other neurodegenerative diseases.

Pinning down the effects of industrial chemical pollution is extremely difficult because they may not produce symptoms for several years or even decades, the scientists say.

Writing in the online version of The Lancet, the scientists conclude: "The combined evidence suggests that neurodevelopmental disorders caused by industrial chemicals has created a silent pandemic in modern society."

HOW THE YOUNG ARE BEING POISONED

LEAD

Toxic effects recognised since Roman times, but the use of lead in petrol, paints, ceramic glazes and other products continued unchecked. Children exposed to even small amounts can suffer problems with concentration, memory, cognition and behaviour

METHYLMERCURY

Has been found in waters next to plastics factories, hospitals and incinerators and can contaminate freshwater fish and seafood. Studies in New Zealand and the Faroe Islands have noted a three-point decrease in the average IQ of children born to women who had eaten contaminated seafood, as well as other memory, attention and language impairments

ARSENIC

A notorious poison that is present in groundwater worldwide and widespread industrial pollution. Studies of school-age children show cognitive deficits and declines in IQ associated with drinking contaminated water Napoleon, left, who may have died of arsenic poisoning

POLYCHLORINATED BIPHENYLS (PCBs)

Widely used in electrical equipment as insulators and elsewhere in industry. Contaminated products can include cooking oil and dairy products, and exposure is associated with acne-like skin conditions in adults, low birthweight in babies and slow and clumsy childhood development

SOLVENTS

Include ethanol, turpentine and toluene, and are commonly used in dry cleaning, paint thinners, glue, detergents and in perfumes. Effects, as with heavy alcohol exposure, on developing foetuses can lead to decreased IQ scores and delayed development of speech and motor function

PESTICIDES

More than 600 pesticides are registered, inlcuding those that act against insects, rodents, fungi and weeds. Children exposed directly to high levels of the chemicals have been shown to have diminshed shortterm memory, hand-eye co-ordination, reaction times and drawing ability, compared with unexposed children

(c) Times Newspapers Ltd, 2006

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