US experts say chemicals may cause silent brains epidemic in young

February 16, 2014

Julia Medew

Health Editor

Leading experts are calling for a radical overhaul of regulations for chemicals to protect children from every-day toxins that may be causing a global ”silent epidemic” of brain development disorders such as autism, dyslexia and attention-deficit hyperactivity disorder.

In a review published in The Lancet Neurology on Saturday, Dr Philippe Grandjean from Harvard School of Public Health in Boston and Dr Philip Landrigan from Mount Sinai School of Medicine in New York said regulations were inadequate to safeguard foetuses and children from potentially hazardous chemicals found in the environment and everyday items such as clothing, furniture and toys.

The pair said that in the past seven years the number of recognised chemical causes of neurodevelopmental disorders doubled from six to 12. These include lead, arsenic, pesticides such as DDT, solvents, methylmercury, found in some fish, flame retardants, often added to plastics and textiles, and manganese, a commonly mined metal that can get into drinking water.

The list also controversially includes fluoride, a mineral found in water, plants and toothpaste. Many health authorities, including the World Health Organisation and Australian governments, say low levels of fluoride in drinking water are safe and protect teeth against decay.

However, Dr Grandjean and Dr Landrigan said a meta-analysis of 27 studies, mainly from China, had found children in areas with high levels of fluoride in water had significantly lower IQ scores than those living in low-level fluoride areas.

Dr Grandjean and Dr Landrigan said that since 2006, the number of chemicals that are known to damage the human brain more generally but are not regulated to protect children’s health, had increased from 202 to 214.

Of the newly identified toxins, pesticides constituted the largest group. But this could be the tip of the iceberg because the vast majority of the more than 80,000 industrial chemicals widely used in the US have never been tested for their toxic effects on developing foetuses or children.

One of the barriers was the ”huge amount of proof required” before regulation such as banning a chemical was enacted, they said.

”The only way to reduce toxic contamination is to ensure mandatory developmental neurotoxicity testing of existing and new chemicals before they come into the marketplace,” Dr Landrigan said. ”Such a precautionary approach would mean that early indications of a potentially serious toxic effect would lead to strong regulations, which could be relaxed should subsequent evidence show less harm.”

The doctors proposed a new international prevention strategy that would put the onus on chemical producers to demonstrate that their products were low risk, using a similar testing process to pharmaceuticals, and a new international regulatory agency to co-ordinate these measures.

”Our very great concern is that children worldwide are being exposed to unrecognised toxic chemicals that are silently eroding intelligence, disrupting behaviours, truncating future achievements and damaging societies, perhaps most seriously in developing countries,” they concluded in their review.

Their argument received mixed responses from Australian experts who said there were already strong programs under way to reduce exposure to substances mentioned such as lead and arsenic.

Professor Ian Rae, an expert on chemicals who advises the United Nations Environment Program, said authorities in Australia, Canada and Japan were already working on better data for chemicals introduced over time, without the kind of testing required now.

”Our National Industrial Chemical Notification and Assessment authority is prioritising the 38,000 chemicals on the Australian list and generating assessments for those of greatest concern,” he said.

Dr Oliver Jones, a lecturer in analytical chemistry in the School of Applied Sciences at RMIT University, said many of the chemicals listed in the review were already strictly controlled or banned in Australia and that where they were used, it is not ”for fun, or with malice, but to save lives”.

”DDT helps stop the spread of malaria, flame retardants reduce deaths from fires in the home and manganese is a required trace element for all living organisms,” he said.

”In addition, testing every single chemical in use for every possible effect is impossible. That said, we should never be complacent and more reasoned debate and research into best practice of the management of chemicals is very welcome.”