Number of chemicals linked to problems such as autism DOUBLES in just seven years



Researchers warn that chemical safety checks must be tightened

Many substances are found in everyday items like food, toys and clothes

And the study warns that these findings are just the tip of the iceberg



The number of industrial chemicals known to trigger brain development problems like autism has doubled in just seven years, experts warned today.

A new study suggests toxic chemicals may be triggering increases in neurological disabilities among children, including autism, attention-deficit hyperactivity disorder and dyslexia.

The researchers warn that chemical safety checks need to be tightened up around the world to protect our vulnerable youngsters from a 'silent epidemic' of brain disorders.

A tractor sprays barley crops: Pesticides are among the toxic chemicals which may be triggering neurological disabilities among children, including autism, attention-deficit hyperactivity disorder and dyslexia

Their work also found that the list of chemicals known to damage the human brain but not regulated to safeguard children had also risen from 202 to 214.

These substances are found in everyday items including food, clothing, furniture and toys.

'The greatest concern is the large numbers of children who are affected by toxic damage to brain development in the absence of a formal diagnosis,' said Dr Philippe Grandjean, of the Harvard School of Public Health in Boston.

'They suffer reduced attention span, delayed development, and poor school performance.

'Industrial chemicals are now emerging as likely causes.'

He and his co-authors are calling for universal legal requirements forcing manufacturers to prove that all existing and new industrial chemicals are non-toxic before they reach the market place.

In the EU, the Reach (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations already impose such rules.

But without them being applied globally, the world faces a 'pandemic of neurodevelopmental toxicity', warned Dr Grandjean.

'Current chemical regulations are woefully inadequate to safeguard children whose developing brains are uniquely vulnerable to toxic chemicals in the environment,' Dr Grandjean pointed out.

Neurodevelopmental disorders such as autism, attention deficit hyperactivity disorder (ADHD), dyslexia and cerebral palsy affect one in six children worldwide.

Growing evidence strongly links these conditions to childhood exposure to hazardous chemicals such as mercury, lead, solvents and pesticides, say the scientists writing in the journal The Lancet Neurology.

'Silent epidemic': Neurodevelopmental disorders such as autism, attention deficit hyperactivity disorder (ADHD), dyslexia and cerebral palsy are thought to affect one in six children worldwide

Dr Grandjean and co-author Dr Philip Landrigan from Mount Sinai School of Medicine in New York believe this is only the tip of the iceberg.

The vast majority of the more than 80,000 industrial chemicals in widespread use in the US have never been tested for their toxic effects on the developing foetus or child, they argue.

'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', said Dr Landrigan.

'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.'

A new international prevention strategy is needed that places the burden of responsibility on chemical producers rather than governments, say the experts.

WHICH CHEMICALS POSE RISKS?

The report follows up on a similar review conducted by the researchers in 2006 that identified five industrial chemicals as 'developmental neurotoxicants' - or chemicals that can cause brain deficits.

It offers updated findings about those chemicals and adds information on six newly recognised ones.

These include manganese, fluoride, chlorpyrifos and DDT (pesticides), the solvent tetrachloroethylene, and polybrominated diphenyl ethers flame retardants. These six chemicals have been added to a list of five other neurointoxicants – lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene - first identified by the same researchers in 2006.

The study outlines possible links between these newly recognised neurotoxicants and negative health effects on children.

Manganese is associated with diminished intellectual function and impaired motor skills, while solvents are linked to hyperactivity and aggressive behaviour and certain types of pesticides may cause cognitive delays.

They conclude: 'The total number of neurotoxic substances now recognised almost certainly represents an underestimate of the true number of developmental neurotoxicants that have been released into the global environment.

'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.'

Dr Grandjean added: 'The problem is international in scope, and the solution must therefore also be international.

'We have the methods in place to test industrial chemicals for harmful effects on children's brain development

'Now is the time to make that testing mandatory.'

But Prof Andy Smith, senior scientist at the Medical Research Council Toxicology Unit in Leicester, advised caution over the U.S. study's shocking findings.

'The epidemiological studies that this review looked at have reported links between toxicity of synthetic chemicals and brain development differences.

'However, these studies mostly identify associations rather than causal relationships. As usual thousands of chemicals of "natural" source are not considered.