As many as one in six children could be developing neurodevelopmental disorders from exposure to industrial chemicals, according to a peer-reviewed article that appeared in the journal online yesterday.
Neurodevelopmental disorders such as autism, attention deficit disorder, mental retardation, and cerebral palsy are becoming increasingly common, although at present their causes are mostly unknown.
However, authors of the report pinpointed 202 industrial chemicals, including metals and inorganic compounds, organic solvents and pesticides, that are known to potentially harm the human brain and identified over 1000 other chemicals that are also likely to be neurotoxic in humans due to their known harmfulness in animals.
"The combined evidence suggests that neurodevelopmental disorders caused by industrial chemicals has created a silent pandemic," said the report.
The authors view the problem as "the tip of a very large iceberg" and criticise the proposed REACH (Registration, Evaluation and Authorisation of Chemicals) agreement as being inadequate for not taking neurodevelopmental disorders into account.
"Only a few substances are controlled with the purpose of protecting children," said one of the authors, Dr Philippe Grandjean from the department of environmental medicine at the University of Southern Denmark.
"The other 200 chemicals that are known to be toxic to the human brain are not regulated."
However, the European Chemical Industry Council (CEFIC) disagrees and has made a statement in reaction to the claims made in the article, along with those of the "Paris appeal" - which contains 166 recommendations for improving environmental health - that is being lobbied for today at a Unesco meeting in Paris.
Unesco is a European network representing two million doctors, including the British Medical Association, who along with many scientists and environmental activists are campaigning for a tougher version of the REACH legislation to be passed.
CEFIC's statement goes as far as to challenge those who are in support of more radical chemical regulations on their authority to comment, stating:
"It appears that among the very prestigious scientists supporting them, few are active experts in the field of the disciplines involved, such as cancer and cancer research, reproductive disorders and, in particular, human epidemiology."
"Epidemiologists have on these matters generally quite a more detailed and subtle analysis that is described in various consensus documents."
In addition, the organisation also argues that the chemicals in question are often found at levels so low that it is impossible to tell whether they pose a threat or not.
"There is no convincing evidence that exposure to environmental levels of synthetic chemicals is an important cause of cancer or that fertility is declining."
"Furthermore, a large number, if not the vast majority, of chemicals ingested by humans are of natural origin. The WHO's "Global burden of disease" shows that environmental factors have a very small contribution to disease."
The statement goes on to add:
"Assessing the independent effect of chemical exposures is particularly challenging and not conclusive because many neurodevelopmental endpoints are impacted by non-chemical factors such as genetic background, socioeconomic status, alcohol and drug abuse, and family environment."
"On the other hand, toxicological effects from exposure to many high concern chemicals are well documented; regulations (over 500) have existed for many years and the new REACH regulation will harmonise and reinforce the measures taken to evaluate the potential of danger of chemicals and more importantly, the limits acceptable to avoid any risk of adverse health effects."