Lead still a danger to children

Even low levels of lead in blood can adversely affect children's behaviour and educational achievement at school, new research has found.

In the study, lead levels were measured in blood samples from nearly 500 children aged between 8 months and 2 years. The results were then compared with SATS results from the same children at the age of seven.

The results showed a clear link between levels of lead in the blood and achievement in SATS exams.

Professor Alan Emond, Head of the Centre for Child and Adolescent Health at the University of Bristol, said the results demonstrated that those children with lower levels of lead in their blood were found to perform significantly better in their SATS than those with higher levels.

As a result he is calling for the World Health Organisation to halve the international acceptable level of lead in the blood.

"Exposure to lead early in childhood has effects on subsequent educational attainment, even at low blood levels (five-ten microg/dl). Our results suggest that the threshold for clinical concern should be reduced to five microg/dl,” Dr Emond said.

"We also talked to teachers as part of this research and found that children with lead levels above ten microg/dl were nearly three times as likely to show hyperactivity and anti-social behaviour," he added.

The main sources of environmental lead include water supplies (lead pipes), old lead paint and soil. Blood lead levels appear to peak between the ages of 2 and 3 – the ages when toddlers tend to put most items (including toys) in their mouths.

“While adults absorb around 10% to 15% of an ingested quantity of lead, this amount can increase to 50% in infants and young children. This lead is then absorbed into the bone where it can remain for up to 30 years,” he said.

“Lead gets incorporated into the bones and is gradually released into the blood and circulates throughout the body. It interferes with enzymes and affects many systems – including the central nervous system.”

Professor Emond recommends that to reduce lead content in the environment old pipes should be replaced as should old, flaky paint. "Any toys used in the garden, such as buggies and bikes that come into contact with soil should be washed regularly," he said.

The study is published in the online edition of the Archives of Diseases in Childhood.

This article was published on Thu 17 September 2009