A small amount of lead in the blood can also cause brain damage in children

According to Cornell University's six-year study, very small concentrations of lead in the blood, concentrations lower than current US standards, cause a decrease in children's IQ.

The study examined the level of image of direct exposure to lead to cognitive ability in children with a standard of 10 micrograms per milliliter of blood lead concentration (mcg / dl). of the National Center for Disease Prevention and Control (US), CDC. This concentration is about 100 parts per billion. The team compared children with blood lead levels of 0-5 mcg / dl for children with a blood lead level of 5-10 mcg / dl.

Richard Canfield, senior researcher at Cornell University's School of Nutrition and author of the article in the Journal of Environmental Health, said: "Whether taking into account environmental factors and the family is thought to be having an impact on a child's cognitive ability, the blood level factor still plays an important role in assessing a child's IQ ".

Galen a natural mineral of sulfide lead (Photo: iStockphoto / Sean Curry)

He added: ' We found that the average IQ of children with a blood lead level of 5-10 mcg / dl is 5 points lower than that of children with lead levels below 5 mcg / dl. This indicates that blood lead levels have a negative effect on children with much lower blood lead levels than CDC standards. This also means that we need to have stricter rules. '

In the United States in the last few months, there are about 50 types of special products including millions of toys for children that have been recovered because of the residual levels of lead in paint, plastic and metal. Mr. Canfield said: 'Our findings confirm the danger associated with exposure to low levels of lead in the toys created.'

Children in the US are mostly exposed to lead mainly from indoor dust contaminated with degraded lead-based paint. There are also toys, other harmful sources such as contaminated soil, imported food stored in lead-coated porcelain and some products made of plastic, metal and painted.

This latest discovery is based on the results of this compelling study in 2003 and was published in the New England Journal of Medicine . The convincing study results showed the negative effects of blood lead levels lower than 10 mcg / dl in a group of babies from birth to 5 years.

Todd Jusko, a candidate for a doctorate in epidemiology and co-author of both reports, said: 'These new findings are based on subsequent studies on the same group of children when they are 6 years old by conducting a comprehensive smart indicator test to determine their cognitive abilities. The study provided compelling evidence for low-grade lead exposure that also affected school-age children. '

" Poor children are the ones most affected by high blood lead levels, " said Charles Henderson, a senior researcher in human development at Cornell University. He also pointed out that, 'even a small reduction in IQ can affect scores in gifted examinations such as the SAT'.

According to the CDC, one in 50 children in the US between 1 and 5 years of age has a blood lead level higher than 10 mcg / dl and about 10% of children with a blood lead level of 5 mcg / dl or higher and about 25% of families with children under 6 years of age are at risk of lead-based paint.

According to Canfield, 'the key point is that lead is a non-biodegradable toxin that damages nerve cells and nerves leading to damage to the brain. Lead was discovered in millions of toys, even toys specially designed for children to put into their mouths that showed an unacceptable hazard. Our findings suggest that it is necessary to reassess federal standards for lead content in consumer products and the current definition of lead blood levels in children. '

This research is funded primarily by the US National Institute of Environmental Health Sciences.

Uyen Nhi