Low IQ of Thai children
A report last week attributed the low average IQ of Thai children in part to their family situation. There is another factor which is likely to contribute to low IQ - lead poisoning.
Research in 2013 found that 80 per cent of enamel paints produced in Thailand had lead levels in excess of the suggested safe level of 90 parts per million. Some paints had more than 1,000 times the limit. Lead is a neurotoxicant that is particularly harmful to the developing brain, and exposure results in decreased IQ, attention deficit disorder, aggressiveness and behavioural problems.
The current limit for blood lead in Thai children is 10 micrograms per decilitre. In 2013, the US lowered the limit from 10 to 5mcg/dl after research showed that children with lifetime average concentrations between 5 and 9.9mcg/dL scored 4.9 points lower on Full-Scale IQ than those with a level of less than 5. An unpublished study by Dr Adisak Plitponkarnpim found that 13 per cent of children tested in Rayong, Samut Prakan and Chachoengsao had lead levels in excess of 10mcg/dl. This lead exposure could well explain why Thai children’s average IQ is only 93.1.
Thai children’s exposure to lead must be lowered to enable their brains to develop properly and attain a normal IQ. The first step to achieve this is for the government to make the limit of 90ppm for lead in paint mandatory, not a suggestion as is currently the case. We cannot expect large corporations whose first consideration is profit to care about the welfare of our children.
In December 2014 I contacted one of Thailand’s largest paint manufacturers to ask what they planned to do about the high levels of lead in some of their paints. They replied that there was no excess in any of their products. In fact, a number of their paints marketed as “mercury- and lead-free” actually contained several hundred times the limit for lead. After I sent them a copy of the 2013 report, they thanked me and said their director of research and development would contact me. Four months later I have not heard from him.
Meanwhile, if parents are concerned about the effect of lead in paints on their child’s IQ, they can download the article with the list of paints and their lead levels from http://tinyurl.com/qd3rk4y.
David Hammond
Author of “Mercury Poisoning: The Undiagnosed Epidemic”
