Exposure to arsenic significantly reduces intellectual function

Aug 11 2004

A recent study of children exposed to arsenic-tainted water in Araihazar, Bangladesh found that water arsenic was significantly associated with reduced intellectual function.

Naturally occurring arsenic in tube well water has led to the exposure of millions of people in South Asia, and Bangladesh in particular. The new study is the first systematic look at the effects of this toxic element on children's intellectual abilities.

Carried out in 201 ten year-old children of parents participating in an on-going study examining health effects of arsenic exposure, this most recent endeavor is the result of active collaboration among the New York State Psychiatric Institute, Columbia University's Mailman School of Public Health, and Lamont-Doherty Earth Observatory, Columbia University, and researchers in Bangladesh.

The children in the study were assessed using the WISC III, a battery of tests adapted by Dr. Gail Wasserman, a child psychologist at Psychiatric Institute, in order to make them more culturally relevant. The tests evaluate intellectual abilities such as comprehension and problem-solving.

After adjusting for sociodemographic covariates such as parents' education, occupation and housing type, as well as water manganese content (also elevated in many Bangladesh wells), the researchers determined that the widespread use of water contaminated by arsenic had a deleterious effect.

"We believe that our finding is both important and tragic and adds urgency to the need for effective remediation in Bangladesh and other regions of south Asia where consumption of arsenic contaminated water is prevalent," wrote the authors.

Joseph Graziano, PhD, professor of environmental health sciences and associate dean for research at the Mailman School, added, "A staggering number of people are affected. While we do not know if a reduction in exposure would be associated with improved functioning in children already exposed, a better understanding of the relationship could be obtained by tracking exposures and outcomes regularly. We are working closely with our Bangladeshi colleagues to curb the exposure to arsenic. The findings are also highly relevant in the U.S., where water arsenic concentrations sometimes exceed the WHO standard of 10 ug/L "

According to the researchers, approximately 30-40 million Bangladeshis have been exposed to contaminated water supplied by approximately 10 million tube wells. Since arriving in 2000, the investigators have seen to the installation of low-arsenic private and community wells in their 10 square mile study region, and implemented a village education program to reduce exposure. New support from Columbia's Earth Institute will allow the investigators to expand their remediation efforts.