Water Arsenic Exposure in Bangladesh Reduces Children's Intellectual Function

Joseph H. Graziano, Ph.D.
Mailman School of Public Health, Columbia University
P30ES09089 and P42ES10349

Background: Exposure to lead, mercury, and other metals has long been associated with reduced intellectual and cognitive function in children and adults. Arsenic, another metal encountered frequently in the environment usually through contaminated drinking water, is known to cause severe skin cancer and vascular breakdown especially in areas of high exposure such as Bangladesh and Chile. However, little is known about the possible cognitive effects of arsenic.

NIEHS-supported researchers at Columbia University in New York have been conducting a study on the health effects of arsenic in 12,000 adult residents of Araihazar, Bangladesh since 2000. Drinking water samples from over 6,000 wells in the region revealed that 75% exceed the WHO standard for arsenic of 10 µg/L and 53% exceed the Bangladesh standard of 50 µg/L. To investigate any possible cognitive impairment in children, these researchers conducted an investigation of intellectual function in 201 children ten years of age using a well established test modified for this population.

Advance: Exposure to arsenic in drinking water was associated with reduced intellectual function in these children. Since there is no culturally appropriate and standardized IQ test for Banglesdeshi children, the researchers were not able to make a statement about IQ points lost in relationship to arsenic; however, the observed impairment was dose-dependent in that children exposed to higher levels of arsenic had lower test scores (see Figure 1).

Figure 1. Adjusted scores by quartiles of water As for Full-Scale, Performance, and Verbal raw scores. In each case, adjustments were made for maternal education and intelligence, type of housing, child height and head circumference, and access to television.

Implications: These findings of a strong association between arsenic exposure and intelligence deficits in children add to the tragedy occurring from arsenic exposure in Bangladesh and in other parts of the world. They point out the dire need to find an effective remediation strategy to prevent arsenic exposure in parts of the world where it is endemic. The authors note that, "The global community has been slow in responding to the public health significance of arsenic exposure in Bangladesh, despite the enormous scope of the problem.” They hope "… the present findings add a new sense of urgency to efforts aimed at alleviating and eliminating” arsenic exposure in Bangladesh.

Citation: Wasserman GA, Liu X, Parvez F, Ahsan H, Factor-Litvak P, van Geen A, Slavkovich V, LoIacono NJ, Cheng Z, Hussain I, Momotaj H, Graziano JH. Water arsenic exposure and children's intellectual function in Araihazar, Bangladesh. Environ Health Perspect. 2004 Sep;112(13):1329-33.