Joseph Graziano, Ph.D.

Date: September 29, 2005

Poisons in the Well: Exposure, Consequences and Remediation of Arsenic and Manganese in Bangladesh

At the time of its birth as a nation in 1971, Bangladesh had the highest rates of diarrheal disease and infant mortality in the world. Various NGOs therefore led an effort to shift the population away from the consumption of contaminated surface water via the installation of tube wells that tap groundwater, not knowing that the groundwater is naturally rich in both arsenic and manganese.

With funding primarily from the NIEHS Superfund Basic Research Program, a multi-disciplinary team of scientists from Columbia University have been conducting research that spans the disciplines of environmental health, nutritional biochemistry, epidemiology, social science, geochemistry, and hydrology. Their work, which takes place in a 25 km² area in Araihazar, Bangladesh, seeks to understand dose-response relationships between exposure and a variety of health outcomes in adults and children, while exploring factors that influence arsenic methylation and disease.

The program also seeks to understand the fundamental geochemical and hydrological processes that cause arsenic and manganese to be elevated in some aquifers, in an effort to ultimately provide safe water to the population. This seminar will give an overview of the entire Columbia University Bangladesh research program, which includes: a) a longitudinal cohort study 12,000 adults; b) cross-sectional studies of children, to test the hypothesis that arsenic and manganese may be associated with cognitive deficits; c) studies concerning the nutritional influences on arsenic metabolism and toxicity; and d) studies of the geochemistry and hydrology of the region. The seminar will also review the possible mitigation strategies for the arsenic problem, and provide evidence that the provision of arsenic-free community wells (which tap deep aquifers) is effective in reducing arsenic exposure.