Basic and Behavioral Science to Reduce Arsenic Exposures
Dr. Joseph Graziano and his colleagues have worked over many years to understand the dose-response relationships between exposure to arsenic and human disease. It is estimated that between 35 and 77 million people are at risk of drinking arsenic-contaminated water in Bangladesh alone (Khan et al., 1997). Over long periods of time, such consumption leads to skin lesions, cancer, and in some cases death.
Working in a 25 km2 region in Bangladesh, the Graziano team blends a spectrum of disciplines, including environmental health, geochemistry, hydrology, and social science. This interdisciplinary approach grew naturally due to a number of factors, one of which was the startling discovery that tube wells put in place in the 1970s led to unhealthy levels of arsenic in drinking water over much of Bangladesh and South Asia. With accomplishments in lead toxicology already, Dr. Graziano turned attention to the issue of arsenic and manganese in drinking water. Basic research led to discoveries about the cellular mechanisms of toxicity and interventions aimed at reducing impact of arsenic on specific subsets of individuals.
In 2000, Graziano and colleagues van Geen and Ahsan expanded their studies to try to understand more fully water usage patterns and preferences for mitigation should local wells be found to exceed accepted limits of arsenic (see Mead, 2005, for overview). With help from local villagers, handheld Global Positioning System devices were used to map the location of each well in an individual village. Later, 12,000 village residents were recruited for a study to determine arsenic levels in urine compared to that found in wells. The team determined that high-arsenic wells and low-arsenic wells could be found in the same village, and the distribution of arsenic in one village did not necessarily correlate with that in the next. This finding suggests that mitigation strategies should be tailored at the subvillage level.
More recent work has shown that, even when presented with information on the health impacts of arsenic, other factors come into play in decisions about whether to use water from high- or low-arsenic wells. Distance to the low-arsenic well appears to be one of the factors involved: if the distance is too far, some will choose to use water from the high-arsenic well over the low-arsenic well.