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Environmental Problems and the Socially Vulnerable: An Environmental Anthropological Approach to Research on Arsenic Contamination of Groundwater

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Environmental Problems and the Socially Vulnerable: An Environmental Anthropological Approach to Research on Arsenic Contamination of Groundwater

Department of Environmental Design, Faculty of Design
Environmental Design Global Hub
Professor Masakazu Tani

　My lab conducts research on the social causes and effects of environmental problems, primarily in developing countries. In particular, our research focuses on the relationship between environmental problems and socially vulnerable groups such as the poor.
　One of these studies investigates arsenic contamination of groundwater. Arsenic contamination is a global problem, but has especially been found throughout the large river basins of Asia. Based on the areal extent and number of people affected, the arsenic contamination of the groundwater along the Ganges River, running through India, Nepal, and Bangladesh, is sometime called the worst environmental contamination in the world. The contamination is caused by the liquefaction of natural-occurring arsenic in groundwater. People drink water from arsenic-contaminated wells, leading to chronic arsenic poisoning.

The worst environmental contamination on earth: Areas of arsenic-contaminated groundwater of the Ganges River that runs through Nepal, India, and Bangladesh.

　Since the degree of groundwater contamination in a given location is determined by various conditions in the ground, there should be no relation between the economic situation of the people above ground and whether or not the water they happen to drink is contaminated with arsenic; therefore, any negative health effects that do appear should affect the residents randomly. However, surveys in rural communities in Bangladesh and Nepal have shown that the populations most affected are the poor and the low-caste.

 

 A girl drawing water from a tube well in a rural community in Nepal. Tube wells, wherein water is drawn up through a pipe pounded into an aquifer, comprise over 90% of water sources in rural South Asia. If these aquifers are contaminated with arsenic, the residents’ health is affected.

　Reasons for this phenomenon are not entirely clear, but one factor appears to be general physical health due to differences in diet such as the consumption of animal-based protein. However, this alone cannot explain the high rate at which the lowest castes in Nepal are affected. The socially disadvantaged position in which these populations are placed, such as through the limitation of their rights, likely bears some relation, but we still cannot explain the precise mechanism by which this operates. Since it is difficult to explain this type of relationship between cultural customs and the health of its members by means of reductionist approaches, we are searching for a new approach.

The two paths by which arsenic from groundwater enters the human body. The most serious path is through drinking water (right); by drinking the water drawn up from wells, arsenic is directly ingested into the body. In the route shown on the left, arsenic contained in irrigation water for crops such as rice is absorbed by the plants, and then a portion of this is ingested by humans as food.

A dug well equipped with a filtration tank to provide safe drinking water free of arsenic. A sand filtration tank deposits the arsenic at the bottom, bringing the concentration to safe levels and thereby producing drinking water.

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Department of Environmental Design,Fuculty of Design
Professor Masakazu Tani