ALTERNATIVES TO ARSENIC-CONTAMINATED GROUNDWATER: A CASE FOR PIPED WATER IN RURAL CAMBODIA

Groundwater arsenic is a global problem that affects more than five percent of drinking water wells in the United States and many other regions of the world. In south and southeast Asia, the most common practice to deal with this contamination is to switch to a low arsenic source, often in the form of a deeper well accessing a more oxidized groundwater aquifer. Despite extensive switching, more than 100 million people continue to be exposed to excessive levels of groundwater arsenic in the region. In contrast, developed nations commonly use centralized water treatment to provide clean water. The environmental, economic, and public health impacts of these alternative water sources and treatment need to be measured to accurately determine whether such strategies could be viable in developing countries. Here, we evaluate the water quality, and comparative costs, of a variety of drinking water sources commonly used in rural Cambodia in a province where nearly 50% of groundwater resources contain elevated arsenic levels. Most drinking water sources contain fecal coliform contamination, and when stored as is common practice, this contamination equalizes water quality of different sources. As a result, all water sources need to be boiled for drinking. Groundwater, when low in As, also can contain other contaminants like manganese. The high costs of boiling water before use, compounded by water storage that does not preserve water quality, favor piped water solutions that deliver treated surface water for immediate use. Several existing private piped water supplies that deliver treated water already are being developed in these areas, including many that still lack electricity. The adoption of these systems challenges assertions about infrastructural requirements for developed world water supplies and suggests that such water supplies could be viable in other areas of the world affected by arsenic or other groundwater contamination.