The detrimental health effects of environmental exposure to arsenic have become increasingly clear in the last few years. High concentrations detected in groundwater from a number of aquifers across the world, including in South and East Asia, have been found responsible for health problems ranging from skin disorders to cardiovascular disease and cancer. The problem has increased greatly in recent years with the growing use of tubewells to tap groundwater for water supply and irrigation. The water delivered by these tubewells has been found in many cases to be contaminated with higher than recommended levels of arsenic. In the study region, countries affected include Bangladesh (the worst affected), India, Myanmar, Nepal, and Pakistan (South Asia)
and Cambodia, China (including Taiwan), Lao People's Democratic Republic, and Vietnam (East Asia). This study concentrates on operational responses to arsenic contamination that may be of practical use to actors who invest in water infrastructure in the affected countries, including governments, donors, development banks, and nongovernmental organizations (NGOs).