Title: Arsenic
Headings: Arsenic
Arsenic
Key facts
Sources of exposure
Drinking-water and food
Industrial processes
Tobacco
Health effects
Acute effects
Long-term effects
Magnitude of the problem
Prevention and control
WHO response

Content: Numerous studies have demonstrated negative impacts of arsenic exposure on cognitive development, intelligence, and memory (3). Magnitude of the problem
Arsenic contamination of groundwater is widespread and there are a number of regions where arsenic contamination of drinking-water is significant. It is now recognized that at least 140 million people in 50 countries have been drinking water containing arsenic at levels above the WHO provisional guideline value of 10 μg/L (4). Arsenic in Bangladesh has attracted much attention since recognition in the 1990s of its wide occurrence in well-water in that country. Since this time, significant progress has since been made and the number of people exposed to arsenic exceeding the Bangladesh drinking-water quality standard has decreased by approximately 40%. Despite these efforts, it was estimated that in 2012 about 19 million and 39 million people in Bangladesh were still exposed to arsenic concentrations above the national standard of 50 μg/L and the WHO provisional guideline value of 10 μg/L respectively (5). In a highly affected area of Bangladesh, 21.4% of all deaths in the area were attributed to arsenic levels above 10 μg/L in drinking-water (6). A similar dose-response function has been found in other parts of Bangladesh, and these results have been combined with national survey data to estimate an annual death toll of nearly 43 000 (7). The US National Research Council has noted that as many as 1 in 100 additional cancer deaths could be expected from a lifetime exposure to drinking-water containing 50 μg/L (8). The symptoms and signs caused by long-term elevated exposure to inorganic arsenic differ between individuals, population groups and geographical areas.