Arsenic concentration and speciation in infant formulas and first foods

Arsenic (As) is a ubiquitous metalloid, typically present at low concentrations in rocks, soils, and natural waters. The notable toxicity of As has led to its widespread anthropogenic use in insecticides and herbicide, first as an inorganic compound then later as the less toxic organic As compounds. Use of As in agriculture, industry, and As wastes from mining operations has led to localized areas of severe soil contamination which pose immediate human health risks from contaminated water, dust, or soil particles. More insidious, though, and affecting many millions more people, is exposure to "natural" geogenic As, resulting in both increased soluble As species in drinking water [1-3] and agricultural soils [4,5]. The detrimental health effects of As exposure via drinking water are well accepted and have led to a lowering of environmental regulatory limits to 0.01 mg [l.sup.-1] promoted by both the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) [6]. The exposure of millions of people to elevated levels of geogenic As in drinking water is happening now in the Asian subcontinent, particularly in Bangladesh but also in India, Vietnam, and Cambodia [7]. Indeed, anywhere where access to drinking water is via groundwater wells there is the potential for elevated As depending on the prevailing geology and subsurface biogeochemical conditions.