ABSTRACT
Arsenic (As) is a highly toxic element that has poisoned many people by being added to their food and drink, mistakenly, unknowingly, or deliberately [1]. Arsenic occurs in trace quantities in all rock, soil, water, and air [2,3]. Naturally, total As is about 1-2 mg/kg in rock, 5-10 mg/kg in soil, and 1-3 µg/L in seawater [4]. Volcanoes and microbial activities can release As into the atmosphere as arsine gas (AsH3) or methylated Arsine species. The atmospheric residence time of As species is relatively short and the As concentration is generally low (0.02 µg/m3), except in the vicinity of these sources [5]. However, anthropogenic sources such as fossil fuel combustion, mining, smelting of sulde ores, pesticide application, timber preservation, and the application of sludge and manure have elevated As levels and may cause As contamination in the food chain and drinking water [6]. As an example, past use of arsenical herbicides in sugarcane elds resulted in total As levels ranging from 50 to 950 mg/kg in some Hawaiian soils [7,8].
