7.2 Toxicology and Exposure
Arsenic can exist in both organic and inorganic compounds. Exposures to organic arsenic occur primarily in the food supply. Exposures through the consumption of fish (usually in the form of arsenobetaine and arsenocholine) have a relatively low level of associated toxicity (Sabbioni et al. 1991). Inorganic arsenic, however, is highly toxic and associated with risks to human health. Inorganic arsenic is ranked as the top chemical of concern on the Priority List of Hazardous Substances (ATSDR 2015). This list ranks substances that present the greatest risk to public health based on prevalence, toxicity, and potential for human exposure. Human exposure to inorganic arsenic can occur through dietary intake, which is primarily from rice consumption (Rahman and Hasegawa 2011), as well as ingestion of contaminated water or soils. Chronic exposure to arsenic has been associated with a variety of cancers (skin, lung, bladder, liver, and kidney), cardiovascular disease, and neurological impairments in exposed populations (ATSDR 2007a; Mitchell 2014).