Arsenic Risk Assessment
Inorganic arsenic (iAs) is a naturally occurring metalloid found in soil, bedrock, and water. Individuals worldwide are unknowingly exposed to arsenic through ingestion of contaminated groundwater and food. Water contamination from arsenic comes from two major sources. First is from arsenic present in geological formations leaching into groundwater supplies through natural ecological processes. The second is from anthropogenic activities, namely mining and purification of precious metals. Arsenic affects multiple biological systems and causes cancers of the skin, lung, bladder, as well as other tissues. Arsenic is also associated with noncancer health effects such as skin lesions, cardiovascular disease, diabetes, pulmonary effects, neurological effects developmental, and reproductive toxic effects. Inorganic arsenic is metabolized into pentavalent and trivalent mono- and dimethylated arsenic species before excretion in urine. The trivalent mono- and dimethylated arsenicals produced during metabolism have been shown to be toxic than their parent compound and pentavalent forms of arsenic. This chapter summarizes risk assessment conclusions for inorganic arsenic and its related compounds from state, federal, and international health agencies.