Some Results of a Physiologically Based Pharmacokinetic Modeling Approach to Estimating Arsenic Body Burdens

Arsenic occurs widely in drinking-water throughout the US and most other parts of the world because of its wide distribution in the earth’s crust. In Taiwan, consumption of arsenic in drinking-water was associated with a vascular blood return defect, blackfoot disease (Astrup, 1968; Ch’i and Blackwell, 1968; Yu et al., 1984; Yu, 1984). Subsequent studies found an association between arsenic drinking-water levels and skin cancer (Tseng et al., 1968; Yeh, 1973; Bates et al., 1992; Chen et al., 1992; Smith et al., 1992) and other cancers (Tseng et al., 1968; Yeh, 1973; Bates et al., 1992; Chen et al., 1992; Smith et al., 1992). On the basis of these reports, US EPA calculated an arsenic cancer risk on the assumption that all forms of arsenic were equivalent in cancer potency and that all ingested arsenic was retained in the body over a lifetime. This approach is highly conservative, but could lead to inappropriate public policy for arsenic regulation if it were erroneous.