the intakes of arsenic for all age groups ranged from 0.5 to 0.81 μg/ kg/day (Gunderson, 1995) and that the median intake of arsenic by adult men and by women was approximately 2.0 to 2.9 μg/day and 1.7 to 2.1 μg/day, respectively (Appendix Table E-2). Adams and coworkers (1994) reported lower intakes for adults (23 to 58 μg/day) from 1982 to 1991. There was not a marked difference in the arsenic consumption between various age groups. Gartrell and coworkers (1985) reported a similar mean U.S. intake of arsenic of 62 μg/day, and Tao and Bolger (1999) reported intakes ranging from 28 to 72 μg/day for adults from 1987 to 1988.
Data on the concentration of arsenic in human milk are limited; however, studies have reported mean concentrations ranging from 0.2 to 6 μg/kg wet weight (Byrne et al., 1983; Dang et al., 1983; Grimanis et al., 1979).
The Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals. Although members of the general population should be advised not to routinely exceed the UL, intake above the UL may be appropriate for investigation within well-controlled clinical trials. Clinical trials of doses above the UL should not be discouraged, as long as subjects participating in these trials have signed informed consent documents regarding possible toxicity and as long as these trials employ appropriate safety monitoring of trial subjects. Arsenic is currently under investigation for the treatment of leukemia (Look, 1998).
Arsenic occurs in both inorganic and organic forms, with the inorganic forms that contain trivalent arsenite (III) or pentavalent arsenate (V) being of the greatest toxicological significance (Chan and Huff, 1997). No data on the possible adverse effects of organic arsenic compounds in food were found. Because the organic forms are usually less toxic than the inorganic (ATSDR, 1998), adverse effects of inorganic forms are described. It is unclear whether risk assessments should be developed for specific groups of inorganic arsenic compounds.
The adverse effects of arsenic in humans have been identified with exposure to inorganic arsenic, although in animals higher exposures to organic arsenic produces some of the same effects as