| Inorganic Arsenic: A Need and an Opportunity to Improve Risk Assessment W.R. Chappell,
1
B.D. Beck,
2
K.G. Brown,
3
R. Chaney,
4
C. Richard Cothern,
5
K.J. Irgolic,
6
D.W. North,
7,8
I. Thornton,
9
and T.A. Tsongas
10
1
University of Colorado at Denver, Denver, CO 80217 USA
2
Gradient Corporation, Cambridge, MA 02138 USA
3
Kenneth G. Brown Inc., Chapel Hill, NC 27516 USA
4
U.S. Department of Agriculture, Beltsville, MD 20705 USA
5
U.S. Environmental Protection Agency, Washington, DC 20460 USA
6
Institute for Analytical Chemistry, University of Graz, Graz, Austria
7
Decision Focus Inc., Mountain View, CA 94041 USA
8
Stanford University, Stanford, CA 94305 USA
9
Imperial College of Science, Technology and Medicine, London, England
10
Washington State University, Pullman, WA 99164 USA Abstract
This paper presents views on the current status of (inorganic) arsenic risk assessment in the United States and recommends research needed to set standards for drinking water. The opinions are those of the Arsenic Task Force of the Society for Environmental Geochemistry and Health, which has met periodically since 1991 to study issues related to arsenic risk assessment and has held workshops and international conferences on arsenic. The topic of this paper is made timely by current scientific interest in exposure to and adverse health effects of arsenic in the United States and passage of the Safe Drinking Water Act Amendment of 1996, which has provisions for a research program on arsenic and a schedule mandating the EPA to revise the maximum contaminant level of arsenic in drinking water by the year 2001. Our central premise and recommendations are straightforward: the risk of adverse health effects associated with arsenic in drinking water is unknown for low arsenic concentrations found in the United States, such as at the current interim maximum contaminant level of 50 µg/l and below. Arsenic-related research should be directed at answering that question. New epidemiological studies are needed to provide data for reliable dose-response assessments of arsenic and for skin cancer, bladder cancer, or other endpoints to be used by the EPA for regulation. Further toxicological research, along with the observational data from epidemiology, is needed to determine if the dose-response relationship at low levels is more consistent with the current assumption of low-dose linearity or the existence of a practical threshold. Other recommendations include adding foodborne arsenic to the calculation of total arsenic intake, calculation of total arsenic intake, and encouraging cooperative research within the United States and between the United States and affected countries. Key words : arsenic, cancer, dose response, drinking water, food, risk assessment. Environ Health Perspect 105:1060-1067 (1997) .
Address correspondence to B.D. Beck, Gradient Corporation, 44 Brattle Street, Cambridge, MA 02138 USA. The authors gratefully acknowledge the advice and suggestions offered by Charles O. Abernathy, Rebecca Calderon, and David Thomas of the EPA. We also acknowledge financial support and/or support-in-kind for the conferences, workshops, and task force activities from the following: Society of Environmental Geochemistry and Health, University of Colorado at Denver, EPA, Agency for Toxic Substances and Disease Registry, Health Canada, Atlantic Richfield Company, Electric Power Research Institute, International Council on Metals in the Environment, Kennecott Corporation, American Water Works Association, American Water Works Association Research Foundation, American Mining Congress, and U.S. Borax. Received 12 November 1996 ; accepted 13 June 1997.
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