Human Health Criteria - Science Advisory Board: Toxicological Review of Inorganic Arsenic
About the Science Advisory Board (SAB) Arsenic Review Panel (meeting September 12-13, 2005)
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On July 24, 2005, EPA asked the SAB to review two draft documents assessing the cancer risks associated with oral exposure to arsenic. People can be exposed to both natural and man-made arsenic and arsenic-containing compounds through drinking water, food, soil and air. Oral exposure to inorganic arsenic is known to cause cancer of the skin, lung, and bladder in humans. Arsenic comes in both organic and inorganic forms. This review is only of inorganic arsenic; EPA's pesticides program is investigating organic arsenic.
We are updating the risk assessment used to revise the drinking water standard in 2001. The Agency committed to work with the National Academy of Sciences (NAS) and the National Drinking Water Advisory Council to reassess the scientific and cost issues associated with the January 22, 2001, Final Rule for Arsenic in Drinking Water. This revision reflects recommendations made by the NAS and new information.
We sought comments and advice from the SAB on key science issues concerning:
- how the human body treats and responds to different forms of arsenic,
- how arsenic causes cancer and resulting implications for dose calculations,
- appropriateness of the types of data used in the risk assessments, and
- approaches for evaluating cancer risks at low doses.
Toxicological Review of Ingested Inorganic Arsenic (PDF) (114 pages, 6.8MB)
These Microsoft Excel spreadsheets reflect the approach taken to re-implement the recommendations for calculation of cancer risk from inorganic arsenic. They are provided to permit the reader to better understand the Inorganic Arsenic risk calculations and to facilitate discussion.
Issue Paper: Inorganic Arsenic Cancer Slope Factor (PDF) (38 pages, 265 K)
Since publication of the 2001 NAS report, our Arsenic Cancer Slope Factor Workgroup was organized to examine the recommendations and their potential influence on regulation of inorganic arsenic by the various program offices.
We provide citations for some reference materials below. Please note that the draft Toxicological Profile and the July 22, 2005, draft final Issue Paper: Inorganic Arsenic Cancer Slope Factor do not represent final Agency policy or decisions.
- Alam MGM, ET Snow, A Tanaka. 2003. Arsenic and heavy metal contamination of vegetables grown in Samta village, Bangladesh. The Science of Total Environment 308: 83-96.
- Bates MN, OA Rey, ML Biggs, C Hopenhayn, LE Moore, D Kalman, C Steinmaus and AH Smith. 2004. Case-control study of bladder cancer and exposure to arsenic in Argentina. Am. J. Epidemiol. 159:381-389.
- Chiou, HY, Hsueh, YM, Hsieh, LL, et al. (1997) Arsenic methylation capacity, body retention, and null genotypes of glutathione S-transferase M1 and T1 among current arsenic-exposed residents in Taiwan. Mutat. Res. 386:197-207.
- Drobná, Z, Waters, SB, Walton, FS, et al. (2004) Interindividual variation in the metabolism of arsenic in cultured primary human hepatocytes. Toxicol. Appl. Pharm. 201(2):166-177.
- Duxbury JM, AB Mayer, JG Lauren, N Hassan. 2003. Food chain aspects of arsenic contamination in Bangladesh: Effects on quality and productivity of rice. Journal of Environmental Science and Health, Vol. A38, No. 1, pp.61-69.
- Lamm SH, A Engle, MB Kruse, M Feinleib, DM Byrd, S Lai, R Wilson. 2004. Arsenic in drinking water and bladder cancer mortality in the United States: An analysis based on 133 U.S. counties and 30 years of observation. J Occup Environ Med 46(3):298-306.
- Lamm SH, DM Byrd, MB Kruse, M Feinleib, S-H Lai. 2003. Bladder cancer and arsenic exposure: Differences in the two populations enrolled in a study in southwest Taiwan. Biomedical and Environmental Sciences 16:355-368.
- Roychowdhury T, T Uchino, H Tokunaga, M Ando. 2002. Survey of arsenic in food composites from an arsenic-affected area of West Bengal, India. Food and Chemical Toxicology 40:1611-1621.
- Steinmaus, C, Yuan, Y, Bates, MN, and Smith AH. 2003. Case-control study of bladder cancer and drinking water arsenic in the western United States. American Journal of Epidemiology 158(12):1193-1201.
- Watanabe C, A Kawata, N Sudo, M Sekiyama, T Inaoka, M Bae, R Ohtsuka 2004. Water intake in an Asian population living in arsenic-contaminated area. Toxicology and Applied Pharmacology 198:272-282.
- Zhang T-C, MT Schmitt, JL Mumford. 2003. Effects of arsenic on telomerase and telomeres in relation to cell proliferation and apoptosis in human keratinocytes and leukemia cells in vitro. Carcinogenesis 24:1811-1817.