Having safe drinking water is important to all Americans. The Environmental Protection Agency's decision in the summer of 2001 to delay implementing a new, more stringent standard for the maximum allowable level for arsenic in drinking water generated a great deal of criticism and controversy. Ultimately at issue were newer data on arsenic beyond those that had been examined in a 1999 National Research Council report. EPA asked the National Research Council for an evaluation of the new data available.

The committee's analyses and conclusions are presented in Arsenic in Drinking Water: 2001 Update. New epidemiological studies are critically evaluated, as are new experimental data that provide information on how and at what level arsenic in drinking water can lead to cancer. The report's findings are consistent with those of the 1999 report that found high risks of cancer at the previous federal standard of 50 parts per billion. In fact, the new report concludes that men and women who consume water containing 3 parts per billion of arsenic daily have about a 1 in 1,000 increased risk of developing bladder or lung cancer during their lifetime.

Contents

• THE NATIONAL ACADEMIES
• SUBCOMMITTEE TO UPDATE THE 1999 ARSENIC IN DRINKING WATER REPORT
• COMMITTEE ON TOXICOLOGY
• BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY
• OTHER REPORTS OF THE BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY
• Preface
• Summary
  • CHARGE TO THE SUBCOMMITTEE
  • THE SUBCOMMITTEE'S APPROACH TO ITS CHARGE
  • THE SUBCOMMITTEE'S EVALUATION
  • OVERALL CONCLUSIONS
• 1. Introduction
  • SUMMARY OF THE NRC'S 1999 ARSENIC IN DRINKING WATER REPORT
  • POLICY BACKGROUND
  • CHARGE TO THE SUBCOMMITTEE
  • ORGANIZATION OF THIS REPORT
  • REFERENCES
• 2. Human Health Effects
  • SUMMARY OF HUMAN HEALTH EFFECTS DISCUSSED IN THE 1999 REPORT
  • RECENT STUDIES OF NONCANCER EFFECTS IN HUMANS
  • RECENT STUDIES OF CANCER EFFECTS IN HUMANS
  • LATENCY PERIOD
  • ESSENTIALITY
  • SUMMARY AND CONCLUSIONS
  • RECOMMENDATIONS
  • REFERENCES
• 3. Experimental Studies
  • SUMMARY OF EXPERIMENTAL STUDIES DISCUSSED IN THE 1999 REPORT
  • TOXICOKINETICS
  • ANIMAL TOXICITY STUDIES
  • MECHANISMS OF TOXICITY
  • SUMMARY AND CONCLUSIONS
  • RECOMMENDATIONS
  • REFERENCES
• 4. Variability and Uncertainty
  • VARIABILITY VERSUS UNCERTAINTY
  • VARIABILITY AND UNCERTAINTIES DISCUSSED IN THE 1999 REPORT
  • SOURCES OF VARIABILITY
  • SOURCES OF UNCERTAINTY
  • VALUE-OF-INFORMATION APPROACH
  • SUMMARY AND CONCLUSIONS
  • RECOMMENDATIONS
  • REFERENCES
• 5. Quantitative Assessment of Risks Using Modeling Approaches
  • OVERVIEW OF THE SCIENCE UNDERLYING EPA'S 2001 PROPOSED REGULATION
  • OVERVIEW OF THE SAB'S REPORT ON THE 2001 RISK ASSESSMENT
  • THE SUBCOMMITTEE'S EVALUATION
  • BEIR IV
  • SUMMARY AND CONCLUSIONS
  • RECOMMENDATIONS
  • REFERENCES
• 6. Hazard Assessment
  • FINDINGS OF THE SUBCOMMITTEE
  • COMPARISONS OF RESULTS OF DOSE-RESPONSE ASSESSMENTS
  • PLAUSIBILITY OF CANCER RISK ESTIMATES
  • SUMMARY AND CONCLUSIONS
  • REFERENCES

This project was supported by Cooperative Agreement No. X-82899401-0 between the National Academy of Sciences and the U.S. Environmental Protection Agency. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project.

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.