Arsenic Water

Arsenic Poison in Water:

Long-term exposure to Arsenic causes cancer of the skin, lungs, urinary bladder, and kidney, as well as skin changes such as pigmentation changes and thickening (hyperkeratosis).

Increased risks of lung and bladder cancer and of arsenic-associated skin lesions have been observed at drinking water arsenic concentrations of less than 0.05 mg/L.

This February 2000 report analyzes data collected by water systems in 25 states between 1980 and 1998 and compiled by the U.S. Environmental Protetion Agency. The study finds that millions of Americans drink tap water from systems that have been shown to contain arsenic, a known toxin and carcinogen, at average levels that pose unacceptable cancer risks. This report includes a summary of the adverse health effects of arsenic in drinking water by Dr. Paul Mushak, an eminent expert on the subject, based upon a 1999 National Academy of Sciences report. The report also contains detailed recommendations on what the EPA and water systems should do to reduce arsenic in drinking water and safeguard the health of the American public.

ARSENIC Has Been Found at Levels of Health Concern in the
Tap Water of Tens of Millions of Americans in 25 States

NRDC has obtained new data showing that tens of millions of Americans are consuming tap water every day that poses unacceptable cancer risks. This chapter summarizes these new arsenic occurrence data, while subsequent chapters discuss in detail the health implications of arsenic contamination of drinking water and the need for a stricter standard for arsenic in tap water.

The source of these new data is an EPA database not previously made public, obtained by NRDC under the Freedom of Information Act. In preparing to develop an updated standard for arsenic in drinking water, EPA asked all states for data on the occurrence of arsenic in the tap water served by public water systems. Twenty-five states responded (see Figure 1 below), providing over 100,000 arsenic test results taken from 1980 to 1998 from over 23,000 public water systems. These water systems serve a total of about 99.5 million Americans, or 40 percent of the 1990 U.S. population. Because the database does not cover states in which approximately 60 percent of the U.S. population resides, the estimates of population affected by arsenic in their tap water likely are substantial underestimates. NRDC has deleted from consideration, as potentially unreliable, samples that exceeded 1,000 parts per billion.

These new data reveal startling new details about the extent of arsenic contamination in the tap water. Table 1 shows our best estimate is that over 56 million Americans in these 25 states consumed water from systems containing arsenic at levels presenting a potentially fatal cancer risk above the level that is EPA’s highest acceptable cancer risk (1 in 10,000). Even our extremely conservative "low average" analysis approach indicates that at a minimum, over 34 million people in these 25 states drank water posing these elevated cancer risks. Our estimates are based on detailed evaluations of the EPA-collected occurrence data and the National Academy of Sciences (NAS) total cancer risk estimates.Arsenic Map Table 2 notes the total potentially fatal cancer risk that would be associated with drinking two liters of water containing arsenic at a given level for a lifetime, based upon the NAS estimates. Chapter 2 includes a further discussion of these data on risks and health effects, and how these estimates were derived.

As is clear from Tables 1 and 2, tens of millions of Americans are consuming tap water every day at levels that may pose a serious potentially fatal cancer risk and other health risks. Appendix A lists each public water system in which arsenic was found in the 25 states reporting data. The national map is intended to show the general areas that are hardest hit by the highest levels of arsenic. However, to determine whether arsenic has been found in a particular public water system, according to EPA’s database, readers should refer to the table of water systems reported in Appendix A .The map cannot be used by itself to identify whether a particular water system has an arsenic problem, because often there are several water systems located immediately adjacent to each other, and the map was generated at a scale that cannot be used to identify precisely which water system contains a given level of arsenic.