MISSION: Southwest Research and Information Center is a multi-cultural organization working to promote the health of people and communities, protect natural resources, ensure citizen participation, and secure environmental and social justice now and for future generations

Changes in Standards for Uranium in Drinking Water Driven by New Studies

Uranium has long been known to damage the kidneys of laboratory animals and uranium-fuel cycle workers, especially in high doses through eating contaminated water or foods (i.e., ingestion) or through breathing contaminated air (i.e., inhalation). But recent studies of Canadian populations exposed to moderate levels of uranium in their drinking water demonstrate that uranium is more toxic to the human kidney than previously thought.

As a result of these studies, regulatory agencies and professional advisory groups are recommending a change to the maximum acceptable levels of uranium in drinking water. For example, Health Canada in 1999 recommended a maximum acceptable concentration of uranium in drinking water of 0.01 milligrams per liter (mg/l), and since then has recommend that the provincial governments adopt regulations limiting uranium levels to 0.02 mg/l in public water supplies. Similarly, the U.S. Environmental Protection Agency (EPA) is expected to issue a final uranium limit of 0.03 mg/l) for public water supplies regulated under the federal Safe Drinking Water Act.

SRIC staff is contributing locally to this national and international effort to redefine the chemical toxicity of uranium. Over the past year, the staff, working with physicians at the Indian Health Service's Crownpoint Healthcare Facility in Crownpoint, N.M., and with toxicologists at UNM's Center for Population Health in Albuquerque, has conducted an extensive review of the world's scientific literature on uranium's biological effects, and summarized that review in a series of white papers and data spreadsheets.

This work is supporting two important objectives:

• First, those of several Navajo communities and institutions that are interested in improving and expanding water quality and health surveillance in a population already affected by a high rate of kidney disease.
• Second, those of the New Mexico Environment Department whose officials now question the safety of the state's current groundwater protection standard for uranium of 5.0 mg/l.

In the coming year, this work will contribute to the design of a study that assesses the effects of chronic ingestion of uranium in drinking water on kidney health in certain Navajo communities, and to the likely downward revision of the state's groundwater protection standard for uranium. Both initiatives will contribute to improving public health while also addressing important community needs.