Health risks due to radon in drinking water

Following more than a decade of scientific debate about the setting of a st andard for Rn-222 in drinking water, Congress established a timetable for t he promulgation of a standard in the 1996 Amendments to the Safe Drinking W ater Act. As a result of those Amendments, the EPA contracted with the Nati onal Academy of Sciences to undertake a risk assessment for exposure to rad on in drinking water. in addition, the resulting committee was asked to add ress several other scientific issues including the national average ambient Rn-222 concentration and the increment of Rn-222 to the indoor-air concent ration arising from the use of drinking water in a home. A new dosimetric a nalysis of the cancer risk to the stomach from ingestion was performed. The recently reported risk estimates developed by the BEIR VI Committee for in halation of radon decay products were adopted. Because the 1996 Amendments permit states to develop programs in which mitigation of air-producing heal th-risk reductions equivalent to that which would be achieved by treating t he drinking water, the scientific issues involved in such "multimedia mitig ation programs" were explored.