RESUMO
After almost 20 years of experience with implementing the Safe Drinking Water Act and eight with Amendments to the Act, the individual states within the United States have gained valuable experience while trying to reconcile the legal mandates provided by the statutes with the science underlying them. This paper presents four different topics illustrating the problems of reconciling these two issues in the regulation of toxic chemicals in drinking waters. It presents these from the perspectives of the states of Massachusetts, Rhode Island, Connecticut, and New Jersey and offers suggestions for improved program efficiency based on considerations of comparative human health risks. The approach and schedule for controlling toxic chemicals used through 1994 are first examined and a recommendation is made for more flexibility in the rate at which chemicals are regulated. Recent U.S. EPA proposals to more stringently control radon in drinking waters are presented in the context of all sources of radon exposures, illustrating the intersection of science, laws, and economic consequences of regulatory initiatives. Inhalation and dermal exposures as a result of using chemically contaminated drinking waters are then discussed with the suggestion of the possible underprotectiveness of some present standards. Finally, the difficulty faced by the states and federal government in the control of naturally occurring arsenic exposures through drinking water is also presented and an argument is made for more local flexibility in the application of health-based standards.