110 STAT. 1628 PUBLIC LAW 104-182—AUG. 6, 1996 State and local governments, and other interested public and private entities. "(iv) PROPOSED REGULATIONS. —The Administrator shall propose a national primary drinking water regulation for arsenic not later than January 1, 2000. "(v) FINAL REGULATIONS.—Not later than January 1, 2001, after notice and opportunity for public comment, the Administrator shall promulgate a national primary drinking water regulation for arsenic. "(vi) AUTHORIZATION. —There are authorized to be appropriated $2,500,000 for each of fiscal years 1997 through 2000 for the studies required by this paragraph. "(B) SULFATE.— "(i) ADDITIONAL STUDY. —Prior to promulgating a national primary drinking water regulation for sulfate, the Administrator and the Director of the Centers for Disease Control and Prevention shall jointly conduct an additional study to establish a reliable doseresponse relationship for the adverse human health effects that may result from exposure to sulfate in drinking water, including the health effects that may be experienced by groups within the general population (including infants and travelers) that are potentially at greater risk of adverse health effects as the result of such exposure. The study shall be conducted in consultation with interested States, shall be based on the best available, peer-reviewed science and supporting studies conducted in accordance with sound and objective scientific practices, and shall be completed not later than 30 months after the date of enactment of the Safe Drinking Water Act Amendments of 1996. " (ii) DETERMINATION.— The Administrator shall include sulfate among the 5 or more contaminants for which a determination is made pursuant to paragraph (3)(B) not later than 5 years sifter the date of enactment of the Safe Drinking Water Act Amendments of 1996. "(iii) PROPOSED AND FINAL RULE. —-Notwithstanding the deadlines set forth in paragraph (2), the Administrator may, pursuant to the authorities of this subsection and after notice and opportunity for public comment, promulgate a final national primary drinking water regulation for sulfate. Any such regulation shall include requirements for public notification and options for the provision of alternative water supplies to populations at risk as a means of complying with the regulation in lieu of a best available treatment technology or other means.", (b) RADON. —Section 1412(b) (42 U.S.C. 300g-l(b)) is amended by inserting after paragraph (12) the following: "(13) RADON IN DRINKING WATER.— " (A) NATIONAL PRIMARY DRINKING WATER REGULA- TION.— Notwithstanding paragraph (2), the Administrator shall withdraw any national primary drinking water regulation for radon proposed prior to the date of enactment of this paragraph and shall propose and promulgate a regulation for radon under this section, as amended by the Safe Drinking Water Act Amendments of 1996.