Water Quality Standards; Withdrawal of Federal Nutrient Standards for the State of Arizona

EPA is taking final action to amend the Federal regulations to withdraw water quality criteria applicable to Arizona. In 1976, EPA promulgated Federal criteria for nutrients in Arizona. The Federal criteria consisted of numeric ambient water quality criteria for nutrients for eleven river segments and narrative water quality criteria for nutrients applicable to all surface waters in Arizona. Arizona has now adopted its own numeric and narrative water quality criteria for nutrients, which EPA has approved. Arizona has also established and EPA has approved implementation procedures for its narrative nutrient water quality criteria. Therefore, EPA has determined that the Federally promulgated criteria for Arizona are no longer needed and is withdrawing the Federal criteria for nutrients in Arizona.