According to a proposed rule published in the March 3 Federal Register, public water utilities would be required by EPA to monitor tap water for 28 substances, including perfluorooctanoic acid and a number of hormones, and assess for two viruses. EPA's proposed Unregulated Contaminant Monitoring Rule will target 30 contaminants—nine volatile organic compounds, seven hormones, four metals, an oxyhalide chlorate, the solvent 1,4-dioxane, six perfluorinated alkyl acids, and two categories of microbe—enterovirus and norovirus. EPA is required under the Safe Drinking Water Act to issue a new Unregulated Contaminant Monitoring Rule every five years and can specify as many as 30 contaminants for monitoring. The monitoring rule provides EPA with data to determine which drinking water contaminants occur at a frequency and concentration that would be a public concern. The proposed rule identifies six EPA-developed analytical methods and four other methods that can be used to assess 28 contaminants.
EPA did not propose monitoring for hexavalent chromium. but is seeking comment on whether it should include the chemical for monitoring for all large public water systems and for a subset of smaller systems. EPA also has asked what contaminant should be removed from the list if hexavalent chromium is added. EPA Administrator Lisa Jackson stated on February 2 that the agency is likely to regulate hexavalent chromium in tap water, but only after completing its health assessment of the substance. Currently, hexavalent chromium is monitored as part of total chromium at the 20 parts per billion level. EPA is accepting comments on the proposal until May 2. More information