EPA held a stakeholder meeting on June 16 in Washington, DC to present preliminary information about its possible regulatory determinations (Reg-Det 3) from the third Contaminant Candidate List (CCL). As expected, EPA is considering nitrosamines as a frontrunner for potential regulation. Nitrosamines were previously identified under the drinking water strategy as a potential group for regulation.
Regarding nitrosamines, EPA noted that its health reference levels were adjusted from the IRIS cancer slope factor based on the 2005 agency document, Cancer Guidelines and Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens, which recommends that the agency apply age dependent adjustment factors to determine the unit risk for early life exposures to mutagenic carcinogens.
Also on EPA’s short list is MTBE, which was monitored under the first Unregulated Contaminant Monitoring Rule (UCMR). Several other potential contaminants under consideration for a regulatory determination include: the pesticides acetochlor, alachlor and metolachlor and its ESA and OA degradates, and the explosives RDX and 1,3-dinitrobenzene. These were monitored under UCMR 2. EPA also indicated it is considering molybdenum, strontium, vanadium, PFOS and PFOA among others. These five contaminants were proposed for UCMR-3 monitoring. EPA plans to publish preliminary determinations for comment in late 2012 and final determinations in 2013. Proposed regulations from Reg-Det 3 would be expected in 2015.