On January 11, EPA released its promised guidance to utilities about monitoring for hexavalent chromium (Cr-VI) (http://water.epa.gov/drink/info/chromium/guidance.cfm). As reported in AMWA’s December 23 Special Briefing (http://tinyurl.com/12-23-SpecialBriefing), Administrator Jackson announced that the agency would take four specific steps to address Cr-VI, including issuing the guidance.
EPA is not requiring (and cannot require, per the Paperwork Reduction Act) utilities to monitor, nor is EPA requesting monitoring data. In a press release about the guidance, Administrator Jackson said that more information is needed on the presence of Cr-VI in drinking water, and for this reason the agency is providing the guidance to encourage systems to “consider how they may enhance their monitoring for chromium-VI.”
Many utilities are still deciding whether to sample. AMWA’s Regulatory Committee has discussed this issue at length and Carrie Lewis, Superintendent of Milwaukee Water Works and Committee chair has initiated a member-to-member inquiry so members can learn more about what others are planning. The inquiry is open for responses until February 11 and can be accessed online.
The Association of State Drinking Water Administrators (ASDWA) plans to work with EPA’s Office of Ground Water and Drinking Water to develop messaging related to Cr-VI sampling results that can be provided to the public. In notes to the Regulatory Committee from its January 26 conference call, AMWA provides information that three other member utilities have on their websites.
The EPA guidance provides information about the locations and frequency for collecting samples. It also provides recommendations for selecting a laboratory to measure Cr-VI and refers utilities having difficulty identifying laboratories to the state of California’s Environmental Laboratory Accreditation Program webpage to identify state certified labs. However, these laboratories are not necessarily able to detect Cr-VI at 0.02 ppb with a reporting limit of 0.06 ppb, as the guidance recommends. Following conversations with EPA and California Department of Public Health staff, AMWA recommends that utilities looking for a laboratory to sample for Cr-VI ensure that the lab is able to follow the method modifications including Application Update 144, recommended in EPA’s guidance. EPA does not plan to publish a list of capable labs for the method.
However, EPA staff has said that the agency is confident in the method detection limit and method reporting limit for the modified version of EPA method 218.6 stated in the guidance (MDL = 0.02 ppb and MRL = 0.06 ppb). This is because of the improvements specified in the modification as well as the improvements in analytic technology over the past 16 years since the method was originally developed.
The guidance does not address questions about the health significance of parts per trillion levels of Cr-VI, or about EPA’s plans and timeline for gathering the information needed to potentially revise the chromium standard. In announcing the guidance, EPA said that the MCL for total chromium assumes that the compliance sample is 100 percent chromium-6, indicating, “[t]he current chromium-6 standard has been as protective and precautionary as the science of that time allowed.”