A new report released on September 20 by the Environmental Working Group (EWG) titled “’Erin Brockovich’ Carcinogen in Tap Water of More Than 200 Million Americans,” criticizes EPA, utilities and the chemical industry for the lack of an updated drinking water standard for chromium-6. With the release of the EWG report, AMWA members, particularly those listed in the report, should be prepared to answer public and media questions regarding chromium-6 in drinking water.
Using data compiled from EPA’s Third Unregulated Monitoring Rule (UCMR3), EWG estimates that “left untreated, chromium-6 in tap water will cause more than 12,000 excess cases of cancer by the end of the century.” The estimate is made in reference to California’s chromium-6 public health goal of 0.02 parts per billion (ppb). Large public water systems (those serving greater than 1 million people) with UCMR3 data indicating chromium-6 levels in exceedance of California’s public health goal are also listed individually in the report.
Central to the EWG report narrative is a critique of EPA’s delay in developing a chromium-6 drinking water standard. Currently, EPA does not regulate chromium-6 as an individual contaminant, instead it is regulated under the 100 ppb total chromium drinking water standard. EPA has been evaluating potential revisions to that standard, and a possible separate standard for chromium-6, for almost a decade. A risk assessment for chromium-6 under development by EPA, and which would inform the need for a regulatory revision, was originally scheduled for completion in 2011, but is now not scheduled to be released until sometime in 2017 at the earliest.
The primary reason for the delayed risk assessment release is to allow for the evaluation and peer review of a new study that suggests chromium-6 is subject to a threshold level below which damaging biological effects are not seen. This contradicts the linear cancer risk models used in the initial drafts of the risk assessment - and the final model choice used to inform the risk assessment would have a large impact on the level at which any regulation for chromium-6 is set. For its part, the EWG report attributes the delay in the EPA chromium-6 risk assessment completion and release to an “industry scheme” because the study informing the use of the threshold model was funded by the American Chemistry Council (ACC).
AMWA’s position on the question of the chromium-6 evaluation and potential regulatory revisions remains in line with its policy advocating the utilization of the best and most recent available science for all regulatory evaluations in accordance with Safe Drinking Water Act mandates. This includes support for the current delay in issuing the chromium-6 risk assessment to ensure all new information is properly vetted.