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Drinking Water Providers Seek Pause in Rush to Set MCLs for Emerging Contaminants

Siros By Steven M. Siros Free stock photo of cold, water, drink, glass

The presence of emerging contaminants such as perfluorinated chemicals (PFOS)  and 1,4-dioxane in drinking water often make the headlines as sampling technologies become more sophisticated and these contaminants are being detected with increasing frequency in drinking water systems across the country. There has been a significant push to compel regulators to set regulatory standards and/or issue health advisories for these emerging contaminants, but the impact that these standards and health advisories have on drinking water systems cannot be ignored.

In reaction to media coverage of these emerging contaminants in drinking water supplies, state regulators have been at the front of the pack in trying to set what are often conflicting standards that may not always reflect the current state of science regarding these contaminants. These state regulations often fail to consider the difficulties that drinking water suppliers face in complying with these standards, especially in instances where there are not established treatment technologies that are capable of treating these contaminants in a cost-effective manner. In addition, when setting health advisories for various contaminants, U.S. EPA typically does not consider the effect of those advisories on drinking water providers.  It is often the case, however, that these providers are pressured either by state regulators and/or the general public to ensure that the drinking water meets these health advisory levels, which are set without regard to whether cost-effective technologies exist that are capable of treating these emerging contaminants.   

These concerns were recently highlighted in comments submitted by the Association of Metropolitan Water Agencies (AMWA) in response to ongoing efforts by U.S. EPA to set standards for PFOS in drinking water. The AMWA cautioned U.S. EPA from rushing to adopt an MCL for PFOS, noting that “it is crucial that we have effective treatment technologies that are available and feasible to implement before any regulatory or non-regulatory action is taken.” The AMWA further noted that significant gaps existed with respect to the public health effects of PFOS in drinking water systems and recommended that these gaps should be remedied before regulatory standards were set by U.S. EPA. 

The AMWA and other water quality professionals support a federal standard that would apply to all drinking water systems and that appropriately takes into consideration the current state of science regarding these emerging contaminants, but also considers the technical and economic feasibility of treating these contaminants. Otherwise, there will continue to be a patchwork of regulations for these emerging contaminants, as is the case in New Jersey, where the state maximum contaminant level for PFOS has been set at 14 parts per trillion, as compared to the U.S. EPA health advisory of 70 parts per trillion. Another example of such an emerging contaminant is 1,4-dioxane, which has a U.S. EPA health advisory level of 0.35 parts per billion.  Some states have relied on that health advisory level to compel drinking water systems to treat 1,4-dioxane to below 0.35 parts per billion notwithstanding that there are not cost-effective treatment methodologies to treat 1,4-dioxane to that level.  Other states, such as Oklahoma, have no regulatory standard for 1,4-dioxane in drinking water. Until such time as the science and treatment technologies catch up with public perception, it will continue to be difficult for drinking water providers to know with certainty exactly how to deal with these emerging contaminants.