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Chromium-6 in Utah Drinking Water Triggers Questions, Concerns

By Ken Bousfield

Girl and mother getting water from a faucetRecent news reports about the presence of hexavalent chromium (chromium-6) in the drinking water in several northern Utah counties have raised concerns among residents about the safety of the state’s drinking water. Fortunately, the levels found in the Davis, Weber, and Box Elder County drinking-water systems are below the California state standard, the only standard for chromium-6 in the country.

The EPA will most likely develop a new standard for chromium-6. The Department of Environmental Quality’s Division of Drinking Water (DDW) is watching these developments closely and is committed to ensuring that state drinking-water standards protect Utah residents against harmful contaminants in their drinking water.

What Is Chromium-6?

Chromium is a naturally occurring element commonly found in the earth’s crust. Chromium has multiple forms, and two of its most common forms have extremely different impacts on human and environmental health.

Trivalent chromium, (chromium-3) is a nutrient essential to human health. It can be found in fruits, vegetables, grains, and meat. Hexavalent chromium (chromium-6) occurs naturally in the environment, but it is also produced through industrial processes. Chromium-6 can be released into the environment naturally through erosion or through leaching from industrial sites. Both forms of chromium are soluble in water.

How Will EPA Develop a Standard for Chromium-6?

The Safe Drinking Water Act (SDWA) requires the EPA to establish Maximum Contaminant Levels (MCLs) and Maximum Contaminant Level Goals (MCLGs) for drinking water. The MCL is the compliance standard for public water systems, and the MCLG is the level where there are no known health effects. The EPA looks at three factors when establishing standards:

  1. Is there a meaningful health benefit to regulate the contaminant?
  2. Are there technically feasible technologies to detect, reduce or remove the contaminant?
  3. How much will the treatment cost?

The MCL is a legally enforceable level that must be met by drinking-water systems. EPA tries to set the MCL as close to the MCLG as possible, but quite often the price to achieve the MCLG makes it cost prohibitive. Once the EPA determines the MCL for a particular contaminant, DDW adopts the standard and develops a corresponding state rule.

Why have Concerns about Chromium-6 Increased?

A long-term animal study by the U.S. Department of Health and Human Service’s National Toxicology Program in 2008 suggested that chromium-6 may be carcinogenic when ingested. Prior to this study, skin irritation was seen as the most common symptom of chromium-6 exposure, and inhaled hexavalent chromium was already recognized as a human carcinogen. This new information indicated that chromium-6 could also be carcinogenic at certain levels in drinking water.

The EPA responded to this new information by initiating an extensive review of the health effects from chromium-6. Under the Unregulated Contaminants Rule (UCMR), the EPA selects public water systems to test for contaminants under consideration for regulation. Since chromium-6 had not been previously tested in isolation from chromium-3, it was included on the unregulated contaminant list.

What has the EPA Review Shown?

In 2009, the agency required all large water systems in the country to test their drinking water for chromium-6. The agency also funded testing of a select few small water systems in each state. This approach ensured that the vast majority of the nation’s population had their water tested for hexavalent chromium.

The tests results from Utah’s water systems that were sampled in connection with the UCMR were tabulated along with data from all other states and reported on EPA’s web site. Test results from samples taken at northern Utah systems between 2013 and 2015 were all below 1 parts per billion, ranging from 0.06 ppb in Ogden to 0.77 ppb in Hooper.

Although EPA doesn’t currently have a standard for chromium-6, California established an MCL standard of 10 ppb and a MCLG of 0.02 ppb in 2014. All of Utah’s tests fall well below the California MCL standard of 10 ppb. It is unknown whether California’s rule setting process and standards of evaluation will be matched by EPA as they proceed with their investigation. As a result, future EPA standards (MCL and MCLG) for chromium-6 could be higher or lower than California’s standards.

What’s next for Utah?

Utah’s legislative code governs the DDW’s enforcement of the federal SDWA and doesn’t permit DDW to establish standards that are more stringent than federal standards unless there is significant evidence the federal standards are failing to protect the health of Utah residents. At this time, there is not sufficient evidence to impose a more stringent standard on public water systems in Utah. This provision prevents DDW from taking actions similar to those of California’s primacy agency.

If you are interested in finding the total chromium  and the UCMR-selected systems chromium-6 levels in your drinking water, please contact your water system and ask for a copy of the most recent Consumer Confidence Report. This report is prepared by July 1st of every year and will show the levels of all detected contaminants, along with the standards, for your water system.

Ken Bousfield Director of the Division of Drinking WaterI have worked with the Utah Division of Drinking and its predecessor agencies for nearly 40 years and have been Division Director for more than ten years. I have a bachelor’s degree in Engineering Sciences from Brigham Young University and am a registered Professional Engineer in Utah. I grew up in Los Angeles City and now live in Sandy City. My wife Gail and I celebrated our 46th wedding anniversary last month. We have four children and eight grandchildren.