In response to recent nationwide questions regarding the presence of hexavalent chromium (chromium-6) in drinking water, Medford Water Commission (MWC) has initiated enhanced, trace level monitoring for chromium within our water system. The Environmental Protection Agency (EPA) has recommended that water suppliers perform this testing to determine what levels may be present in drinking water.
Within existing drinking water regulations, all forms of chromium are regulated collectively under the “total chromium” standard, which allows a maximum concentration of 100 parts per billion (ppb) in drinking water. EPA is currently working to complete a scientific review and risk assessment for chromium-6 to determine if a new drinking water standard should be established.
MWC has tested for total chromium since the early 1980s with all results reported below 1 ppb (less than one one-hundredth of the existing standard). No prior testing specific to chromium-6 has been conducted. Testing for total chromium and chromium-6 was recently performed on both the Big Butte Springs and Rogue River water sources and selected points in the water distribution system.
Chromium-6 levels measured in the Medford water system averaged 0.160 ppb, and ranged from 0.103 ppb to 0.190 ppb. These results are comparable with levels found in other cities throughout Oregon and the U.S.
It is important to note that the finding of trace amounts of chromium-6 in the drinking water should not be cause for alarm. Advances in analytical science have made it possible to quantify extremely low amounts of substances in water, and such detection does not necessarily imply health risk. The presence of chromium-6 in the Medford water sources occurs naturally and is not the result of high-level industrial contamination that brought this issue to national attention. Consumers should also recognize that trace-level concentrations of chromium-6 are known to occur in bottled water, tea, and soft drinks.
MWC reminds our customers that our water easily exceeds all current water quality standards, and we continue to support the efforts of EPA to complete scientifically sound risk assessments and regulatory reviews in a timely manner. MWC is committed to providing a safe, healthful water supply for the community.
MWC Fact Sheet:
Hexavalent Chromium (chromium-6) in Drinking Water
What is it?
Chromium is the 21st most abundant element found in the earth’s crust. It is odorless and tasteless and is found naturally in rocks, plants, soil and volcanic dust, humans and animals. Trace amounts of total chromium and chromium-6 are found in water throughout the world, including the rivers and streams flowing from the Cascade Mountains. The most common forms of chromium in the environment are trivalent (chromium-3), hexavalent (chromium-6) and the metal form, chromium-0. Chromium-3 occurs naturally in many vegetables, fruits, meats, grains and yeast, and is an essential component required to metabolize sugars and lipids in our bodies. Chromium-6 and -0 are naturally occurring in water, but are also found as a result of industrial processes.
Is chromium-6 regulated?
The current maximum contaminant level for chromium in all forms, including chromium-6, is 100 parts per billion (ppb). New health effects information has become available since the original standard was set, so EPA is currently re-evaluating the chromium standard based on new science. When the scientific assessment is finalized, EPA will determine if a new standard should be established.
Is chromium-6 a carcinogen?
In a draft human health assessment for chromium-6 that was released in September 2010, EPA proposed classifying chromium-6 as likely to cause cancer in humans when ingested over a lifetime. A safe exposure level is the primary focus of current studies. EPA is expected make a final determination by the end of 2011.
Is the tap water safe to drink?
Yes. The finding of trace amounts of chromium-6 in the drinking water should not be cause for alarm. Our source water quality has not changed and the tap water remains in full compliance with all drinking water standards. Ensuring a safe public water supply is our top priority. MWC will be closely following the science and regulatory process on this issue and will strive to keep our consumers accurately informed.
Consumers can learn more about chromium in drinking water on the EPA website: