Chromium-6 Questions and Answers
(Updated Aug. 10, 2011)
What is chromium-6?
Chromium-6, or hexavalent chromium, is a naturally occurring metal. It is also used in several industrial processes. There are other forms of chromium. Another form, chromium III+, is an essential nutrient for the body and is sold as a dietary supplement.
Is there a drinking water standard for chromium-6?
No. California has had a drinking water standard of 50 parts-per-billion (ppb) for total chromium for many years, but does not yet have a standard specifically to regulate chromium-6. Chromium-6 is one component that makes up total chromium.
- California is the only state that is currently in the process of developing a drinking water standard for chromium-6.
- In July 2011 California state scientists released a public health goal (PHG) of .02 ppb for chromium-6, in drinking water. This completes the first step in the rigorous process of developing the first regulatory drinking water standard in the nation specifically for chromium-6.
- It will take several years before the state establishes a maximum contaminant level (MCL) for chromium-6.
What is the safe level of chromium-6 in drinking water?
It’s too early to say. State and federal regulatory agencies are studying the possible health effects of chromium-6 and will use that data to determine a drinking water standard.
Does Santa Clara Valley Water District test for chromium-6?
We test water produced at our three drinking water treatment plants for chromium-6. To date, we have never detected chromium-6 in our treated water at the state certified reporting limit of 1 ppb. This is the lowest level of detection that is currently available for a state certified laboratory. In January 2011, our laboratory began preliminary work to achieve a lower reporting limit. In developing an advanced testing method, we conducted a round of sampling at our three treatment plants and found chromium-6 in the 0.06 to 0.09 ppb range. This lower reporting level is not yet approved, and staff will be working with the California Department of Public Health to determine the next steps in obtaining certification.
As part of the California Dept. of Public Health’s process of establishing a drinking water standard, some water providers all over the state were asked to test their water supplies for chromium-6. To better understand the occurrence of chromium-6 in groundwater, the District tested wells around the county between 2001 and 2004. The median level detected in Santa Clara County was 1 ppb, and the range varied from below the 1 ppb reporting limit, up to 23 ppb.
Does chromium-6 cause cancer?
Chromium-6 is being evaluated by federal and state regulatory agencies as a suspected carcinogen in drinking water.
Does San Jose have one of the highest levels of chromium-6?
We don’t know. Many water supplies have not been tested for it, since chromium-6 is not a regulated chemical. The recent Environmental Working Group study took single samples from each of only 35 cities in the United States, and only four cities in California. This study and other data suggest that chromium-6 is present in water supplies throughout the country. While San Jose was included in EWG’s sample, we cannot conclude that San Jose has more or less chromium-6 than any other city that was not sampled.
While EWG only tested water in four California cities, the California Department of Public Health has posted on its website the results of chromium-6 monitoring tests from locations throughout California.
Is this the chemical that was the subject of the movie, "Erin Brockovich"?
Yes, it is. In Hinkley, California, chromium-6 has been detected in wells at a level of up to 3,390 parts per billion (ppb). By comparison, the EWG study reported a level of 1.34 ppb in its San Jose sample.
How does chromium-6 get into water supplies?
Chromium-6 can be naturally occurring in rocks and soil, so it may be present in some groundwater aquifers. It can also reach water supplies from industrial uses such as stainless steel production, metal plating, and leather tanning.
Is there a filter that will remove chromium-6?
The California Dept. of Public Health has a list of devices certified to reduce chromium levels on its website. However, the department does not specify how much reduction can be expected from each device.
Is chromium-6 found in bottled water?
There is no chromium-6 standard for bottled water, so bottled water producers are not required to test for it. We suggest consumers contact bottled water producers directly for information about their product’s water quality.
What is the Santa Clara Valley Water District doing to address this issue?
- We will continue to provide accurate information to the public.
- We are coordinating with our local water retailers to respond appropriately.
- We are actively engaged in the state and federal process to establish a science-based drinking water standard for chromium-6
- We continue to monitor new science regarding chromium-6 and other unregulated contaminants.
Statement from CEO Beau Goldie
On Dec. 20, 2010, the advocacy group, Environmental Working Group, released results of a study it conducted on the presence of chromium-6 in drinking water around the United States. The study included a single water sample taken from each of 35 cities around the country, including a sample from an unidentified location in San Jose. According to the study, all but four of the samples contained a measurable amount of chromium-6.
While we understand that EWG strives to call attention to the presence of chromium-6 in many water supplies all over the country, it is not known whether or not the level that was reported poses a health risk. While there is a state and federal standard for total chromium, there is currently no drinking water standard for chromium-6.
We support the process that state and federal regulators are conducting to evaluate the latest science and establish a safe drinking water standard for chromium-6 to protect public health. We are encouraged by the U.S. EPA’s announcement on Dec. 22, 2010, that the agency will take immediate steps to increase monitoring and sampling programs specifically for chromium-6. The EPA is in the process of conducting a scientific peer review of the potential health risks of long-term exposure to chromium-6. This is an essential step in the process of developing a science-based drinking water standard.
As always, the Santa Clara Valley Water District is committed to protecting public health. We actively monitor new scientific research related to drinking water standards, and we are fully engaged in the state and federal process to develop a chromium-6 drinking water standard. We will continue to provide information to the public, and to coordinate with our local retail water suppliers.
Meanwhile, we continue to provide high quality drinking water that meets or exceeds all applicable U.S. Environmental Protection Agency and California Department of Public Health regulations.