Ask the Doctors

Dear Doctor: Just how unsafe is chromium-6, the chemical at the heart of the movie "Erin Brockovich"? I read that it's still in the water in some parts of the country. How is that possible? How do I find out about water quality in my area?

Dear Reader: While the characters and events in "Erin Brockovich" may have been embellished to serve the dramatic arc of the story, chromium-6, when present beyond certain concentrations, is as toxic as the film portrayed. Breathed in, it can cause lung cancer. Ingested, it has been linked to liver and kidney damage, serious reproductive problems, rashes and skin conditions, and developmental harm to infants and children.

Chromium is a metallic element that occurs naturally in soil, rocks, plants and volcanic dust. It is found in several forms, including chromium-3, an essential micronutrient that plays a role in the breakdown of fats, proteins and carbohydrates. Chromium-6, by contrast, is a toxic form of the element. Also known as hexavalent chromium, it's a byproduct of the natural chemical breakdown of chromium and is created in greater quantities through various industrial processes.

Both forms of chromium are used in applications such as chrome plating, making pigments and dyes, the manufacture of stainless steel, preserving wood and leather products, and, as depicted in "Erin Brockovich," in the treatment of water in cooling towers. Exposure to large amounts of any kind of chromium, which has numerous uses in manufacturing, has been known to cause respiratory problems like shortness of breath, wheezing, cough and even asthma.

When industrial users of chromium-6 fail to take proper precautions when they store or dispose of the chemical, leakage and runoff from the manufacturing process can pollute the groundwater. And while the EPA has set a limit on what it refers to as "total chromium," the sum of chromium-3 and the far more toxic chromium-6, at this time it has not set a limit solely for chromium-6. California, home to the landmark chromium-6 lawsuit at the heart of "Erin Brockovich," has placed a legal limit on chromium-6 concentrations in the water, but some activists believe the allowable levels remain too high.

You've posed an important question when you ask about how chromium-6 continues to enter our drinking water supply. But the answer is complex. Providing potable drinking water to a nation as vast and populous as the United States remains an ongoing challenge. Since the establishment of the Clean Water Act in 1972, health and safety standards have been set at the federal level. However, water is a regional resource. That means oversight of the tens of thousands of state, local and private water utilities that make sure our taps are flowing falls to a complex patchwork of regulatory agencies. As a result, water quality can vary greatly depending on where you live.

If you live in a community whose water system serves more than 100,000 people, it is required to post reports on water quality online. If you live in a smaller community, check with your local government agency to learn where and how to find reports regarding your specific provider. For more information, go to water.epa.gov/drink/index.cfm.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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