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Chromium-6: Separating Fact from Fiction


By Michele Hatton

A few months ago, an odd report came out of the California-based Environmental Working Group (non-scientific) claiming that Tallahassee along with several other cities had above normal levels of chromium-6 in their drinking water. In response, the city initiated a detailed scientific analysis only to confirm what it already knew: that chromium levels in city water are low, very low, below the maximum level presently allowed by a factor of almost 100. So, why all the fuss?

Let’s define the terms. Chromium is an odorless, tasteless metallic element that comes in several different forms. Two common forms include chromium-3, which occurs naturally and is an essential trace element (read your vitamin/mineral label) and chromium-6 (hexavalent chromium), which may occur naturally but is most commonly associated with industry. Major industrial sources of chromium-6 in drinking water come from steel and pulp mills.

Chromium-6 however is a hot topic right now. Since 2008, the Environmental Protection Agency (EPA) has been engaged in rigorously reviewing of chromium-6 and its effect on human health. The maximum level of total chromium (forms -0, -3, and -6 combined) allowed in drinking water is 100 parts per billion (ppb). Sometime this year, the EPA will re-evaluate this number and most likely lower it. Magnetic Laboratory Geochemist Dr. Vincent Salters say, “Everybody agrees that the EPA will change the standard. OSHA recently lowered the standards for hexavalent chromium in the workplace where you have airborne chromium. They changed it by a factor of 50.”

Burt, how much chromium is in our water? The annual report shows the 2009 total chromium range was between non-detectable and 2.5 ppb. And what did the Environmental Working Group find? 1.25 ppb of chromium-6.

“For the past 35-40 years, chromium levels [in city water] haven’t changed, which tells us that chromium is naturally occurring,” says Jamie Shakar, Water Quality Manager for the City’s Underground Utilities. In fact, our city has a stellar, nationally recognized, water quality laboratory. It regularly tests water samples for the presence of more than 20 metals, including chromium, and does so far more often than required by law.

The Floridan Aquifer is also working hard on our behalf. “The limestone and clay lenses [in the aquifer] contribute to a huge filter. It’s a 200-foot deep filtration system,” claims Shakar. Add to this the enormous buffering capability of our limestone mega-structure. Hydrologist, Dr. Tom Kwader of URS Corporation says that in general, metals are more likely found in acidic water. “Here, we have 7.6 - 7.9 ph [more basic] which is not conducive to transporting metals [like chromium]. They would probably absorb and transfer out quickly.” He speculates that the high calcium levels in Tallahassee water may also benefit women.

The general consensus is that the Environmental Working Group wants to bring public attention to what they view as a “chromium-6” crisis. A health organization in California has proposed that 0.02 ppb should be the new standard, but this is based on one study only and has not undergone peer review. This cannot be considered a scientific claim by any stretch.

For a handful of highly industrialized cities, chromium-6 may become an issue if standards change. Primarily, it will be an economic burden for these cities, which will need to invest in the required filtering systems. But here, in Tallahassee, we have clean, good-tasting, intensely monitored water. In fact, some geologists in the area think our water may be some of the best in the world!

If you are still concerned and interested in purchasing a water filter to reduce any substance, including chromium-6, in your drinking water, the EPA has compiled a list of home treatment units that have been certified through NSF International and the Water Quality Association. For details, visit http://www.nsf.org/Certified/DWTU/ or http://www.wqa.org/sitelogic.cfm?id=1165.

The best way to navigate through these websites is to scroll down to “Reduction Claims.” Check which substances you want filtered and press Submit. Then choose the type filtering system you want: under the counter filter, whole house, pour through, etc.


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