Patient concerns have not been quelled by the recent results from a broader sampling of Oahu’s drinking water. The state Department of Health came out again to proclaim Oahu’s drinking water safe but also promised to study levels of hexavalent chromium (chromium 6) at all 100 pumping stations islandwide. The controversy arose in December when the Environmental Working Group took a single sample from a residence on Wilhelmina Rise. It found 2 parts per billion (ppb) of chromium 6, which was the second-highest level among 35 cities tested in the United States. The recent sampling of 11 pumping stations showed levels of 0.32 to 4 ppb.

The public first became sensitized to the health risks of chromium 6 after watching the movie "Erin Brockovich," starring Julia Roberts, in which the residents of Hinckley, Calif., won a class-action lawsuit against Pacific Gas and Electric Co. in 1996. Chromium 6 levels found in Hinckley were far higher than any values to date on Oahu.

Chromium 6 can be dangerous and has been associated with an increased risk of certain cancers. Chronic exposure has been shown to result in DNA damage and gene mutations. Trivalent chromium (chromium 3), on the other hand, is a human nutrient. The problem is that when chromium 6 enters the body, it does its damage rather quickly and then converts to chromium 3. As such, it is not possible to test blood levels for the more toxic form.

The greatest challenge in accurately assessing the chromium 6 risk in Hawaii is that the Environmental Protection Agency has not established a maximum acceptable level. Although it has established standards of no more than 100 ppb for total chromium in drinking water, this standard is meaningless because it combines both chromium 3 and chromium 6 levels. California, however, has recommended that chromium 6 levels alone not exceed .06 ppb, and all of the 11 samples from Hawaii exceed that number.

Whether the current levels of chromium 6 found in the recent sampling come from local, naturally occurring volcanic soils or industrial exposure is not clear.

The truth is, we don’t know whether Oahu’s chromium levels are safe. To resolve this question, additional sampling of all 100 pumping stations on Oahu will be helpful. At the same time, the EPA needs to establish a formal standard for maximum levels of chromium 6 in drinking water and separately for water that comes into contact with the skin. In response to public pressure resulting from the samples taken by the EWG, EPA Administrator Lisa Jackson announced Wednesday that the agency is likely to propose limits for chromium 6, at least for drinking water.

In the meantime, those most concerned are beginning to use mainland labs to check the chromium 6 levels of water they drink at home and at work. Unfortunately, local labs do not offer this test. Others, to be on the safe side, are beginning to use water purification systems based on reverse osmosis or distillation. A simple charcoal filter will not remove chromium 6.

To date, there is no cause for grave concern, but the people of Oahu should remain vigilant.

Ira Zunin, M.D., M.P.H., M.B.A., is medical director of Manakai o Malama Integrative Healthcare Group and Rehabilitation Center and CEO of Global Advisory Services Inc. Please submit your questions to info@manakaiomalama.com.