Chromium-6 In Honolulu's Tap Water

Original post below. Please read the endnote.
===================================
In 1996 the cancer-stricken residents of Hinkley, CA won a $333 million settlement from PG&E for contaminating their tap water with hexavalent chromium, which is commonly abbreviated as chromium-6. This was the basis of the 2000 movie Erin Brockovich starring Julia Roberts.

Fast forward to 2010: Tap water from 31 of 35 U.S. cities tested contains chromium-6 according to laboratory tests commissioned by Environmental Working Group (EWG). [Click for a summary of the EWG report.] The highest levels were detected in Norman, Okla.; Honolulu, Hawaii; and Riverside, California, as the table below shows.

City ------------------------ Population ----- Chromium-6 in Tap Water
Norman, Oklahoma ---------- 89,952 --------------- 12.9 ppb
Honolulu, Hawaii ----------- 661,004 --------------- 2.00 ppb
Riverside, California ------- 280,832 --------------- 1.69 ppb
Madison, Wisconsin -------- 200,814 --------------- 1.58 ppb
San Jose, California -------- 979,000 --------------- 1.34 ppb

The EPA has not yet set a limit for chromium-6 in water despite mounting evidence of the contaminant’s toxic effects, including an EPA draft toxicological review that classifies it as “likely to be carcinogenic to humans” when consumed in drinking water.

According to EWG, the National Toxicology Program has found that chromium-6 in drinking water shows clear evidence of carcinogenic activity in laboratory animals, increasing the risk of otherwise rare gastrointestinal tumors.

California officials last year proposed setting a public health goal for chromium-6 in drinking water of 0.06 parts per billion (ppb). The level of chromium-6 in Honolulu's tap water is 33 times over this proposed limit.
===================================
Note added on December 29, 2010: This article suggests that the Chromium-6 reported amount in tap water is of no consequence to human health.