Hexavalent chromium is recognized as a human carcinogen. Some workers are exposed to the chemical, and exposure is known to sometimes occur among those who handle chromate-containing products, as well as those who arc weld stainless steel. The European Union has the world's strictest laws regarding hexavalent chromium. Hexavalent chromium use in the European Union in electronic equipment, for example, is largely prohibited by the Restriction of Hazardous Substances Directive.
Highest levels of hexavalent chromium in tap water were found in Norman; Oklahoma, Riverside; California, and Honolulu; Hawaii. Safety limits proposed by California regulators were exceeded in samples from 25 US cities, the scientists revealed.
Hexavalent chromium, also known as chromium-6 in drinking water shows "clear evidence of carcinogenic activity" in animal studies, significantly raising the likelihood of the development of gastrointestinal tumors.
An EPA (Environmental Protection Agency) draft toxicological review this year also found that tap water tainted with hexavalent chromium is "likely to be carcinogenic to humans".
A public health goal of 0.06 ppb (parts per billion) was proposed by Californian authorities in 2009, in an attempt to protect humans from cancer risk. The aim was to eventually set this limit nationwide.
Despite growing evidence of the dangers of hexavalent chromium in tap water, the EPA has done nothing about legal limit requirements. Water utility companies don't even have to test for levels in their tap water.
The average hexavalent chromium levels in the tested tap water was 0.18 ppb, compared to the recommended 0.06 ppb.
Top five cities tested:
- Norman, Oklahoma, population - 89,952
Hexavalent chromium level 12.9 ppb
- Honolulu, Hawaii: population - 661,004
Hexavalent chromium level 2.00 ppb
- Riverside, California, population - 280,832
Hexavalent chromium level 1.69 ppb
- Madison, Wisconsin, population - 200,814
Hexavalent chromium level 1.58 ppb
- San Jose, California, population - 979,000
Hexavalent chromium level 1.34 ppb
With so many tens of millions of Americans exposed to hexavalent chromium on a daily bases, the Environmental Working Group is urging the EPA to act - to set a legal limit on chromium-6, and make water utility companies regularly test levels of it in their tap water.
In a communiqué, the Environmental Working Group wrote:
"The state of California must establish a strong standard for hexavalent chromium in tap water immediately. A truly health-protective hexavalent chromium regulation will reduce the cancer risk for Californians and serve as a model for the nation. With an enforceable standard already six years past the statutory deadline and the health of millions of Californians at stake, the state cannot move too quickly."
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Source: Environmental Working Group