Drinking Water Quality for Chromium - 6

Recent print and broadcast news media has reported that a Washington DC based environmental research and advocacy group has sampled water samples from several U.S. cities, including Chicago, to measure levels of toxic metals. One particular metal being reported is hexavalent chromium, also called chromium-6.

Articles have been published in the Washington Post, Chicago Tribune and the Riverside California Press Enterprise to name a few. Senators Durbin and Kirk have also weighed in on this news requesting
United States Environmental Protection Agency (USEPA) to act nationwide in a manner similar to the State of California which is close to promulgating a chromium-6 standard of 0.06 parts per billion (ppb).

Affecting Bloomingdale
The Village of Bloomingdale is 1 of 25 members of the DuPage Water Commission that purchases treated Lake Michigan drinking water from the City of Chicago. The Lake Michigan water is treated at the Jardine Facility north of Navy Pier. The press release (PDF) from the City of Chicago regarding chromium-6 levels in City of Chicago treated water.

Drinking Water Standards
Current the USEPA drinking water standards do not require the City of Chicago to treat the Lake Michigan water supply for chromium-6. The city does test for chromium-6. It has been reported that chromium-6 levels in Chicago drinking water was 0.18 ppb which complies with current the USEPA standards.

Creating Standards
Established in 1992, the current Maximum Contaminate Level Goal (MCLG) for chromium (total) is 100 ppb. EPA had set this level of protection based on the best available science at the time to prevent potential health problems.

The USEPA sets maximum contaminant level is set as close to the health goals as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies. However the USEPA is currently evaluating new science regarding the health effects of ingesting drinking water containing trace amounts of chromium-6 which results may be cause to establish a new maximum contaminant level for drinking water lower than the current standard.

A report from the USEPA regarding chromium-6 is expected in late 2011.

Drinking Safe Water
As documented in the village's Annual Drinking Water Quality Reports posted on the village's website, the Lake Michigan drinking water supply is safe to drink meeting the current the USEPA drinking water standards. A link to the press release from the City of Chicago is included with this posting also indicating the drinking water supply is safe to drink.

Well Water v. Surface Water
In reviewing information reported in the print media, chromium-6 levels appear to be in higher concentrations in ground water supplies (wells), when compared to levels detected in surface water supplies such as water from Lake Michigan.

When Bloomingdale converted its water supply from ground water wells to Lake Michigan water in the early 1990's, it retained, and to this day maintains in a ready state, 3 of its ground water wells as ‘emergency' back-ups in the event of failed delivery of the DuPage Water Commission Lake Michigan supply.

Over the past many years, the DuPage Water Commission water supply has proven to be highly reliable - to date the village has not needed to use any of its ground water wells, in whole or part, to supply the village with water in response to an emergency or otherwise.

Water Treatment
According to the the USEPA web site, treatment methods which have proven to be effective for removing chromium (total) to below 100 ppb include coagulation / filtration, ion exchange, reverse osmosis, lime softening. The treatment method or methods necessary to treat Lake Michigan water to a more stringent standard remains to be seen and would depend on the standard established by the USEPA.

There remains some debate as to whether the source of the chromium-6 is in the surface water supply itself, or a consequence of chromium leaching from home plumbing system pipes faucets and the like - a point that also must be evaluated by the USEPA.

Home Treatment
Some residents may ask if home treatment systems are effective in treating chromium-6 in drinking water. Cursory website research of some recognized manufacturers of relatively inexpensive ‘over-the-counter' faucet/pitcher type home treatment / filtration systems have published claims that its products are effective reducing levels of certain metals such as zinc, copper, lead, cadmium and mercury; but this research has yet to find any claims specifically listing treatment of chromium-6 or total chromium. Professionally installed, and certainly more expensive, home reverse osmosis systems may likely be effective but should be evaluated fully before installing.

Continuing Research
For now the environmental advocacy and news media reports have raised an important question which requires further careful study and evaluation by the research community and the USEPA as to the health effects of ingesting drinking water containing trace amounts of chromium-6.

It was once assumed that the human body could convert small levels of chromium-6 to an essential nutrient chromium-3; but it appears that the new science is pointing to the need to reevaluate the chromium-6 standard.

The only certainty at this time is that continued study and evaluation by the USEPA is needed.

New Standards
Should the USEPA establish a new standard for chromium-6 levels which requires treatment of the Lake Michigan water supply, the village believes that both the City of Chicago and DuPage Water Commission are prepared to respond in a reasonable, responsible manner that protects public health and meets federal and state standards.

Additional Information
Please contact Village Services by email or telephone at 630-671-5690 should you have any questions.