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The Chicago Tribune recently published two articles, “Toxic chromium found in Chicago drinking water,” August 6, 2011 and  “Odd chemicals turn up in drinking water,” August 6, 2011, pertaining to two separate water quality issues. The first was a follow up on the levels of hexavalent chromium (CrVI) first reported in December of 2010. The second was in regards to levels of pharmaceutical and personal care products (PPCP) first reported in May of 2008. The common link was that both articles referred to the current regulatory levels for these compounds and what changes might be necessary in terms of public health.

The City of Evanston Water Division has voluntarily tested for both CrVI and PPCP in an effort to establish some base line historical values should treatment become mandated by the U.S. Environmental Protection Agency (USEPA). At this time, the Water Division continues to remain in compliance with all USEPA and Illinois Environmental Protection Agency (IEPA) standards and there is no maximum contaminant level (MCL) legislated for either of these compounds at this time.

Chromium is a metallic compound and is found naturally in rocks, soils, plants, and volcanic dust as well as in humans and animals. Total chromium is made up of trivalent chromium (which is an essential nutrient for humans), hexavalent chromium and the metallic form of chromium. The primary source of CrVI in drinking water supplies are caused by discharges from steel and paper manufacturing facilities.

The USEPA is asking that all large water suppliers collect data to assist the agency in determining if this compound should be regulated in addition to total chromium which is currently regulated with an MCL of 100 parts per billion (ppb). As outlined in the article, the State of California has instituted a public health goal of 0.02 ppb for CrVI. While this level is not mandated as an MCL designation at this time, the research done by the State of California has prompted the USEPA to take a closer look at regulating CrVI.

There are currently additional studies to determine if the State of California goal is based on solid enough scientific data to warrant an MCL designation at this level. There is a lot of debate in terms of the transformation of CrVI to trivalent chromium in the human body as the compound passes through the digestive system and it is clear that additional studies are necessary.

Evanston began testing for CrVI in January, 2011 and is committed to analyze samples on a quarterly basis until further notice. The results to date are as follows:

City of Evanston Chromium Test Results


Total Chromium

Hexavalent Chromium

January, 2011

0.20 ppb

0.27 ppb

April, 2011

0.30 ppb

0.22 ppb

July, 2011

0.40 ppb

0.23 ppb

As the data indicates, the levels of both total and hexavalent chromium found at Evanston are very similar to what has been found in all Lake Michigan water treatment locations in Illinois, Indiana and Wisconsin. The City of Evanston will continue to collect and analyze data on chromium in order to be prepared for any changes in regulations. These results are reported as they become available here on the City of Evanston’s web site>>>

The source of these products in drinking water stems from the use of prescription and over the counter drugs as well as from products such as insect repellents, tobacco and agricultural use by products. In most cases the occurrence of these compounds in water are due to the normal passage of the compound through the human body as well as improper disposal of the materials.

Most conventional waste water treatment systems are not designed to remove the low level concentrations that are being detected since testing for these products was initiated several years ago. Part of the issue is that the analytical techniques available today allow scientists to detect very low concentrations but there is no science to determine what, if any, deleterious health effects may exist from these extremely low levels. Remember, many of these compounds are being detected at the part per billion level and in some cases part per trillion levels. To add some perspective, a part per billion is equivalent to one penny in ten million dollars.

The City of Evanston began testing the finished drinking water for these compounds in May, 2008 and continues to test for these products on an annual basis. Two of the products reported in the Chicago Tribune article, gemfibrozil (cholesterol medication) and perfluorooctane sulfanate (also known as PFOS, product used to manufacture Scotchgard), were detected at very low levels. Additionally, cotinine, a byproduct of nicotine, was also detected during all sample periods. A summary of the occurrences is below:

City of Evanston Pharmaceutical & Personal Care Products (PPCP) Test Results



Level Detected

May, 2008


0.001 ppb

May, 2008


0.003 ppb

July, 2009


0.001 ppb

November, 2009


0.0021 ppb

November, 2010


0.002 ppb

November, 2010



The testing for these compounds will continue on an annual basis so that if regulations are established, the Water Division has a baseline of data to use in the selection of a proper treatment technique. While currently not required, the results of these tests are reported annual in our Consumer Confidence Report on Water Quality which can be found here>>>

The Evanston Water Division is committed to stay at the forefront of testing and treatment technology and will continue to provide safe drinking water to the residents of Evanston and our wholesale water customers.