Chromium-6 — a known carcinogen — has been found in the drinking water of more than 200 million Americans throughout the country including in DuPage County, according to the Environmental Working Group.
Chromium-6, or hexavalent chromium, is an odorless, tasteless, naturally-occurring form of the metallic element chromium. It can be found naturally in rock, soil, ore, volcanic dust, plants and even animals or humans. Chromium-6 is also a byproduct of industrial processes like stainless steel production, leather tanning and textile pigmentation. Improper disposal, leakage or poor storage can cause it to appear in drinking water.
The issue of chromium toxicity was first made widely popular by “Erin Brockovich,” a film depicting the true story of the eponymous environmental activist who unveils the cover-up of carcinogenic chromium-6 in the water of a small California town.
California now has a public health goal — their own guidelines for chromium-6 concentrations — of 0.02 parts per billion (ppb), far lower than the state’s legal limit of 10ppb. North Carolina and New Jersey recommend less than 0.06ppb. Both values were determined based on scientific recommendations, noting that even small amounts of this chemical can be carcinogenic.
DuPage County is one of 140 Chicago-area water systems that has chromium-6 in its public drinking water. Based on testing conducted between 2013 and 2015, the average for the Wheaton community is 0.20ppb, exceeding the levels recommended by California, New Jersey and North Carolina groups by 10 times.
The highest average level in a population — 29.59ppb — was found in Cleveland County, Okla., according to a study by the EWG. The highest in Illinois was in Woodford County, with the average reaching 3.83ppb in drinking water.
Overall, Chicago’s average chromium-6 level was ranked 11th highest out of 23 in a list of the largest U.S. water systems, according to EWG measurements.
The Environmental Protection Agency set regulations for total chromium in drinking water at less than 100ppb in the 1990s, though no limit has been set regarding the concentration of chromium-6 specifically.
However, the lack of federal regulation does not mean its presence is necessarily harmless. The Centers for Disease Control and Prevention stated that chronic chromium-6 inhalation is linked to increased risk of respiratory system cancers. A 2008 study by the National Toxicology Program found that the chemical caused cancer in lab rodents that drank polluted water.
The EWG estimates that some current levels of chromium-6 in tap water could cause 12,000 excess cases of cancer by the end of the century.
According to the DuPage County Health Department, Wheaton’s public drinking water systems are regulated by the Illinois Environmental Protection Agency. The state EPA said on their website, “It is very important that we start with a sound understanding and assessment of what we know relative to total chromium in Illinois ground and surface water, including Lake Michigan, used as a source of public water supply.” A Chromium-6 Strategic Plan is also in place.