Although Louisville’s tap water has been dubbed “Best Tasting” by the American Waterworks Association, that refreshing, metallic tang you detect every time you take a good swig of Ohio River aqua has earned our fair city a new distinction: We are now among 25 American cities whose tap water contains unsafe levels of carcinogenic hexavalent chromium.
Per new safety regulations proposed by the state of California, Louisville ranks 22nd out of 25 communities whose drinking water contains unsafe levels of hexavalent chromium, aka chromium VI (aka a major plot element in “Erin Brockovich“).
Today marks the release of a new study conducted by The Environmental Working Group (EWG), marking the first time such a study involving tap water contamination of chromium six has been made public.
Tap water from 31 of 35 U.S. cities tested contains hexavalent chromium (or chromium-6), the carcinogenic “Erin Brockovich chemical,” according to laboratory tests commissioned by Environmental Working Group (EWG). The highest levels were detected in Norman, Okla.; Honolulu, Hawaii; and Riverside, Calif.
Despite mounting evidence of the contaminant’s toxic effects, including a U.S. Environmental Protection Agency (EPA) draft toxicological review that classifies it as “likely to be carcinogenic to humans” when consumed in drinking water, the agency has not set a legal limit for chromium-6 in tap water and does not require water utilities to test for it. Hexavalent chromium is commonly discharged from steel and pulp mills as well as metal-plating and leather-tanning facilities. It can also pollute water through erosion of soil and rock.
The National Toxicology Program has found that hexavalent chromium in drinking water shows clear evidence of carcinogenic activity in laboratory animals, increasing the risk of otherwise rare gastrointestinal tumors (NTP 2007, 2008). In response to this study and others, California officials last year proposed setting a public health goal for chromium-6 in drinking water of 0.06 parts per billion (ppb). This is the first step toward establishing a statewide enforceable limit (OEHHA 2009).
And here’s some background on the issue, courtesy of The Washington Post:
The federal government restricts the amount of “total chromium” in drinking water and requires water utilities to test for it, but that includes both trivalent chromium, a mineral that humans need to metabolize glucose, and hexavalent chromium, the metal that has caused cancer in laboratory animals.
Last year, California took the first step in limiting the amount of hexavalent chromium in drinking water by proposing a “public health goal” for safe levels of 0.06 parts per billion. If California does set a limit, it would be the first in the nation.
Hexavalent chromium was a commonly used industrial chemical until the early 1990s. It is still used in some industries, such as in chrome plating and the manufacturing of plastics and dyes. The chemical can also leach into groundwater from natural ores.
The new study found hexavalent chromium in the tap water of 31 out of 35 cities sampled. Of those, 25 had levels that exceeded the goal proposed in California.
For a snapshot of how Louisville ranks, peep this graphic from EWG: