Chromium-6 in U.S. Tap Water: Government Failings
EPA slow to set drinking water limits for chromium-6
Despite growing recognition of hexavalent chromium’s carcinogenic potential, including EPA’s draft designation of it as a likely human carcinogen, the agency has taken no action to limit levels of this toxic compound in drinking water. The agency has left in place an inadequate standard for total chromium, set nearly 20 years ago, that does not distinguish between toxic hexavalent and nutritionally essential trivalent chromium and cites “allergic dermatitis” as the only relevant health concern.
The EPA has reviewed its standard for total chromium twice since setting it in 1992. In 2003, the agency determined that even though new research on chromium-6 indicated cause for concern, information gaps prevented establishment of a more protective standard (EPA 2003). Six years later, the EPA again delayed action on a stricter standard, this time because it had initiated an evaluation of hexavalent chromium via its Integrated Risk Information System (IRIS) (EPA 2009). The draft toxicological review released in September as part of this process identified exposure to hexavalent chromium in drinking water as likely to cause cancer to humans, and cited animal studies linking it to a variety of other health effects, including anemia and damage to the gastrointestinal tract, lymph nodes and liver (EPA 2010a).
Drinking water standards are drastically out-of-date
The EPA’s inaction is but one example of the agency’s lack of resolve in protecting Americans’ tap water. The agency has not set a new, enforceable drinking water standard for any contaminant since 2001, even though the Safe Drinking Water Act requires the EPA to assess the need for standards for at least five new chemicals every five years. Three-fourths of the current standards, including for total chromium, were set in 1991 and 1992 and have not been updated since.
Since 1996, the EPA has reviewed data on toxicity and water pollution for 138 chemicals, but in every case it declined to set a safety standard. EWG's analysis of its tap water quality database showed that collectively these chemicals pollute drinking water used by more than 111 million Americans (EWG 2009).
The framework under which the EPA sets drinking water standards is outdated. For example, the agency is not required to set maximum legal limits for contaminants at levels that protect the health of children or to consider the heightened vulnerability of the fetus and newborns (Donohue 2002).
In addition, the EPA sets maximum legal limits for contaminants as if people are exposed to just one at a time. That’s not the reality — research shows that people carry hundreds of chemicals in their bodies at any given time. A growing number of studies also show that the risks add up when people are exposed to multiple chemicals that can act in tandem to cause harm — and that total risk can be greater than the sum of the parts (NRC 2008).
At long last, signs of progress
For the 114 contaminants that the EPA does regulate, EWG’s drinking water quality analysis found that water suppliers achieved 92 percent compliance with mandatory health standards, demonstrating that utilities can and do meet enforceable limits when they exist (EWG 2009). However, the EPA’s failure to develop meaningful standards for hexavalent chromium and scores of other contaminants leaves the public at risk.
Recently the federal government has begun to focus a critical eye on hexavalent chromium and other water contaminants. When EPA Administrator Lisa Jackson took office, she announced that protecting America’s drinking water would be one of seven agency priorities. In keeping with this goal, the EPA has announced plans to set a legal limit for perchlorate in tap water, which would make it the first new chemical to be regulated in drinking water in a decade. Meanwhile, the Toxic Chemicals Safety Act (H.R. 5820), introduced in the House of Representatives this summer, specifically lists hexavalent chromium as a priority chemical for safety evaluation.
EWG recommends that the EPA set a legal limit for hexavalent chromium in drinking water as quickly as possible and require all water utilities to test for it. The EPA can speed the process by streamlining the IRIS assessment. We hope that Administrator Jackson’s leadership on this critical issue will reduce cancer risk for all Americans.