Area water officials on Tuesday questioned an environmental group's report that lists Buffalo as one of 31 cities that may have a risky level of a chemical thought to cause cancer.
They cautioned that it's unclear what level of hexavalent chromium in water is potentially unsafe and recommended waiting to see the results of a review expected late next year by federal authorities.
"Everything is speculative until we see the studies and the EPA [Environmental Protection Agency] makes a ruling. Whatever the outcome, we'll comply with it," said Paul J. Whittam, director of water quality at the Erie County Water Authority.
The Environmental Working Group said its volunteers took water samples in 35 cities and found detectable levels of the chemical, also known as chromium 6, in 31 of them. Of those, 25 cities had levels above a strict measure proposed last year by the state of California.
Buffalo ranked 25th out of the 31 cities, with a proportion of chemical to water of 0.07 parts per billion.
The average level in the studied cities was 0.18 parts per billion. The proposed "public health goal" in California is 0.06 parts per billion. If California sets a limit, it would be the first in the nation.
The EPA has not set a legal limit for hexavalent chromium in tap water nationally and does not require water utilities to test for it, although the agency is reviewing its policy.
The chemical is commonly discharged from steel and pulp mills as well as metal-plating and leather-tanning facilities, according to the Environmental Working Group. Chromium 6 also can leach into groundwater from natural ores.
Currently, state and federal drinking water regulations address total chromium -- a combination of chromium 6 and chromium 3, a nutrient. For total chromium, the EPA's legal limit is 100 parts per billion in tap water to protect against skin irritation.
Last year, the water quality reports for the Erie County Water Authority and Buffalo Water Board reported no detectable levels of total chromium.
"Our water is safe," said Peter Merlo, city engineer in Buffalo, whose water was tested for the report. "We meet or are below every current standard."
However, like Whittam, Merlo said the report should be taken seriously, and he expressed hope that federal officials will provide guidance in the future on whether and how to measure chromium 6.
Hexavalent chromium received public attention in the 2000 film "Erin Brockovich" and has been found to cause cancer in laboratory animals by the National Toxicology Program, part of the National Institutes of Health.
Although basic water filters such as those made by Brita and PUR do not remove hexavalent chromium, several reverse-osmosis systems designed for home use can take the chemical out of water.
Bottled water is not necessarily an alternative because it is often drawn from municipal water systems and can still contain hexavalent chromium or other contaminants.
The analysis by the Environmental Working Group of Washington, D.C., is the first nationwide look at hexavalent chromium in drinking water to be made public.
"This definitely raises the issue about a national drinking water standard for hexavalent chromium and why we don't have one," said Lynn Goldman, an epidemiologist and former top official at the EPA who now serves as dean of the School of Public Health at George Washington University.
Goldman said the new study demands deeper investigation. "This is the very first signal that there might be a problem," she said. "But it's premature to say we know really what the level [of contamination] is, whether it's there all the time or just intermittently, and what the source is."
It has long been known that hexavalent chromium causes cancer in humans if it is inhaled. But in the past several years, researchers have found it causes cancer in animals when it is ingested.
Public awareness about the possible health effects of hexavalent chromium was heightened when residents of Hinkley, Calif., accused Pacific Gas & Electric of leaking the chemical into groundwater for more than 30 years. The company paid $333 million in damages in 1996 and pledged to clean up the contamination. The case was the basis for the movie "Erin Brockovich."
But a recent California study found that cancer levels in Hinkley are not elevated.
"People have been left with the impression from lawsuits and the movie that there is an excess of cancer in the community, but there is not," said John W. Morgan, the epidemiologist conducting the cancer studies.
Still, Morgan said, no one should draw a conclusion from the Hinkley studies that hexavalent chromium poses no health risk.
The dearth of human health-effect studies of chromium 6 in water makes it difficult to draw firm conclusions about what to do. Experts disagree over what level of chromium 6 in water is unsafe and whether the environmental group's proposed "unsafe" level is too strict.
"There is uncertainty in the science. I wouldn't necessarily worry about it, but I would also say that we need to be cautious and have further studies," said Edwin van Wijngaarden, an associate professor of community and preventive medicine at the University of Rochester.
The American Water Works Association, which represents water utilities, said that while the group's report may raise concerns, detecting a substance in water does not always imply a health risk.
The key question to answer is whether the substance presents health concerns at the level it is detected, the group said.
News Staff Reporter Henry L. Davis and the Washington Post contributed to this report.