This article was published on: 12/22/10 12:00 AM
Hexavalent chromium in Bend tap within EPA standard
Study of city’s water shows levels of possible carcinogen are well below agency’s mark, but above California’s proposed goal
By Kate Ramsayer / The Bulletin
Published: December 20. 2010 4:00AM PST
A test of tap water in 35 cities across the U.S. has found the possible carcinogen hexavalent chromium in 31 of those cities — including Bend.
The amount of the chemical found in Bend is significantly below the Environmental Protection Agency’s standard for total chromium in drinking water, but also exceeds a proposed goal for the state of California’s drinking water.
The study found concentrations of hexavalent chromium of 0.78 parts per billion in Bend’s tap water, which is below the EPA’s standard of 100 parts per billion of hexavalent chromium and another form of the chemical.
“The good news in all of this is it’s still below the one standard we have,” said Harold Rogers, EPA’s coordinator for the drinking water program in Oregon.
‘Need to be concerned’
But an author of the study from the Environmental Working Group, a nonprofit based in Washington, D.C., said that the results should encourage federal and state agencies to set standards for the chemical.
“We certainly need to be concerned about this contaminant in a much broader region of the U.S.,” said Rebecca Sutton, senior scientist with the Environmental Working Group, a nonprofit based in Washington, D.C.
Hexavalent chromium is a heavy metal that can get into water supplies either through the surrounding geology or from industrial sources, like plating operations or wood preservation industries, according to a fact sheet from the California Environmental Protection Agency.
A National Toxicology Program study using rodents has led to concerns that hexavalent chromium in drinking water can lead to cancer, according to the state.
And a study of people in China who were exposed to high levels of the chemical showed an increased rate of stomach cancer.
Because of this, California in 2009 drafted a proposed public health goal that would set 0.06 parts per billion as the level where hexavalent chromium does not pose a significant risk, meaning people could have a one-in-a-million risk of developing cancer from drinking water contaminated with that level. The public health goal is not designed to be the boundary between safe and harmful levels, according to the state’s fact sheet. And it’s not a standard, but something that policymakers can use to set standards.
The Environmental Working Group’s study found that tap water in 25 cities exceeded Cali-fornia’s proposed public health goal of 0.06 parts per billion of hexavalent chromium.
In Bend, a single tap water sample had 0.78 parts per billion of hexavalent chromium, according to the report.
The highest amount tested was in Norman, Okla., where the hexavalent chromium concentration was 12.9 parts per billion.
“These were just single samples. We wanted to broadly test a wide region of the U.S.,” Sutton said. “It’s kind of a snapshot — what’s our water like today.”
However, Steve Prazak, laboratory manager at Bend’s water quality laboratory, noted that the amount of hexavalent chromium found is well within the federal EPA standards.
“We are following EPA rules,” Prazak said. “And if EPA sets guidance levels (for hexavalent chromium), then you know for certain the city of Bend is going to jump all over it. We are going to follow.”
EPA sets the limit for total chromium — which includes both the harmful hexavalent version as well as trivalent chromium, an essential nutrient — at 100 parts per billion.
State records show that Bend’s regular water testing has not detected any chromium in the water since 2004, when the level of the two types of chromium was about 1.4 parts per billion. In 23 years, the city has detected total chromium 12 times, Prazak said, each time between 20 times and 100 times below the federal limit.
Prazak also noted that if tap water is not sampled correctly, the results could be skewed from airborne chromium or other factors.
“There’s a lot of variables here that would be interesting to look at,” he said.
Rogers, with the EPA, said he had questions about the sampling and testing procedure as well.
“There’s a lot of questions when somebody goes out and takes a tap sample themselves,” he said, such as the protocols from the laboratory or the plumbing in the location where the water was collected.
The EPA has not set any drinking water standards for hexavalent chromium alone, he said, so he couldn’t say whether a level of 0.78 parts per billion is of concern.
Marcia Bailey, a toxicologist with the EPA’s regional office in Seattle, said that the amount of hexavalent chromium found in Bend is not that high. The EPA does look at hexavalent chromium levels in Superfund sites, and that level wouldn’t trigger the agency to make a company clean up the chemical.
“It’s not huge,” she said. “If it were a manufacturing facility … we would not be alarmed by this number.”
Sutton, with the Environmental Working Group, said that it’s a personal choice for people whether they should be concerned about the presence of hexavalent chromium in drinking water. If people are worried, she said, they could install a reverse-osmosis water filter that is certified to remove the chemical.
Sutton said that with the broad occurrence of hexavalent chromium in drinking water, the group would like to see more sensitive testing specifically for hexavalent chromium.
California should move forward with approving a final public health goal for hexavalent chromium, and then set a safety standard for the chemical in drinking water, she said, adding that the federal EPA should set standards as well.
“We really want to see regulations that protect our health, and safety standards that guarantee clean drinking water,” she said.
Hexavalent chromium is a heavy metal,
and has been shown in studies to cause cancer in laboratory animals.
Another study of people exposed to high levels of the hexavalent
chromium showed they had an increased rate of stomach cancer, according
to the state of California.
The chemical can contaminate drinking
water through both natural deposits in rocks and industrial sources such
as chrome plating, said Harold Rogers with the Environmental Protection
Agency. Although both groundwater and surface water could be
contaminated with the chemical, it is probably more likely to be in
groundwater, he said, closer to the deposits.
Ways to treat drinking
water to get rid of hexavalent chromium include certain filtration
treatments, ion exchange and reverse osmosis, Rogers said.
Kate Ramsayer can be reached at 541-617-7811 or at email@example.com.
Published Daily in Bend Oregon by Western Communications, Inc. © 2010