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发帖数: 2053 | 1 http://www.nytimes.com/gwire/2010/12/20/20greenwire-probable-carcinogen-found-in-tap-water-of-31-us-4856.html
By ELANA SCHOR of Greenwire
Published: December 20, 2010
In 25 of 35 U.S. cities where tap water supplies were tested for hexavalent
chromium -- deemed likely to cause cancer in humans in a U.S. EPA draft
review this year -- levels of the chemical exceeded the minimum set by the
state of California to protect public health, according to a report released
today by an environmental group.
The Environmental Working Group's (EWG) new findings mark a public flare-up
in the behind-the-scenes battle over estimating the carcinogenicity of oral
exposure to hexavalent chromium, also referred to as chromium-6. The draft
EPA assessment released in September could pave the way for a national
drinking-water standard for the chemical, best known for polluting
groundwater in Hinkley, Calif., where activist Erin Brockovich won a
multimillion-dollar settlement for locals and became a household name.
The outcry over cancer cases in Hinkley helped push California to set a tap-
water public health goal of 0.06 parts per billion (ppb) of chromium-6, an
early move on the way to a binding state standard (Greenwire, Aug. 21, 2009)
. Of the 35 cities where EWG tested drinking supplies, 31 contained some
level of chromium-6, and 25 -- including Washington, Los Angeles and Norman,
Okla., where samples showed 12.9 ppb -- contained levels higher than the
California goal.
EWG senior scientist Rebecca Sutton, an environmental chemist who crafted
today's report, said her group's data provide new ammunition for measuring
and restricting chromium-6 in drinking water nationwide. The federal
government made "a very poor choice" by mandating its current drinking-water
tests for total chromium, a metric that blends hazardous chromium-6 with
the essential nutrient trivalent chromium.
Sutton added that while "industry is doing its very best to slow the process
down even further," she hopes to see California advancing its chromium-6
limits to serve as a potential model for broader action. "Sometimes the
state of California can lead the way, can show, 'Hey, this is possible,'"
she said.
Brockovich, now an author and full-time consumer advocate, predicted in an
interview that further chromium-6 water contamination issues would emerge "
not only at a national but a global level."
"There is no reason why we can't address this without sounding some kind of
panic alarm, which [critics] are going to accuse us of doing," Brockovich
said.
A heavy metal commonly used in industrial dyes and coatings that also occurs
naturally in small amounts, chromium-6 is known to be carcinogenic via
inhalation. The cancer-causing effects of oral exposure through water,
however, remain the subject of intense debate between environmentalists and
industry.
The recent EPA draft review of chromium-6 incorporated the results of a 2008
National Toxicology Program (NTP) study that found a higher occurrence of
gastrointestinal tumors in exposed rodents. The American Chemistry Council
and the American Water Works Association, which represents water utilities
that could bear the costs of broader chromium-6 testing, have both
questioned the application of the NTP study to human exposures at lower
levels.
ACC and AWWA have called on EPA to postpone further action on its chromium-6
risk assessment until new studies, including one funded by industry, are
released next year.
A senior official at the Southern California Water Committee (SCWC), an
alliance of industry and local governments active on water quality issues in
the state, also asked EPA to delay the chromium-6 assessment until more
studies are released.
Using the 2008 NTP data to assess the cancer-causing effects of lower
exposures to chromium-6 "may not reflect the true risk and will have
significant consequences for the public's confidence in the quality and
safety of their drinking water," SCWC Executive Director Richard Atwater
wrote to EPA in October. "Furthermore, it would prematurely trigger
regulatory levels that water supply agencies simply don't have the equipment
to monitor and detect."
Click here to read EWG's full report on hexavalent chromium in drinking
water.
http://static.ewg.org/reports/2010/chrome6/html/home.html
Copyright 2010 E&E Publishing. All Rights Reserved.
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