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Los Angeles
Times
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June 1, 2000, Thursday, Orange County Edition
SECTION: Metro; Part B; Page 1; Metro Desk
LENGTH: 986 words
HEADLINE:
WATER DISTRICT CLOSES 2 WELLS CONTAMINATED BY CHEMICAL;
WELLS IN COSTA
MESA AND HUNTINGTON BEACH HAD EXCESSIVE LEVELS OF SUSPECTED CARCINOGEN.
OFFICIALS SAY THERE IS NO THREAT TO PUBLIC HEALTH.
BYLINE: SEEMA MEHTA, TIMES STAFF WRITER
BODY:
Two public drinking water wells in Costa
Mesa and Huntington Beach have been shut down because a suspected cancer-causing
chemical was unknowingly injected into the local water supply, Orange County
Water District officials said Wednesday.
NDMA, or
n-nitrosodimethylamine, is a ubiquitous chemical that occurs naturally, but also
is a byproduct of chlorinating water supplies to disinfect them. It is found in
rocket fuel, pesticides, lubricants, cosmetics and all kinds of food, from bacon
to beer and at far higher levels than turned up in local water tests.
However, with the state beginning to regulate the chemical, water
district officials shut down the wells that exceeded state limits and are
exploring ways to eliminate its presence. The affected wells delivered water
from the aquifer to those cities. There is believed to be no threat to public
health, district officials said.
"Based on testing to date and dilution
at drinking water wells, the water district believes Orange County's ground
water is safe," said William R. Mills, Jr., general manager of the water
district.
NDMA as yet is not regulated by federal or state authorities.
But the state Department of Health Services recently issued temporary guidelines
requiring action if concentrations in drinking water exceed 20 parts per
trillion. That level of exposure is expected to cause one extra cancer case per
million residents who consume two liters of water per day for 70 years.
The water district first discovered the presence of the chemical last
year, when it was testing its underground aquifer for pesticides and herbicides.
At the water district's 200 wells, all met state guidelines in 1999. But last
week, tests at the two wells showed concentrations of 32 to 35 parts per
trillion.
The chemical can be traced to chlorinated waste water used by
the district as a barrier to keep seawater from reaching underground aquifers.
Chlorine, a common disinfectant used to purify water and kill pathogens,
stimulates the chemical reaction that creates NDMA. In late 1999, water in the
seawater intrusion barrier itself averaged 185 parts of NDMA per trillion, just
shy of the state's threshold that would result in mandatory shutdown of the
barrier, said Michael P. Wehner, associate general manager for water science and
technology at the water district.
Levels at nearby monitoring stations
were as high as 150 parts per trillion near the seawater intrusion barrier.
However, Mills said the chemical was diluted as it passed through the aquifer.
Karl Kemp, general manager of Mesa Consolidated Water District, which
operates one of the wells, said his agency is continuing to test the water and
also is exploring ultraviolet devices to destroy the carcinogen.
It's
unknown how long the water supply has been contaminated with NDMA. Technology
that measures such minute particles only became available recently. The chemical
was first found in water in 1998 at an aerospace facility near Sacramento. It
was subsequently found in the San Gabriel Valley ground-water basin. The problem
is probably more widespread; however, California is leading the nation in
monitoring and reducing it. The state Department of Health is conducting a
statewide study to see how widespread the problem is.
"There hasn't been
much looking in other parts of the country," Wehner said.
The water
district has formed a task force with the Orange County Sanitation District, the
provider of the waste water. The agencies are exploring methods to treat and
eliminate the compounds that form NDMA, such as nitrites.
"The best
solution is to find the source," Mills said. "That will take longer."
These findings should not eliminate the use of chlorine as a
disinfectant, said Robert Hultquist, chief of the drinking water technical
operations section of the state health department.
"Chlorine is the most
effective way to control disease-causing microorganisms, such as bacteria,
virus, parasites," he said. "Chlorine eliminates that risk. This is an extremely
helpful chemical."
Officials must balance the risks, he said.
"If we had un-disinfected water, one out of 1,000 people would get sick
every year with potentially life-threatening illnesses," Hultquist said.
However, environmentalists said this discovery reinforces the unknowns
of chlorine disinfection.
"Chlorine clearly over the last century has
been good for public health," said Erik Olson, head of drinking water programs
at the Natural Resources Defense Council's office in Washington. "The one
problem is there is a dark side to the use of chlorine that we've only really
begun to learn about in the last 10 years."
Hundreds of
byproducts are created when chlorine is used
to disinfect water, Olson said, and more than half remain unknown.
"It
is now becoming clear that when you chlorinate drinking water, you create a
toxic alphabet soup of chemicals that can cause cancer and possibly miscarriages
and birth defects," he said, referring to a 1998 study that linked increased
risk of miscarriage with trihalomethanes, a chemical common in chlorinated
drinking water.
"That's the bad news. The good news is we now have the
technology that we can take right off the shelf to largely eliminate the
problems."
There are alternatives such as carbon-filtration or using
ozone or ultraviolet light in place of the chlorine as a primary disinfectant,
he said.
These "were not available 20 to 30 years ago," Olson said.
Water vs. Water
To prevent ocean water from mixing
underground with the drinking water aquifer, the Orange County Water District
injects a barrier of pressurized chlorinated water. A carcinogen associated with
chlorinated water, NDMA, has gotten into the drinking water supply -- forcing
the closure of two wells.
Graphics reporting by BRADY MacDONALD / Los
Angeles Times
GRAPHIC: GRAPHIC: Water vs. Water, RAOUL
RANOA / Los Angeles Times
LOAD-DATE: June 1, 2000