2 February 2003
River Taint Worries Some Officials
Perchlorate, a rocket fuel ingredient, enters Lake Mead near Las
Vegas. California is concerned about its effect on drinking water.
Miguel Bustillo, Times Staff Writer
toxic rocket fuel ingredient that is polluting the Colorado River
-- the main water source for millions of Californians and most of
the nation's winter lettuce -- may be dangerous to public health
even at extremely low levels, state and federal environmental officials
U.S. Environmental Protection Agency and the California Office of
Environmental Health Assessment, which are independently working
to set the nation's first enforceable regulations on ammonium perchlorate,
are concluding from a number of new studies that the substance could
lead to health problems, even in trace amounts.
findings present a serious environmental problem for the Southwestern
United States, because the entire lower Colorado River is polluted
with small amounts of perchlorate from a now-closed Nevada rocket
officials first discovered the contamination five years ago, and
an effort has been underway since then to stem the pollutant's flow
from a desert wash near the factory into Lake Mead. But more than
500 pounds of perchlorate still enters the river system every day,
and it will be years before it is fully flushed out.
one is saying a few glasses of tap water pose an immediate danger.
health scientists say there is an outside risk of developing health
problems from perchlorate, basing their estimates on the assumption
that a person would drink about two liters of the slightly tainted
water each day of a lifetime.
environmental groups say perchlorate's presence in the Colorado
River raises questions about the safety of drinking the river's
water and of eating foods, such as lettuce, that are grown with
are thought to be particularly significant for pregnant women and
babies. Perchlorate is known to affect the production of thyroid
hormones, which are considered critical to brain development, so
fetuses and newborn children may face a greater risk.
more we know about perchlorate, the more concerned we get, because
the science is pointing to low doses affecting brain functions,"
said Gina Solomon, a health expert with the Natural Resources Defense
Council, an environmental group.
kind of things that low to moderate doses of perchlorate might do
include delays in things like language acquisition, motor coordination,"
all, more than 15 million people, including those in the urban expanses
of Las Vegas and much of Southern California, depend on drinking
water from the lower Colorado River. Roughly 15% of California's
water supply comes from the river.
siphoned off to the casinos of Las Vegas contains 10 to 12 parts
per billion of perchlorate, according to officials with the Southern
Nevada Water Authority. Water diverted downstream by the Metropolitan
Water District of Southern California is less polluted, usually
somewhere between 5 and 8 parts per billion. It is subsequently
blended with Northern California water before being piped to Southern
California consumers, reducing its contamination to below detectable
part per billion is roughly equivalent to a grain of sand in an
Olympic-size swimming pool, according to the Metropolitan Water
pollution is an unexpected byproduct of the race to put a man in
space and build bigger and better rockets during the Cold War.
contractors and the Pentagon do not dispute that it can be harmful,
but their interpretation of the data differs from that of environmental
officials. The contractors and military authorities conclude that
the contaminant is dangerous only in higher concentrations.
me make this perfectly clear. We think the concentration in the
Las Vegas Wash is not a health concern for those drinking it,"
said Pat Corbett, director of environmental affairs for Kerr-McGee
Corp., which owns the former perchlorate factory near Henderson,
Nev. The Las Vegas Wash is the desert streambed where the perchlorate
pollution enters Lake Mead in greatest concentration.
the defense industry's own data, however, the federal EPA and California
are arriving at far different conclusions.
EPA has issued a preliminary public health goal of 1 part per billion
for perchlorate -- a number one-seventh the average contamination
now in the lower Colorado River. The number is also one 200th of
what the defense industry says is scientifically sound.
health officials have issued a draft public health goal of 2 to
6 parts per billion for perchlorate. The state expects to establish
new regulations next year; the EPA estimates it will take several
more years to put federal standards in place.
of the studies reviewed by the state and federal environmental officials
were paid for by the military and its contractors, which have been
cooperating for the last five years with the government regulators
in the effort to arrive at new safety standards. But now the two
sides find themselves at odds.
didn't really care" what the number considered safe by regulators
was, "as long as it was based on good science," said Air
Force Lt. Col. Dan Rogers, who has helped lead the military's response
to the perchlorate pollution problem since 1997, and estimates that
the Pentagon, NASA and defense contractors have invested $22 million
some scientists disagree with EPA's interpretation of the data,"
new state and federal perchlorate rules could cost defense contractors
and water agencies tens of millions of dollars, spent to cleanse
waters of pollution. Many of those involved predict that taxpayers
will ultimately foot the bill for a massive cleanup.
central question bearing on the cost is how much risk may come from
eating vegetables irrigated with perchlorate-contaminated water.
More than 1.4 million acres of farmland are irrigated with Colorado
River water, mostly in California's Imperial Valley and the Yuma,
Ariz., area. Together, these areas grow more than 90% of the country's
fresh lettuce during winter months.
data remain limited, some recent studies have suggested that perchlorate
may collect in lettuce at higher concentrations than it does in
the water used to grow the plants, adding to the concern about perchlorate
in the river.
know perchlorate can attain high concentrations in plants -- we
know that," said Phil Smith, a toxicologist at Texas Tech University
who is conducting a study on perchlorate in plants for the U.S.
Department of Agriculture. What remains unclear, Smith said, is
whether perchlorate consumed by eating vegetables has the same effect
on people and animals as perchlorate in drinking water.
industry officials contend it is scientifically premature to conclude
that perchlorate concentrates in plants. They say other research
has even shown that some plants can naturally break down perchlorate
over time. They argue that a 1999 EPA test of lettuce seedlings
that found high concentrations of perchlorate in the seedlings had
been discounted by some scientists because of the testing methods.
The EPA is conducting a second lettuce study and expects to release
its findings within weeks.
perchlorate is shown to collect in vegetables and affect people
who eat them, the finding would have significant consequences.
would mean that the problem of perchlorate is not confined to people
in the West who rely on this drinking water, but the entire nation,
which is eating this lettuce in the winter months," said Bill
Walker of the Environmental Working Group, an organization that
has sounded an alarm about perchlorate for several years and is
now doing its own lettuce tests.
addition to the Colorado River, the EPA has identified roughly 75
perchlorate pollution sites around the country.
California, the San Gabriel Valley, the Inland Empire and the Rancho
Cordova area near Sacramento are all struggling to address perchlorate
pollution. In all three places, dozens of residents near the polluted
sites have alleged they developed health ailments -- including thyroid
problems and cancer -- from exposure to perchlorate. The state Department
of Health Services is studying whether there is an increase in thyroid
problems near those areas.
perchlorate had been a public concern for years, it was not until
1997 that the magnitude of the problem became clear. That year,
California health officials developed a new method to detect the
pollutant at levels far lower than previously possible, and water
officials discovered to their surprise that contamination was far
more widespread than first believed.
Metropolitan Water District of Southern California, the area's primary
urban wholesaler, soon detected perchlorate deep in its massive
Colorado River Aqueduct, which pipes water 240 miles into Riverside
County. It performed further tests and found that pollution levels
increased as testing moved upstream. The sleuthing eventually pinned
down the source of the contamination as the Las Vegas Wash, a formerly
seasonal stream that now flows year-round with the treated waste
water of Las Vegas. Tests further up the stream found no perchlorate.
discovery quickly triggered a response from the EPA, the Nevada
Division of Environmental Protection and Kerr-McGee, which owned
a nearby perchlorate plant that for years dumped tons of the rocket
fuel oxidizer directly into unlined lagoons.
plant, which Kerr-McGee acquired through a merger in the late 1960s,
was first converted to perchlorate manufacturing by the Navy after
World War II. It was closed in 1998, when Kerr-McGee got out of
the perchlorate business.
current cleanup, overseen by Nevada and funded by the company, started
in 1998 and is showing signs of success, according to state, EPA
officials and the defense contractor.
isolated an underground stream that was carrying perchlorate pollution,
and are now running 34 wells to pump out the ground water before
it reaches the Las Vegas Wash.
a result, the contamination spilling into the wash has dropped from
an average of 900 to 1,000 pounds per day to 500 to 550 pounds,
and recent gains suggest the numbers could go down dramatically
in coming months, said Todd Croft, the Nevada official in charge
of the cleanup.
Lake Mead of perchlorate, however, is a far more complicated matter.
EPA officials speculate it could take decades to fully wash out,
even after the stream polluting it is cleaned up.
Mead is a complex reservoir," said Kevin Mayer, the EPA's point
man on perchlorate. "It is not going to flush like a bathtub."