28 April 2003
Samples Found Tainted
Conclusions on perchlorate are elusive, but environmental group
calls for action.
laboratory test of 22 types of lettuce purchased at Northern California
supermarkets found that four were contaminated with perchlorate,
a toxic rocket-fuel ingredient that has polluted the Colorado River,
the source of the water used to grow most of the nation's winter
environmental group that paid for the testing by Texas Tech University
conceded that the sample was far too small to draw definite conclusions
about how much perchlorate is in the lettuce Americans eat. But
the organization, the Environmental Working Group, said the results
were alarming enough to warrant a broad examination by the Food
and Drug Administration.
appears perchlorate in produce is reaching consumers, which should
be a wake-up call for the FDA," said Bill Walker, a western
representative in the group's Oakland office. "A lot of people
might look at this and say it was only four out of 22 — what
is the problem? Well, when nearly one in five samples of a common
produce item are contaminated with a chemical component of rocket
fuel, that's significant."
response, FDA officials said they had been planning to begin testing
foods for perchlorate at a number of sites across the country, but
were still developing the scientific methods to do it.
do understand that there is a potential for perchlorate from irrigation
water to end up in food," said Terry Troxell, the director
of the FDA's office of plant and dairy foods and beverages. "We
have already been moving in this area. We will certainly take their
results into account."
four lettuce samples all contained substantial quantities of perchlorate.
One, a packaged variety of organic mixed baby greens, had a level
of perchlorate contamination at least 20 times as high as the amount
California considers safe for drinking water. The other three were
packaged butter lettuce and radicchio, romaine lettuce and radicchio
and a head of iceberg lettuce. All were at least five times as high
as the state considers safe for water.
and federal environmental officials believe that perchlorate, a
salt widely used by the U.S. government to help power missiles and
the space shuttle, may cause health problems, even in trace amounts.
Because it is known to affect the production of thyroid hormones,
which are critical to early brain development, researchers believe
perchlorate exposure may be especially dangerous for pregnant women
and young children.
the Pentagon and defense contractors, who together produced most
of the nation's perchlorate, dispute those conclusions, saying their
scientists believe it poses a health threat only in doses dozens
of times higher.
state or federal agency has set any enforceable health standards
for perchlorate in water and food. But several are developing them,
including the California Department of Health Services and the U.S.
Environmental Protection Agency.
groups, which note that the perchlorate in produce is believed to
come from the water that farmers use to irrigate crops, not from
pesticides, urged swift government action.
is a problem. It's not one we created, but it's one we are concerned
about. We want the leading regulatory agencies to address this problem
as soon as possible," said Hank Giclas, a vice president of
the Western Growers Assn., whose members grow, pack and ship 90%
of the fresh vegetables and 70% of the fresh fruit and nuts in California
and Arizona. "In the meantime, we want people to continue eating
fruits and vegetables.''
EPA declined to make its perchlorate experts available to discuss
the Environmental Working Group's findings, which they were permitted
to review. A statement released by the agency's headquarters said
that the EPA would not make additional comment on the contaminant
until the National Academy of Sciences completes an independent
peer review it is conducting of EPA's work to date on perchlorate
and human health.
has become a volatile political issue in recent months. Democrats
have accused the military of foot dragging and have demanded faster
federal action; Republicans have called for further scientific research
and cautioned against a rush to judgment.
Sens. Dianne Feinstein and Barbara Boxer of California and Harry
Reid of Nevada wrote Defense Secretary Donald H. Rumsfeld earlier
this month and asked the Department of Defense to "take a more
aggressive and positive role" in cleanup efforts. They noted
that "nearly all the perchlorate produced in the United States
over the last half century was used by the department and our space
the same time, a Bush administration proposal known as the Readiness
and Range Preservation Initiative is making its way through the
GOP-controlled Congress. Among other things, it would exempt military
bases from laws requiring the cleanup of toxic substances associated
with munitions and other explosives, which include perchlorate.
nationwide price tag of perchlorate cleanup could be in the tens
of millions, and possibly even billions, of dollars, according to
water officials and other experts, who say it has the potential
to dwarf California's problems with MTBE, a gasoline additive that
tainted groundwater supplies. Perchlorate, which is highly soluble,
has been detected in water supplies in California and at least 19
other states, usually near defense contractors or military bases.
The Colorado River, which supplies drinking water to about 15 million
people in the Southwestern United States, contains perchlorate that
leached from the site of a former Nevada rocket fuel factory.
groups have warned that perchlorate may also be widely present in
vegetables, because countless crops are irrigated with water from
the same tainted sources.
have been only a few limited studies on perchlorate and plants so
far, including an EPA study of lettuce seedlings and a 1997 study
of lettuce grown in the San Bernardino area by Lucky Farms. They
suggest the substance may concentrate in plants. But industry groups
have questioned the results, noting that the government has yet
to establish a standardized system for testing perchlorate in plants,
as it has done with testing in water.
a lot more difficult to test in plants than in water," said
Dr. John Gibbs, medical director for Kerr-McGee Corp., owner of
the former Nevada perchlorate factory that has contaminated the
said it was important to determine how the lettuce was grown, because
some fertilizers contain perchlorate.
Anderson, a professor of environmental toxicology at Texas Tech
who conducted the lab tests, said they reflected a conservative
estimate of the amount of perchlorate in the lettuce. If anything,
Anderson said, more of the 22 lettuce samples might have contained
some perchlorate, because the test method used could detect the
contaminant only at levels 10 times as high as the tests used to
measure perchlorate in water.
are very confident in this data," Anderson said.
EPA and the California Office of Environmental Health Hazard Assessment
are working independently to set the nation's first enforceable
standards on perchlorate.
officials have released a preliminary public health goal of two
to six parts per billion for perchlorate in water. The EPA disclosed
a draft number of one part per billion, but later clarified that
it was premature.
lower Colorado River is somewhere from five to eight parts per billion
perchlorate as it flows through the fertile farm country of Arizona
and California, where 70% of the nation's winter lettuce is grown
from October to March.
four types of lettuce that tested positive in the Environmental
Working Group sample all had at least 30 to 40 parts per billion
perchlorate. The organic lettuce registered 120 parts per billion.
One part per billion is roughly equivalent to a drop of water in
a residential swimming pool.
Environmental Working Group declined to disclose the brands of lettuce
that contained contamination, or where they had been purchased,
saying it was wary of triggering a food scare.
it said it had bought the lettuce at supermarkets in Northern California
in January, when about 88% of the nation's lettuce comes from farms
nourished with water from the Colorado River.