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Winter lettuce crops in California are contaminated with
perchlorate, a component of rocket fuel, which can harm humans,
especially infants and developing fetuses, according to a
study.
Exposure to perchlorate, which is highly water-soluble, can
cause mental retardation, loss of hearing and speech, and
motor skill deficits in developing fetuses. The compound is
a known contaminate of drinking water in 20 states and also
contaminates the Colorado River, which irrigates 70 percent
of the United States’ winter lettuce supply, according
to the study.
In the study, researchers analyzed 22 commercial lettuce
samples, including prepackaged and head lettuces, adult and
baby greens, and organic and conventionally grown.
Four of the 22 samples tested contained perchlorate in excess
of 30 parts per billion (ppb). The highest sample, mixed organic
baby greens, had 121 ppb. In 2002, the Environmental Protection
Agency found that perchlorate in drinking water poses health
risks in concentrations above one part per billion.
Based on those results, the study researchers concluded that
1.6 million U.S. women of childbearing age are exposed each
day to levels of perchlorate above the EPA's recommended safe
dose from winter crops of lettuce alone.
According to the study, lettuce, which is being sold in U.S.
supermarkets, absorbs and concentrates significant amounts
of perchlorate from polluted irrigation water.
Moreover, close to 90 percent of the U.S. winter lettuce
supply is grown in Southern California and Arizona with irrigation
water from the Colorado River, which is contaminated with
perchlorate.
However, several groups have come out against the EPA’s
recommendation, including the Pentagon and several defense
contractors, who could be responsible for billions of dollars
in potential cleanup liability for perchlorate pollution,
arguing that perchlorate is safe in drinking water in quantities
70 to 200 times greater than the EPA’s recommended safe
dose.
Definitive data on the levels of perchlorate in U.S. produce
was supposed to have been available years ago, however, the
Defense Department reportedly would not fund the estimated
$215,000 needed to collect samples of vegetables, leading
some environmentalists to question whether the Defense Department
really wanted to know if perchlorate was contaminating food.
According to one environmental scientist, "If they can
spend $1 million on a cruise missile, it seems kind of ridiculous
they won't spend $200,000 to see if our food is contaminated
with rocket fuel."
Researchers of the current study say that their results are
not conclusive due to their small sample size. However, they
hope that their results will spur the federal government to
conduct a more definitive study that will take a comprehensive
look at the potentially widespread perchlorate contamination.
Wall
Street Journal April 28, 2003
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