| Lettuce
and other vegetables grown in fields irrigated by the Colorado
River may contain higher amounts of toxic rocket fuel than is
considered safe by the U.S. Environmental Protection Agency
(EPA).
Leafy green vegetables grown with contaminated water store
and concentrate potentially harmful levels of perchlorate,
a thyroid toxin that is a main ingredient of rocket and missile
fuel, according to tests.
Further, aerospace and defense contractor Lockheed Martin,
a major user of perchlorate, reportedly knew as early as 1997
that vegetables stored high concentrations of the chemical,
but did not release the information to health officials. There
is also speculation that the Department of Defense may also
have known, but did not warn other agencies, farmers or consumers.
Analysts recommend that the Food and Drug Administration
(FDA) begin testing on vegetables grown with water from the
Colorado River, and, if harmful perchlorate levels are confirmed,
take immediate action to reduce contamination and keep the
food off the market.
Additionally, farmers who are adversely affected by perchlorate
contamination of their crops should be fully compensated for
all economic losses.
Perchlorate has contaminated close to 300 drinking water
sources and farm wells in California and an unknown number
of sources in at least 15 other states. The chemical impairs
the thyroid’s ability to take up iodide and produce hormones
that are critical to proper fetal and infant brain development.
The EPA doesn’t plan to adopt national standards for
perchlorate in drinking water until at least 2006, although
elected officials in California are calling for faster federal
action.
However, it appears that vegetables grown with perchlorate-contaminated
water may pose more of a threat than drinking water.
According to a 1999 study of lettuce seedlings grown in perchlorate-contaminated
water, perchlorate was accumulated in the leaves by factors
of 100 times or more. The lettuce was able to take up and
store 95 percent of the perchlorate in the water, which means
that lettuce grown in water with even low levels of perchlorate
could deliver doses far higher than the EPA’s provisional
drinking water standard.
Despite preliminary research that suggests food is likely
to be an equal or greater source for perchlorate exposure
than drinking water, this hasn’t been reflected in the
proposed drinking water standards, which would need to be
substantially lower to account for the exposure coming from
food.
Environmental
Working Group June, 2003
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