- EVANSTON, Ill. --- Chicago
has one of the highest rates of lead poisoning in the United States, an
extremely persistent health problem that particularly plagues urban areas.
Now a new study by Northwestern University researchers shows that edible
plants grown in urban gardens could contain potentially hazardous amounts
of lead.
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- Kimberly A. Gray, associate professor of civil and environmental
engineering at Northwestern University, and her team tested a variety of
plants cultivated in Chicago residential gardens rich with lead-contaminated
soil. They found that leafy vegetables and herbs were highly likely to
also be contaminated with lead.
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- The findings were published online by The Science of
the Total Environment and will appear in an upcoming print issue of the
journal.
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- The researchers harvested fruiting plants, leafy greens,
herbs and root vegetables from 17 gardens, washed and dried the plants,
and then separated root, shoot and fruit before analyzing them for lead
content.
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- While the majority of the lead was concentrated in the
roots, some lead was detected in shoots, which is often the portion of
the plant that people eat. Gray's team calculated what amount of lead would
be ingested by consuming some of the herbs such as cilantro. They found
that those levels exceeded what would be excreted in children or women,
which means lead would be stored in the body. These findings are very important
for children and women of childbearing age.
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- "We are concerned about the edible portions of leafy
vegetables and herbs that were found to contain lead," said Gray.
"It is important that urban gardeners locate fruit and vegetable gardens
away from buildings, test the lead levels in their soils and develop strategies
to ensure safety for them and their children."
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- The lead concentration in the fruit of other plants,
such as strawberries and tomatoes, was not found to be hazardous. Root
vegetables, such as carrots and onions, are likely to have high levels
of lead, but the very small sample size did not allow the researchers to
draw a conclusion about this group.
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- Much of the soil's lead contamination comes from deteriorated
paint, past use of lead-containing gasoline and industrial air pollution.
Lead in soil does not biodegrade or decay.
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- The study grew out of an earlier federally funded, two-year
phytoremediation project in Chicago's West Town community in which Gray
and colleagues wanted to see if green plants could remove lead from contaminated
soil or, at a minimum, stabilize the lead in the soil to reduce exposure
of humans and animals to the toxin.
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- Other authors on the paper are Mary E. Finster, a Northwestern
University graduate student working with Gray, and Helen Binns, M.D., an
associate professor of pediatrics at Northwestern's Feinberg School of
Medicine.
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- http://www.eurekalert.org/pub_releases/2003-11/nu-eup112103.php
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