Examples: Chlorpyrifos (Dursban), Methyl
Parathion
Known Health Effects: Neurotoxic. Vomiting, diarrhea, abdominal
cramps, dizziness, eye pain, blurred vision, confusion, numbness,
twitching, paralysis, death.
Suspected Health Effects: Brain, nervous system damage. Endocrine
disrupter. Liver, respiratory system toxicant. Birth defects, childhood
brain tumors, leukemia and lymphomas.
The organophosphate pesticides are a family of home and agricultural
bug killers, most of them in use for decades, that are at the top
of the Environmental Protection Agency's priority list in the wake
of a 1996 pesticide reform law aimed at protecting children. The agency
recently took action against both methyl parathion banning
its use on some children's food and Dursban (chlorpyrifos)
- which was banned for all home and garden uses.
Soon after exposure to organophosphate pesticides, the human body
converts the chemicals into altered forms called metabolites. Two
organophosphate metabolites turned up in the test of Bill Moyers
urine. Of the five most likely pesticides he could have been exposed
to, one is for home use pest strips and bug sprays; the other
four are used as pesticides on food crops.
Originally, organophosphates were developed as nerve-gas agents for
chemical warfare. They work by paralyzing muscles, and in large amounts
they can kill humans and other species in the same way that they kill
bugs.
According to the EPA, all organophosphates are toxic to the nervous
system. They can interfere with vision, learning and memory. Chronic
exposure may lead to disorientation, severe depression, irritability,
confusion, headache, speech difficulties, delayed reaction times,
nightmares, sleepwalking and drowsiness or insomnia, as well as numbness,
cramping and weakness in the legs. In higher doses, people may suffer
from vomiting, diarrhea, abdominal cramps, dizziness, eye pain, blurred
vision, slurred speech, loss of reflexes, twitching, tremors of the
tongue or eyelids, and eventually, paralysis of the body extremities
and the respiratory muscles. The pesticides may also cause liver problems
and stomach inflammation.
Young children may be especially vulnerable. According to the National
Academy of Sciences, if exposure to these neurotoxic compounds occurs
during the prenatal and early childhood period of brain development
it could result in permanent loss of brain function, even
at exposure levels believed to be safe for adults. Several studies
have also linked early exposures with childhood brain tumors, leukemia,
and lymphomas, as well as increases in birth defects.
Chlorpyrifos sold under the trade name, Dursban - is an insecticide
which was widely used in homes and on farms. On the farm, it is used
to control ticks on cattle and as a spray to control crop pests. In
the home, it is used to control roaches, fleas, and termites; it is
also used in some pet flea and tick collars. It was the bug spray
of choice for home exterminators for the past 30 years. The manufacturer
estimates that chlorpyrifos has been sprayed in and around an estimated
20 million American homes every year. Now, researchers have discovered
that much of this toxic pesticide winds up on childrens toys.
After pesticides are sprayed in the home, they evaporate from floors,
carpets and drapes, and then re-condense on toys and pillows. In 1998,
scientists at Rutgers University found that plastic and plush toys
somehow attracted the pesticides more than other objects. Since young
children spend a lot of time putting things in their mouths, contaminated
toys are likely to give them much higher doses of poison than adults
would get in the same environment.
Under the EPAs agreement with pesticide makers, Dursban will
stay on store shelves until the end of 2001, so many home supply stores
are still selling Dursban products, often with the prices slashed
by 50 per cent.
EPA also discovered that children frequently are exposed to heavy
doses of orgahophosphates in foods such as apples, peaches, pears,
plums, cherries, grapes, berries, carrots, peas, and spinach. Before
EPA restricted the use of methyl parathion on those crops in 2000,
the agency calculated that children were consuming eight times more
of this one pesticide than EPA considered safe. Methyl parathion is
still used on cotton, corn, wheat, nuts, cabbage, hops, lentils, oats,
onions, rice, soybeans, beets, sunflowers, potatoes and other crops.
In 1998, growers sprayed 4.2 million pounds of methyl parathion over
4.9 million acres.
pdf
- EPA Human Health Risk Assessment for Methyl Parathion
pdf
- EPA Hazard Assessment of Organophosphate Pesticides
Full list of sources available via e-mail
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Organophosphates work by paralyzing muscles, and in large amounts
they can kill humans and other species in the same way that they kill
bugs.
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