Wednesday November 11, 2008 (foodconsumer.org) -- A new
study suggests that pesticides can pose a serious threat to the environment and
possibly human health when used in combination in agricultural products at even
levels the EPA allows although they may not cause any harm when used
The study led by researchers from the University of
Pittsburgh found that concentrations of 10 most commonly used pesticides that fell
within EPA safe-exposure levels when combined killed 99 percent leopard frog
Amphibian populations have been on the decline while the number
of deformed frogs has been seen to increase in states like Illinois and Pennsylvania.
For the study published Nov. 11 in the online edition of
"Oecologia", Rick Relyea and colleagues tested five
insecticides-carbaryl, chlorpyrifos, diazinon, endosulfan, and malathion-and
five herbicides-acetochlor, atrazine, glyphosate, metolachlor, and 2,4-D in
The researchers found a mixture of all 10 chemicals
killed 99 percent of leopard frog tadpoles as did the insecticide only mixture.
The herbicide mix had no effect on the tadpoles.
They also found that Endosulfan - a neurotoxin banned in
several nations but still used extensively in the U.S. agriculture - was more
deadly to leopard frog tadpoles than previous thought. This pesticide when used
alone killed 84 percent of the leopard frogs.
The findings are alarming because current regulations
from the U.S. Environmental Protection Agency (EPA) did not require amphibian
testing, Relyea said.
This chemical is
most lethal among the tested pesticides.
"Endosulfan appears to be about 1,000-times more
lethal to amphibians than other pesticides that we have examined," Relyea
said. "Unfortunately, pesticide regulations do not require amphibian
testing, so very little is known about endosulfan's impact on amphibians,
despite being sprayed in the environment for more than five decades."
For most of the pesticides, the concentration used in the
study was far below the human-lifetime-exposure levels set by the EPA and also
fell short of the maximum concentrations found in natural bodies of water.
The study suggests that the potential harm by pesticides
should be considered when they are used in combination, but not individually.
Many people may not know this, but multiple pesticides
have already been detected in many types of fruits and vegetables.
According to the Environmental Working Group, the data
from the US government show that apple can contain more than 30 types of
Although, the pesticides individually
may not pose too much of a risk, the risk from these pesticides in combination remain
Those who want to avoid as much as of pesticides may want
to consider avoiding certain produce. The conventionally grown fruits and
vegetables that contain highest levels of pesticides include peaches, apples,
sweet bell peppers, celery, nectarines, strawberries, cherries, lettuce,
imported grapes, pears, spinach, potatoes, carrots, green beans, hot peppers,
cucumbers, raspberries, plums, oranges, and domestic grapes according to the
But the fruits and vegetables with lowest concentrations
of pesticides include
broccoli, eggplant, cabbage, banana, kiwi,
asparagus, sweet peas (frozen), mango, pineapple, sweet corn (frozen), avocado
and onion, according to
foodnews.org, a website of the EWG.
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