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PRI's Environmental News Magazine

Organophospates

Air Date: Week of October 3, 1997

Every year, the U-S uses more than a billion pounds of pesiticides to exterminate rodents and insects, weed our lawns and protect crops. Recent research on one class of insecticides -- organophosphates -- may lead to restrictions on their use. LOE’s Daniel Grossman reports from a Washington state orchard.

Transcript

KNOY: It's Living on Earth. I'm Laura Knoy. Each year Americans use more than 1 billion pounds of pesticides. We exterminate rodents and insects, keep our lawns weed-free, and protect our crops. Some of these chemicals are safer than others, but researchers are now beginning to assemble a powerful indictment against one class of insecticide, organophosphates. And pressure is building to dramatically restrict their use. Living on Earth's Daniel Grossman visited Washington State, where organophosphates are widely sprayed in orchards. He has this report.

(The sound of keys, a car motor being started)

GROSSMAN: Gip Redman navigates his pickup truck down a bumpy lane through trees heavy with ripe, colorful fruit. He owns a good-sized orchard here in the Yakima Valley, one of the nation's largest fruit-growing regions.

REDMAN: This is a solid block of goldens. Peaches in the next orchard, flame cress variety. We're harvesting those.

GROSSMAN: With the harvest in full swing, migrant workers are busy picking peaches, nectarines, plums, and pears. It's like Eden's own orchard. And the serpent in this garden is the coddling moth.

REDMAN: If unchecked, they can grow and multiply to such an alarming rate that they in fact would put a hole in each fruit. At least one.

GROSSMAN: The coddling moth is the most serious foe, but many pests attack fruit here, including aphids and mites. Gip Redman says he uses a variety of strategies to protect his crops, like spraying oil on spring buds. But his chief weapon is pesticides. Fruit trees are among the most sprayed crop in agriculture, and it's easy to spot signs of pesticides in Gip Redman's orchard.

REDMAN: There's one of the signs of a block that we've sprayed. It says, "Do not enter." "Entrada prohibit." "Peligro." "Danger."

(A car door closes. A tractor motor revs up.)

GROSSMAN: In a nearby orchard a tractor ambles between rows of pear trees. Its driver wears a white jumpsuit and a protective mask. Spewing from behind his rig, a chemical called guthion rises in a mist above the treetops and settles back down on the leaves and fruit. Guthion is one of the most toxic pesticides produced. Four years ago, Moddy Schicker was sprayed with the chemical during a harvest.

SCHICKER: We were picking pears about 9, 9:15, and you could hear a tractor. Well, you hear tractors in the fields all the time, so we didn't pay a lot of attention to it. Tractor driver waved at one of the workers that was over closer. And I thought well, you know, I've seen them spray before but, you know, it was never nothing harmful. And he went down the road and then he made this turn and he come back and he sprayed again. Well by then, the wind was bringing it in our direction. And I'd say by 9:15, 9:30, your skin was burning, the eyes were burning. You could taste it, very bitter quinine taste in your mouth.

GROSSMAN: After work Moddy Schicker went home, washed up, and went to bed.

SCHICKER: Next day I got up and my face looked like somebody had stuck boiling water into it. I went to my family doctor and he told my mom, he said, "You put this salve on her face twice today. Wrap her in this clear, cling-free wrap." And she had to pack my face in ice. And I could not go outside the house for 2 weeks straight. Then when I went out, I had to wear dark glasses.

GROSSMAN: Public health officials say each year as many as 20,000 farm workers in the US and about 1 million worldwide are poisoned with pesticides. Many of these accidents involve guthion and other organophosphates, the most common class of chemical used to control insects. Organophosphates come from the same family as the deadly nerve agents in the US chemical weapons stockpile, although they're considerably less potent. They were formulated early in this century, but didn't come into widespread use until the 1960s, after organochlorines like DDT came under attack. Today in the United States, 79 million pounds of organophosphates are sprayed on crops and in homes and businesses. A recent study by the US Centers for Disease Control found the byproducts of chlorpyrifos, the most common organophosphate, in the urine of 80% of Americans surveyed. It's likely that every American is exposed to one or more of these chemicals in food and drinking water, in fumes from roach and termite treatments. The good news is, organophosphates break down fairly quickly after being sprayed. The bad news is...

KIEFER: When you get overdosed with organophosphate pesticides, what happens is you suffer a sort of a glandular crisis.

GROSSMAN: Matthew Kiefer is a doctor of occupational medicine at Seattle's Harborview Medical Center. He says organophosphates poison humans by disrupting the nervous system.

KIEFER: Your salivary glands secrete. Your tears secrete. Your bronchial glands secrete. The whole system that drives those glands basically starts, goes into overdrive. The same system controls the contraction of muscles. And as a result, you overstimluate the muscles. And with certain pesticides, they can enter into the brain and depress the centers that drive respiration. And if the case is severe enough you can actually have a person stop breathing, and sometimes they'll die.

GROSSMAN: It was once accepted that people surviving such events recovered fully. Now many researchers have their doubts. Dr. Kiefer is an author of one of the studies turning the tide.

KIEFER: The data that's been collected to date supports the fact that people just don't get quite back to their baseline after they've suffered an acute intoxication. The effects seem to be subtle, but they're there.

GROSSMAN: Subtle, but serious. Dr. Kiefer's study shows that poison victims suffer long-term and possibly permanent deficits, including decreased reasoning power, impaired speech, and memory loss. These conclusions don't surprise Moddy Schicker, who says she has still not recovered from being sprayed in 1993.

SCHICKER: You lose your concentration real quick after you've been sprayed with pesticide. Things that you used to do, you don't do no more. I mean, I was one that was outdoors all the time, I done crafts all the time, and you just -- it just -- you lose all interest. Actually, it turns your whole life upside-down.

(Clanking on metal; a farm worker sings in Spanish)

GROSSMAN: Pulling down a branch from a pear tree, Abito Rodriguez gently snaps the fruit from its green stems. These trees he's picking were last sprayed with guthion and other pesticides about 6 weeks ago. Federal law permits workers to re-enter orchards just hours after fruit is sprayed with these chemicals, and researchers have detected organophosphate byproducts in the urine of workers who've been kept out of sprayed orchards for as much as a month. Some health experts say laborers like Mr. Rodriguez, with no apparent signs of poisoning, could be in danger from cumulative exposure to such pesticides. Consumers of fruit and residents of homes treated for pests could also be at risk. Dr. Matthew Kiefer hopes to get some answers with a study he's completing of Yakima Valley farm workers.

KIEFER: We do know that the population in the United States does have exposure to organophosphate pesticides on a routine basis, both in very low levels in food and sometimes in house, pesticides that have been applied in the house. And so, if we find abnormalities in these populations who have much higher exposure than that, we may have something to say about people with lower-level exposure, or at least may motivate further study.

GROSSMAN: The evidence so far is inconclusive. One British study found that farmers suffered impaired reasoning power and other psychological deficits after treating sheep with organophosphate dips. Other occupational studies have come up empty-handed. Meanwhile, research on animals has found that some organophosphates interfere with the systems that regulate reproduction, growth, and development, raising additional concerns.

WARGO: If we can't prove safety in the very near term, we should revoke the licenses.

GROSSMAN: Dr. John Wargo is a professor of environmental policy at Yale University and author of the book Our Children's Toxic Legacy. He's among a growing number of health experts who say it's time to severely restrict or even ban this class of insecticides.

WARGO: We don't have enough evidence to demonstrate that the organophosphates are safe. We have substantial evidence that demonstrates that they pose significant risks. And from my perspective, the way that we should approach the uncertainty in the evidence is to be cautious.

McCARTHY: These products are important, and they're used with care.

GROSSMAN: Thomas McCarthy is a top official with the American Crop Protection Association, which represents pesticide manufacturers. He says banning organophosphates would jeopardize the nation's food supply and would not be supported by scientific evidence.

McCARTHY: There's a tremendous amount of information that's been developed on these over the years. There's been epidemiology information, good toxicology information. There's been surveillance of what kind of residues are in our food, in our water. It just all adds up to say it's safe.

GROSSMAN: But the US Environmental Protection Agency is far from convinced these chemicals are safe. It's reviewing the entire class of organophosphate insecticides in the first test of the year-old Food Quality Protection Act. Unlike previous acts, this new law instructs the Agency to estimate the total exposure individuals receive from all sources, and to take into account exposures to related pesticides. And it says regulations must protect even the most sensitive individuals, like children and pregnant women. The EPA is expected to issue new rules on organophosphates by mid-1999. For Living on Earth, I'm Daniel Grossman.

 

 

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