"The Trouble with Carbaryl" - Organic Gardening, October 1984 [see 1993 article]
- symptoms of carbaryl poisoning
- stillbirths, birth defects, and sterility
- forms a potent carcinogen in the human stomach
- readily and completely absorbed through human skin
- irreversible effects on children
- children should not be allowed in a sprayed area for 40 days
- persists in the soil for many months
- no acceptable intake level
"The Trouble with Carbaryl
Six dangers the pesticide label won't warn you about."
By Warren Schultz Jr.
[click here for page 1: history of carbaryl. Below is page 2, about the dangers:]
You won't find the following precautions on any carbaryl containers. The EPA doesn't require these warnings. But we think they belong there.
May Be Fatal If Swallowed. In its literature, Union Carbide maintains that there have been no documented accidental fatalities due to carbaryl exposure. That's true as far as it goes. But that's not to say that carbaryl has never killed anybody. There have been at least four recorded suicides caused by ingestion of carbaryl.. In addition, according to the EPA's most recent information, the Pesticide Incident Monitoring System shows a dramatic increase in the number of nonfatal poisonings in recent. From 1966 through 1971 these were fewer than 10 recorded incidents each year. In 1972 and 1974 there were less than 50. But in 1973 and 1975 there were between 50 and 100 incidents, and in 1976 and 1978 there were more than 100 poisonings each year.
Symptoms may include violent stomach pain, excessive sweating, vomiting, blurred vision, severe weakness and light-headedness. Symptoms have been observed with the ingestion of as little as ¼ gram of pure carbaryl.
May Cause Birth Defects. "Women of Childbearing Age Should Not Be Involved in the Mixing, Loading, or Application of Carbaryl. Exposure to Carbaryl During Pregnancy Should be Avoided" - was the label change recommended to the EPA by a Special Subcommittee of the Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel. The committee based its recommendation on what it called "clearly defined teratogenic effects shown by carbaryl at relatively low doses when fed to beagle dogs " In two experiments, one of them conducted by Union Carbide, pregnant dogs were administered carbaryl at doses ranging from 3 to 50 milligrams per kilogram of body weight per day throughout the gestation period. In the first experiment, birth defects were seen in 11.6% of the pups compared to zero in the control group. The second experiment also resulted in stillbirths and defects. However, the EPA determined that the studies were flawed. In 1984 they ordered a repeat of the experiments and a new precautionary statement. Sevin products used for flea control on animals must now bear the warning: "Do not use this product on pregnant dogs."
May Cause Sterility in Men. Erik Jannson from Friends of the Earth reports that the sharp increase in sterility in American males appears to be caused primarily by exposure to hazardous substances. Jannson believes that Sevin is one of the culprits. He cites a 1980 study of carbaryl plant employees in which 14.9% of the workers had depressed sperm counts and were functionally sterile, compared to only 5.5% in a control group. A second study showed "a significant elevation of sperm abnormalities" as compared to a control.
Jannson points out that most birth defects are now male related, caused by sperm abnormalities. Extremely low sperm counts such as found in carbaryl workers not only cause sterility, but they're also related to higher birth-defect rates.
May Form Carcinogens. Carbaryl itself is not carcinogenic. Nitroso carbaryl is. Dr. William Lijinsky, director of the Chemical Carcinogenesis Program for the National Cancer Institute in Maryland says that nitroso carbaryl is among the most potent carcinogens known. In an affidavit, Dr. Lijinsky states that "Nitroso carbaryl, in my opinion, is readily formed in the human stomach when carbaryl residues combine chemically with nitrites." He points out that nitrites are found in cured meats and fish, frankfurters, bacon, ham and bologna. But even if you never eat any of those foods, nitrites are naturally present in human saliva.
Dr. Lijinsky says he is especially concerned about aerial spraying of carbaryl and the exposure of children to the residues.
Danger: Do Not Allow Children Near Areas Treated with Carbaryl. Dr. Ruth Shearer, a molecular geneticist, is also alarmed about the widespread use of carbaryl, especially aerial sprayings aimed against gypsy moths. She believes that a significant danger to children comes from dermal exposures. "Carbaryl is rapidly and nearly completely absorbed through human skin," she warns. Using World Health Organization figures, she calculated that children are endangered whenever carbaryl is sprayed over wide areas. The WHO has set an Acceptable Daily Intake (ADI) of carbaryl for humans at 0.01 milligrams per kilogram - that equals 1- billionths of our body weight. The intake can be oral, dermal or respiratory. For example, she says, a proposed aerial spraying of one pound of Sevin per acre (that's 10.4 milligrams per square foot) would mean that a 33-pound child would exceed his ADI if he touched more than 2 square inches of soil, table, bench or foliage in the spray area on the day of the spraying. Even a week later, he could safely touch only 4 square inches per day.
Actually, very little is known about the effects of pesticides on children. But a 1979 report by Clement Associates Inc. for the U.S. Department of Labor warns: "It is scientifically safe to assume that children may be more susceptible than adults to certain irreversible toxic effects, such as carcinogenesis and mutagenesis, and to irreversible effects on reproduction and neurophysiology."
Clement Associates was hired by the labor department to study pesticide persistence and recommend reentry levels for farm workers. That is, the time limit for safe entry into a field after it has been treated with a pesticide. Specifically, Clement's assignment was to recommend standards for reentry intervals for 10- and 11-year-old children harvesting strawberries and potatoes that had been treated with carbaryl. Their conclusion: Where carbaryl is applied at recommended rates (2 pounds per acre for strawberries and one pound per acre for potatoes, or 20.8 and 10.4 milligrams per square foot), children should not be allowed back in the fields for 40 days.
Warning: Residues May Vary In Persistence. The label of a carbaryl container lists the crops on which it may be used and preharvest intervals -- how long the gardener must wait between applying the pesticide and eating the crop. The information about application rates is less specific. It may say "dust lightly," or "thoroughly cover leaves," and "repeat as necessary." But even if you clearly follow label directions, you might wind up with an overdose.
Take tomatoes, for example. The label states that carbaryl dust "may be applied up to harvest." That sounds like you could go out into the garden with a canister of Sevin in one hand and a salt shaker in the other. There isn't even a caution to wash the fruit before eating. However, two Indian studies suggest that carbaryl residues may linger longer.
Researchers in India sprayed a tomato crop with a 0.2% carbaryl solution, then harvested the fruit at intervals and checked for residues. It took 25 days for the substance to become completely dissipated. Residues in the fruit picked 5 days after spraying exceeded the maximum tolerance level of five parts per million (ppm), as set by the World Health Organization. Even washing the fruit didn't remove all the pesticides. Tomatoes that contained 10.7 ppm carbaryl on the day of spraying were washed for 2 minutes. After that, the residues in the fruits still measured 4.06 ppm.
The other study showed similar results on cauliflower. The crop was sprayed with 2.5 kg of Sevin 50 wettable powder per hectare, a common rate. The initial deposit of carbaryl on the curds was 16.75 ppm. It took 6 days for the residues to dissipate below the accepted 5 ppm tolerance level. After 15 days there was still a detectable residue on unwashed curds.
Dr. Shearer also warns about the persistence of carbaryl in the soil. According to her, independent studies show that the pesticide has a half-life of 23 to 28 days on dry soil. Therefore, one-eighth of the application would be on the ground almost 3 months later.
WHERE O.G. STANDS
The Environmental Protection Agency is aware of the evidence against carbaryl. But they maintain that some of the tests were flawed, that "data gaps" exist concerning the risks of the pesticide, and that carbaryl is safe enough to use while testing continues. We disagree. We think enough red flags have been raised to warrant more caution. The EPA has ordered that the dog teratogencity tests be repeated. Still, it's liable to be years before the results are in. For now, no one really knows the long-term health effects of carbaryl exposure on human beings. But so many questions have been raised that even the WHO's Acceptable Daily Intake rate of 0.01 milligrams per kilogram of body weight seems like an unacceptable risk. Carbaryl doesn't belong in the garden.
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