Chemistry[ edit ] The technical or chemical name of carbofuran is 2,3-dihydro-2,2-dimethylbenzofuranyl methylcarbamate, and its CAS Number is With this change, carbofuran usage in the United States would be allowed only on corn, potatoes, pumpkins, sunflowers, pine seedlings and spinach grown for seed. Carbofuran is known to be particularly toxic to birds. In its granular form, a single grain will kill a bird. Birds often eat numerous grains of the pesticide, mistaking them for seeds, and then die shortly thereafter.
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Phase-out began on September 1, with a ban on the use of granular carbofuran in certain ecologically sensitive areas. Before , 80 percent of the total usage of carbofuran was in granular formulations. The ban has been established to protect birds and is not related to human health concerns. Bird kills have occurred when birds ingested carbofuran granules, which resemble grain seeds in size and shape, or when predatory or scavenging birds have ingested small birds or mammals which had eaten carbofuran pellets.
There is no ban on liquid formulations of carbofuran 27 , Liquid formulations of carbofuran are classified as Restricted Use Pesticides RUP because of their acute oral and inhalation toxicity to humans. Liquid formulations bear the signal word "Danger. It is used against soil and foliar pests of field, fruit, vegetable and forest crops.
Carbofuran is available in liquid and granular formulations 5 , 25 , 27 , Risks from exposure to carbofuran are especially high for persons with asthma, diabetes, cardiovascular disease, mechanical obstruction of the gastrointestinal or urogenital tracts, or those in vagotonic states Carbofuran may cause contact burns to the skin or eyes Eye protection should be worn when handling carbofuran. A respirator should be worn by applicators of carbofuran 1.
Fires, and the run off from fire control, may produce irritating or poisonous gases Closed spaces storage, etc. Complete recovery from an acute poisoning by carbofuran, with no long term health effects, is possible if exposure ceases and the victim has time to reform their normal level of cholinesterase and to recover from symptoms 7 , For more information on cholinesterase, please refer to the Toxicology Information Brief on Cholinesterase-Inhibition.
Carbamates generally are excreted rapidly and do not accumulate in mammalian tissue. If exposure does not continue, cholinesterase inhibition reverses rapidly. In non-fatal cases, the illness generally lasts less than 24 hours The lethal concentration fifty, or LC50, is that concentration of a chemical in air or water that kills half of the experimental animals exposed to it for a set time period.
This means that a person may drink water containing carbofuran at or below this level daily over the course of their lifetime with no health effects. Consuming carbofuran at high levels well above the LHA level over a long period of time has caused damage to the testes and uterus of test animals.
It has also caused cholinesterase inhibition in both humans and test animals Reproductive Effects Daily feeding of ppm of carbofuran to pregnant rats greatly reduced the ability of the pups to survive. Non-fatal liver changes occurred in mice pups 6. Mutagenic Effects No mutagenic effects have been reported in animals or bacteria using the Ames Assay: J. Health 7 Genetic changes have been shown in algae Microbios. Carcinogenic Effects Sufficient data are available from animal studies to indicate that carbofuran does not pose a risk of cancer to humans However, N- nitrosocarbamates are potent mutagens and carcinogens.
They can be made under the acidic conditions of the stomach of some animals. Humans are possible candidates J. Health 14 Fate in Humans and Animals Carbofuran is poorly absorbed through the skin It is metabolized broken-down in the liver and eventually excreted in the urine. The half-life is from hours. One granule is sufficient to kill a small bird. Bird kills have occurred when birds ingested carbofuran granules, which resemble grain seeds in size and shape, or when predatory or scavenging birds have ingested small birds or mammals which had eaten carbofuran pellets Carbofuran is very toxic to pheasants, chickens, fulvous tree ducks and Japanese quail 4.
Red shouldered hawks have been poisoned after eating prey from carbofuran treated fields J. Wildlife Manage. Levels of carbofuran occurring in Kansas fields have been high enough to cause a reduction in the weight, food intake and ability to move of adult male bobwhites Arch.
Effects on Fish Carbofuran may be teratogenic to frogs Toxicol. It is very toxic to trout, Coho salmon, perch Hdbk. It is therefore expected to have a high potential for groundwater contamination 31 , Curr. Carbofuran was mobile to very mobile in sandy , silt loam, silty clay and silty clay loam soils; moderately mobile in silty clay and silty clay loam soils; and only slightly mobile in muck soils.
Carbofuran has been detected at very low 1 to 5 ppb in water table aquifers beneath sandy soils in New York and Wisconsin In soil, carbofuran is degraded by chemical hydrolysis and microbial processes. Hydrolysis occurs more rapidly in alkaline soils Soil microorganisms are better at breaking down large amounts of carbofuran if the soil is pretreated with a small amount of carbofuran J.
Health Part B, B 1 Carbofuran breaks down in sunlight Menzie. Breakdown of Chemical in Water In water, carbofuran is subject to degradation by chemical hydrolysis under alkaline conditions.
Photodegradation and aquatic microbes may also contribute to degradation. The hydrolysis half-lives of carbofuran in water at 25 degree C are , 8. Carbofuran does not volatilize from water nor does it adsorb to sediment or suspended particles. It does not bioaccumulate in aquatic systems Breakdown of Chemical in Vegetation The half-life of carbofuran on crops, when applied to the roots, is about 4 days and longer than 4 days if applied to the leaves Menzie.
Thermal decomposition may include toxic oxides of nitrogen 28 , Occupational Exposure Limits:.
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Producer: FMC Corporation 2. The empirical formula is C12H15N03, and the molecular weight is Solubility in water is ppm. Toxicological Characteristics Current available acute toxicological studies on carbofuran show the following: - Acute oral toxicity: rat, LD50 3. Assumed to be Toxicity Category I Major routes of exposure: Application by ground and aerial spray equipment increases the potential for exposure of humans, livestock, and wildlife due to spray drift. Human exposure to carbofuran from handling, application, and reentry operations would be minimized by the use of approved respirators and other protective clothing. Like other carbamates, it is metabolized rapidly in animals into less toxic and finally non-toxic metabolites.
Phase-out began on September 1, with a ban on the use of granular carbofuran in certain ecologically sensitive areas. Before , 80 percent of the total usage of carbofuran was in granular formulations. The ban has been established to protect birds and is not related to human health concerns. Bird kills have occurred when birds ingested carbofuran granules, which resemble grain seeds in size and shape, or when predatory or scavenging birds have ingested small birds or mammals which had eaten carbofuran pellets. There is no ban on liquid formulations of carbofuran 27 ,