Carbofuran
Encyclopedia
Carbofuran is one of the most toxic carbamate
pesticide
s. It is marketed under the trade names Furadan, by FMC Corporation and Curater, among several others. It is used to control insects in a wide variety of field crops, including potatoes, corn
and soybean
s. It is a systemic insecticide, which means that the plant absorbs it through the roots, and from here the plant distributes it throughout its organs where insecticidal concentrations are attained. Carbofuran also has contact activity against pests.
Carbofuran usage has increased in recent years because it is one of the few insecticides effective on soybean aphid
s, which have expanded their range since 2002 to include most soybean-growing regions of the U.S.
The main global producer is the FMC Corporation.
with 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran.
and the European Union
.
In 2008, the United States Environmental Protection Agency
(EPA) announced that it intends to ban carbofuran. In December of that year, FMC Corp.
, the sole US manufacturer of carbofuran, announced that it had voluntarily requested that the United States
Environmental Protection Agency cancel all but 6 of the previously allowed uses of that chemical as a pesticide. With this change, carbofuran usage in the US would be allowed only on maize, potatoes, pumpkins, sunflowers, pine seedlings and spinach grown for seed. However, in May 2009 EPA cancelled all food tolerances, an action which amounts to a de facto ban on its use on all crops grown for human consumption.
Kenya is considering banning carbofuran, but it is legal to buy over-the-counter
in Kenya.
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. Before the granular form was banned by U.S. Environmental Protection Agency in 1991, it was blamed for millions of bird deaths per year. The liquid version of the pesticide is less hazardous to birds since they are not as likely to ingest it directly, but it is still very hazardous. The EPA announced on July 25, 2008 that it intends to ban all forms in the US. The ban requires that no residue be present on domestic or imported foods.
Carbofuran has been illegally used to intentionally poison wildlife in the US, Canada and Great Britain; poisoned wildlife have included coyotes, kites, golden eagles and buzzards. Secondary fatal poisoning of domestic and wild animals has been documented, specifically, raptors
(bald eagles and golden eagles), domestic dogs, raccoon
s, vulture
s and other scavengers. In Kenya
, farmers are using carbofuran to kill lions and other predators.
In a number of publicized incidents worldwide, carbofuran has also been used to poison domestic pets.
and parathion
are more toxic). A quarter teaspoon (1 mL) can be fatal. Most carbofuran is applied by commercial applicators using closed systems with engineered controls so there is no exposure to it in preparation. Since its toxic effects are due to its activity as a cholinesterase
inhibitor it is considered a neurotoxic
pesticide.
Carbofuran is also a powerful endocrine disruptor that can cause transient alterations in the concentration of many hormones in animals and humans even at extremely low doses. These alterations may consequently lead to serious reproductive problems following repeated exposure. In one study, the exposure of rats to sublethal amounts of carbofuran decreased testosterone
by 88%, while the levels of progesterone
, cortisol
, and estradiol
were significantly increased (1279%, 202%, and 150%, respectively).
Carbofuran can also be toxic to testes in sublethal amounts. A decrease in sperm motility, sperm count along with increase in percent abnormal sperm was observed at 0.4 mg/kg dose level.
Carbamate
Carbamates are organic compounds derived from carbamic acid . A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally and often are interconverted chemically. Carbamate esters are also called urethanes.-Synthesis:Carbamic acids are derived...
pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s. It is marketed under the trade names Furadan, by FMC Corporation and Curater, among several others. It is used to control insects in a wide variety of field crops, including potatoes, corn
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
and soybean
Soybean
The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
s. It is a systemic insecticide, which means that the plant absorbs it through the roots, and from here the plant distributes it throughout its organs where insecticidal concentrations are attained. Carbofuran also has contact activity against pests.
Carbofuran usage has increased in recent years because it is one of the few insecticides effective on soybean aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
s, which have expanded their range since 2002 to include most soybean-growing regions of the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
The main global producer is the FMC Corporation.
Chemistry
The technical or chemical name of carbofuran is 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate and its CAS number is 1563-66-2. It is manufactured by the reaction of methyl isocyanateMethyl isocyanate
Methyl isocyanate is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane, methyl carbylamine, and MIC. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides . It has also been used in the production of rubbers and adhesives...
with 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran.
Bans
Carbofuran is banned in CanadaCanada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
and the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
.
In 2008, the United States Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
(EPA) announced that it intends to ban carbofuran. In December of that year, FMC Corp.
FMC Corp.
FMC Corporation is a chemical manufacturing company headquartered in Philadelphia, Pennsylvania. FMC employs over 4,800 people world wide, and had gross revenues of US$3.115 billion in 2008.-The Bean Spray Pump Company:...
, the sole US manufacturer of carbofuran, announced that it had voluntarily requested that the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Environmental Protection Agency cancel all but 6 of the previously allowed uses of that chemical as a pesticide. With this change, carbofuran usage in the US would be allowed only on maize, potatoes, pumpkins, sunflowers, pine seedlings and spinach grown for seed. However, in May 2009 EPA cancelled all food tolerances, an action which amounts to a de facto ban on its use on all crops grown for human consumption.
Kenya is considering banning carbofuran, but it is legal to buy over-the-counter
Over-the-counter drug
Over-the-counter drugs are medicines that may be sold directly to a consumer without a prescription from a healthcare professional, as compared to prescription drugs, which may be sold only to consumers possessing a valid prescription...
in Kenya.
Toxicity to vertebrates
Carbofuran is highly toxic to vertebrates with an oral of 8–14 mg/kg in rats and 19 mg/kg in dogs.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. Before the granular form was banned by U.S. Environmental Protection Agency in 1991, it was blamed for millions of bird deaths per year. The liquid version of the pesticide is less hazardous to birds since they are not as likely to ingest it directly, but it is still very hazardous. The EPA announced on July 25, 2008 that it intends to ban all forms in the US. The ban requires that no residue be present on domestic or imported foods.
Carbofuran has been illegally used to intentionally poison wildlife in the US, Canada and Great Britain; poisoned wildlife have included coyotes, kites, golden eagles and buzzards. Secondary fatal poisoning of domestic and wild animals has been documented, specifically, raptors
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
(bald eagles and golden eagles), domestic dogs, raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
s, vulture
Vulture
Vulture is the name given to two groups of convergently evolved scavenging birds, the New World Vultures including the well-known Californian and Andean Condors, and the Old World Vultures including the birds which are seen scavenging on carcasses of dead animals on African plains...
s and other scavengers. In Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, farmers are using carbofuran to kill lions and other predators.
In a number of publicized incidents worldwide, carbofuran has also been used to poison domestic pets.
Toxicity to humans
Carbofuran has one of the highest acute toxicities to humans of any insecticide widely used on field crops (only aldicarbAldicarb
Aldicarb is a carbamate insecticide which is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide. Aldicarb is a cholinesterase inhibitor which prevents the breakdown of...
and parathion
Parathion
Parathion, also called parathion-ethyl or diethyl parathion, is an organophosphate compound. It is a potent insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, including humans. Its use is banned or restricted in many...
are more toxic). A quarter teaspoon (1 mL) can be fatal. Most carbofuran is applied by commercial applicators using closed systems with engineered controls so there is no exposure to it in preparation. Since its toxic effects are due to its activity as a cholinesterase
Cholinesterase
In biochemistry, cholinesterase is a family of enzymes that catalyze the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation.-Types:...
inhibitor it is considered a neurotoxic
Neurotoxin
A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
pesticide.
Carbofuran is also a powerful endocrine disruptor that can cause transient alterations in the concentration of many hormones in animals and humans even at extremely low doses. These alterations may consequently lead to serious reproductive problems following repeated exposure. In one study, the exposure of rats to sublethal amounts of carbofuran decreased testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
by 88%, while the levels of progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
, cortisol
Cortisol
Cortisol is a steroid hormone, more specifically a glucocorticoid, produced by the adrenal gland. It is released in response to stress and a low level of blood glucocorticoids. Its primary functions are to increase blood sugar through gluconeogenesis; suppress the immune system; and aid in fat,...
, and estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
were significantly increased (1279%, 202%, and 150%, respectively).
Carbofuran can also be toxic to testes in sublethal amounts. A decrease in sperm motility, sperm count along with increase in percent abnormal sperm was observed at 0.4 mg/kg dose level.