Names | |
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Preferred IUPAC name 3-(Propan-2-yl)-2λ6,1,3-benzothiadiazine-2,2,4(1H,3H)-trione | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.042.335 |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C10H12N2O3S | |
Molar mass | 240.28 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Bentazon (Bentazone, Basagran, Herbatox, Leader, Laddock) is a chemical manufactured by BASF Chemicals [1] for use in herbicides. It is categorized under the thiadiazine group of chemicals. [2] Sodium bentazon is available commercially [2] and appears slightly brown in colour. [1]
Bentazon is a selective herbicide as it only damages plants unable to metabolize the chemical. [1] It is considered safe for use on alfalfa, beans (with the exception of garbanzo beans [1] ), maize, peanuts, peas (with the exception of blackeyed peas [1] ), pepper, peppermint, rice, sorghum, soybeans and spearmint; as well as lawns and turf. [3] Bentazon is usually applied aerially or through contact spraying on food crops to control the spread of weeds occurring amongst food crops. Herbicides containing bentazon should be kept away from high heat as it will release toxic sulfur and nitrogen fumes. [1] [2]
Bentazon is currently registered for use in the United States in accordance with requirements set forth by the United States Environmental Protection Agency. [4] However, as of September 2010, the herbicides Basagran M60, Basagran DF, Basagran AG, Prompt 5L and Laddock 5L are currently under review for pending requests for voluntary registration cancellation. [5]
In general, bentazon is quickly metabolized and degraded by both plants and animals. However, soil leaching and runoff is a major concern in terms of water contamination. In 1995 the Environmental Protection Agency (EPA) stated that levels of bentazon in both ground water and surface water "exceed levels of concern". [3] Despite the establishment of a 20 parts per billion Health Advisory Level there is no requirement to measure for bentazon in water supplies as the Safe Drinking Water Act does not regulate bentazon. [3] The United States EPA found bentazon in 64 out of 200 wells in California - the highest number of detections in their 1995 study. [3] [6] This prompted the State of California to review existing toxicology studies and establish a "Public Health Goal" that limits bentazon in drinking water to 200 parts per billion.
The EPA requires ground water and environmental hazard advisory labels on all commercially available herbicides containing bentazon. Both statements warn against application and/or disposal of bentazon directly into water, or in areas where soil leaching is common. [3]
A number of limits have been placed on bentazon to reduce the possibility of toxic effects on humans. Tolerance levels vary depending on the use of the food/animal product. The following tolerance levels for bentazon have been established in the United States: [2]
It is recommended that food and feed supplies be stored away from herbicides containing bentazon. [1] Aerial spraying should be conducted in a manner that prevents spray drift towards water sources and food crops susceptible to bentazon. [1]
A 1994 study concluded that bentazon is non-toxic to honeybees, and is not harmful to beetles. [7] Studies have found that bentazon is toxic to rainbow trout and bluegill sunfish at 190 ppm and 616 ppm, respectively. [1] [2] Bentazon is considered toxic to birds as it affects their reproductive capacities. [3]
Among mammals, bentazon is found to be moderately toxic when ingested or absorbed through the skin. Lethal doses (LD50, the dose required to kill half the population being studied) for bentazon have been established for:
Dogs in a study being fed 13.1 mg of bentazon a day developed diarrhoea, anemia and dehydration. [8] In another study using dogs, prostate inflammation was also observed along with previously noted health effects [1] [6] In experiments conducted on hamsters, mice and rats, bentazon was not found to cause gene mutations to damage to DNA and chromosomes. [2]
Bentazon has been classified by the EPA as a "Group E" chemical, because it is believed to be non-carcinogenic to humans (as based on testing conducted on animals). [2] [9] However, there are no studies or experiments that can determine toxic and/or carcinogenic effects of bentazon on humans. Workers applying the herbicide would be most exposed to bentazon, and so have been advised to wear protective clothing (goggles, gloves and aprons) at all times when handling the chemical. [1] Bentazon causes allergy-like symptoms as it irritates the eyes, skin and respiratory tract. [1] [10] Ingesting bentazon causes nausea, diarrhoea, trembling, vomiting and difficulty breathing. [1] [10] Workers handling bentazon must wash their hands before eating, drinking, smoking, and using the bathroom to minimize contact with skin. [3] The effects of bentazon ingestion has been observed in humans who chose the herbicide to commit suicide. [10] Ingestion of bentazon was observed to cause fevers, renal failure (kidney failure), accelerated heart rate (tachycardia), shortness of breath (dyspnea) and hyperthermia. Ingestion of 88 grams of bentazon caused death in an adult. [10]
Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.
A reference dose is the United States Environmental Protection Agency's maximum acceptable oral dose of a toxic substance, "below which no adverse noncancer health effects should result from a lifetime of exposure". Reference doses have been most commonly determined for pesticides. The EPA defines an oral reference dose as:
[A]n estimate, with uncertainty spanning perhaps an order of magnitude, of a daily oral exposure to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime.
Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. Specifically, it causes a blockage of the nicotinergic neuronal pathway. By blocking nicotinic acetylcholine receptors, imidacloprid prevents acetylcholine from transmitting impulses between nerves, resulting in the insect's paralysis and eventual death. It is effective on contact and via stomach action. Because imidacloprid binds much more strongly to insect neuron receptors than to mammal neuron receptors, this insecticide is more toxic to insects than to mammals.
Chlorpyrifos (CPS), also known as Chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, and buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems of insects by inhibiting the acetylcholinesterase enzyme. Chlorpyrifos was patented in 1966 by Dow Chemical Company.
Alachlor is an herbicide from the chloroacetanilide family. It is an odorless, white solid. The greatest use of alachlor is for control of annual grasses and broadleaf weeds in crops. Use of alachlor is illegal in the European Union and no products containing alachlor are currently registered in the United States.
Atrazine is a chlorinated herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), soybean and sugarcane and on turf, such as golf courses and residential lawns. Atrazine's primary manufacturer is Syngenta and it is one of the most widely used herbicides in the United States, Canadian, and Australian agriculture. Its use was banned in the European Union in 2004, when the EU found groundwater levels exceeding the limits set by regulators, and Syngenta could not show that this could be prevented nor that these levels were safe.
Chloropicrin, also known as PS (from Port Sunlight) and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I. Its chemical structural formula is Cl3CNO2.
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 acetylcholine in the synapse. Aldicarb is considered "extremely hazardous" by the EPA and World Health Organization and has been banned in more than 100 countries. In case of severe poisoning, the victim dies of respiratory failure.
Glufosinate is a naturally occurring broad-spectrum herbicide produced by several species of Streptomyces soil bacteria. Glufosinate is a non-selective, contact herbicide, with some systemic action. Plants may also metabolize bialaphos and phosalacine, other naturally occurring herbicides, directly into glufosinate. The compound irreversibly inhibits glutamine synthetase, an enzyme necessary for the production of glutamine and for ammonia detoxification, giving it antibacterial, antifungal and herbicidal properties. Application of glufosinate to plants leads to reduced glutamine and elevated ammonia levels in tissues, halting photosynthesis and resulting in plant death.
Diphenylamine is an organic compound with the formula (C6H5)2NH. The compound is a derivative of aniline, consisting of an amine bound to two phenyl groups. The compound is a colorless solid, but commercial samples are often yellow due to oxidized impurities. Diphenylamine dissolves well in many common organic solvents, and is moderately soluble in water. It is used mainly for its antioxidant properties. Diphenylamine is widely used as an industrial antioxidant, dye mordant and reagent and is also employed in agriculture as a fungicide and antihelmintic.
Methoxychlor is a synthetic organochloride insecticide, now obsolete. Tradenames for methoxychlor include Chemform, Maralate, Methoxo, Methoxcide, Metox, and Moxie.
Dicamba is a selective systemic herbicide first registered in 1967. Brand names for formulations of this herbicide include Dianat, Banvel, Diablo, Oracle and Vanquish. This chemical compound is a chlorinated derivative of o-anisic acid.
Sulfentrazone is the ISO common name for an organic compound used as a broad-spectrum herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase. It was first marketed in the US in 1997 by FMC Corporation with the brand name Authority.
Pesticides in the United States are used predominantly by the agricultural sector, but approximately a quarter of them are used in houses, yards, parks, golf courses, and swimming pools.
Dinoseb is a common industry name for 6-sec-butyl-2,4-dinitrophenol, a herbicide in the dinitrophenol family. It is a crystalline orange solid which does not readily dissolve in water. Dinoseb is banned as an herbicide in the European Union (EU) and the United States because of its toxicity.
Etofenprox is a pyrethroid derivative which is used as an insecticide. Mitsui Chemicals Agro Inc. is the main manufacturer of the chemical. It is also used as an ingredient in flea medication for cats and dogs.
Chlorpropham or CIPC is a plant growth regulator and herbicide used as a sprout suppressant for grass weeds, alfalfa, lima and snap beans, blueberries, cane fruit, carrots, cranberries, ladino clover, garlic, seed grass, onions, spinach, sugar beets, tomatoes, safflower, soybeans, gladioli and woody nursery stock. It is also used to inhibit potato sprouting and for sucker control in tobacco. Chlorpropham is available in emulsifiable concentrate and liquid formulations.
Imazaquin is an imidazolinone herbicide, so named because it contains an imidazolinone core. This organic compound is used to control a broad spectrum of weed species. It is a colorless or white solid, although commercial samples can appear brown or tan.
Fluxapyroxad is a broad-spectrum pyrazole-carboxamide fungicide used on a large variety of commercial crops. It stunts fungus growth by inhibiting the succinate dehydrogenase (SQR) enzyme. Application of fluxapyroxad helps prevent many wilts and other fungal infections from taking hold. As with other systemic pesticides that have a long chemical half-life, there are concerns about keeping fluxapyroxad out of the groundwater, especially when combined with pyraclostrobin. There is also concern that some fungi may develop resistance to fluxapyroxad.
Cyanazine is a herbicide that belongs to the group of triazines. Cyanazine inhibits photosynthesis and is therefore used as a herbicide.