Bromoxynil
Encyclopedia
Bromoxynil is a nitrile
herbicide
, trade names include Brominal, Bromotril, Bronate, Buctril, Certrol B, Litarol, M&B 10064, Merit, Pardner, Sabre, and Torch. It is used for post-emergent control of annual
broadleaf weeds. It is especially effective in the control of weeds in cereal
, corn
, sorghum
, onion
s, flax
, mint, turf
, and on non-cropland. It works by inhibiting photosynthesis
. Lethal doses in mammals range between 60 and 600 milligrams ingested per kilogram of body weight, and teratogenic effects have been observed in rats and rabbits above 30 milligrams per kilogram. Chronic exposure for more than one year in humans caused symptoms of weight loss, fever, vomiting, headache, and urinary problems in one documented case. In the United States
it is distributed as a Restricted Use Pesticide in toxicity class
II (moderately toxic) and not available for homeowner use.
In the Great Plains region of Canada it is widely used on cereal grains. Average levels detected in drinking water were 1 nanogram per liter, but in one case as high as 384 nanograms per liter were detected. Levels of bromoxynil were consistently lower than of several other pesticides tested, and it was observed to undergo greater reduction in water treatment than the others.
Bromoxynil decomposes readily in soil, with a half life of approximately two weeks. Persistence increases in soils with elevated clay or organic matter content, suggesting the compound has somewhat limited bioavailability
to microorganisms in these environments. Under aerobic conditions in soils or pure cultures, products of bromoxynil degradation often retain the original bromine groups. The herbicide, and one of its common degradation products (3,5-dibromo-4-hydroxybenzoic acid) have been shown to undergo metabolic reductive dehalogenation by the microorganism, Desulfitobacterium chlororespirans.
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
, trade names include Brominal, Bromotril, Bronate, Buctril, Certrol B, Litarol, M&B 10064, Merit, Pardner, Sabre, and Torch. It is used for post-emergent control of annual
Annual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...
broadleaf weeds. It is especially effective in the control of weeds in cereal
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...
, 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...
, sorghum
Sorghum
Sorghum is a genus of numerous species of grasses, one of which is raised for grain and many of which are used as fodder plants either cultivated or as part of pasture. The plants are cultivated in warmer climates worldwide. Species are native to tropical and subtropical regions of all continents...
, onion
Onion
The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...
s, flax
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...
, mint, turf
Sod
Sod or turf is grass and the part of the soil beneath it held together by the roots, or a piece of thin material.The term sod may be used to mean turf grown and cut specifically for the establishment of lawns...
, and on non-cropland. It works by inhibiting photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
. Lethal doses in mammals range between 60 and 600 milligrams ingested per kilogram of body weight, and teratogenic effects have been observed in rats and rabbits above 30 milligrams per kilogram. Chronic exposure for more than one year in humans caused symptoms of weight loss, fever, vomiting, headache, and urinary problems in one documented case. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
it is distributed as a Restricted Use Pesticide in toxicity class
Toxicity Class
Toxicity Class refers to a classification system for pesticides that has been created by a national or international government-related or -sponsored organization...
II (moderately toxic) and not available for homeowner use.
In the Great Plains region of Canada it is widely used on cereal grains. Average levels detected in drinking water were 1 nanogram per liter, but in one case as high as 384 nanograms per liter were detected. Levels of bromoxynil were consistently lower than of several other pesticides tested, and it was observed to undergo greater reduction in water treatment than the others.
Bromoxynil decomposes readily in soil, with a half life of approximately two weeks. Persistence increases in soils with elevated clay or organic matter content, suggesting the compound has somewhat limited bioavailability
Bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
to microorganisms in these environments. Under aerobic conditions in soils or pure cultures, products of bromoxynil degradation often retain the original bromine groups. The herbicide, and one of its common degradation products (3,5-dibromo-4-hydroxybenzoic acid) have been shown to undergo metabolic reductive dehalogenation by the microorganism, Desulfitobacterium chlororespirans.