Dioxins and dioxin-like compoundsDioxins and dioxin-like compounds (DLCs) are a group of chemical compounds that are persistent organic pollutants (POPs) in the environment. They are mostly by-products of burning or various industrial processes or, in the case of dioxin-like PCBs and PBBs, unwanted minor components of intentionally produced mixtures. Some of them are highly toxic, but the toxicity among them varies 30,000-fold. They are grouped together because their mechanism of action is the same.
2,4-Dichlorophenoxyacetic acid2,4-Dichlorophenoxyacetic acid is an organic compound with the chemical formula C8H6Cl2O3 which is usually referred to by its ISO common name 2,4-D. It is a systemic herbicide which kills most broadleaf weeds by causing uncontrolled growth in them but most grasses such as cereals, lawn turf, and grassland are relatively unaffected. 2,4-D is one of the oldest and most widely available herbicides and defoliants in the world, having been commercially available since 1945, and is now produced by many chemical companies since the patent on it has long since expired.
Phenoxy herbicidePhenoxy herbicides (or "phenoxies") are two families of chemicals that have been developed as commercially important herbicides, widely used in agriculture. They share the part structure of phenoxyacetic acid. The first group to be discovered act by mimicking the auxin growth hormone indoleacetic acid (IAA). When sprayed on broad-leaf plants they induce rapid, uncontrolled growth ("growing to death"). Thus when applied to monocotyledonous crops such as wheat or maize (corn), they selectively kill broad-leaf weeds, leaving the crops relatively unaffected.
HerbicideHerbicides (ˈɜːrbɪsaɪdz, ˈhɜːr-), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called total weed killers in commercial products) can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact.
Agent OrangeAgent Orange is a chemical herbicide and defoliant, one of the tactical use Rainbow Herbicides. It was used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. It is a mixture of equal parts of two herbicides, 2,4,5-T and 2,4-D. In addition to its damaging environmental effects, traces of dioxin (mainly TCDD, the most toxic of its type) found in the mixture have caused major health problems for many individuals who were exposed, and their offspring.
Herbicidal warfareHerbicidal warfare is the use of substances primarily designed to destroy the plant-based ecosystem of an area. Although herbicidal warfare use chemical substances, its main purpose is to disrupt agricultural food production and/or to destroy plants which provide cover or concealment to the enemy, not to asphyxiate or poison humans and/or destroy human-made structures. Herbicidal warfare has been forbidden by the Environmental Modification Convention since 1978, which bans "any technique for changing the composition or structure of the Earth's biota".
United StatesThe United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America and consisting of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations.
