Диэлдрин: қасиеттері, зияны және қолданылуы

chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 460784423
| Name = Dieldrin
| ImageFile1 = Dieldrin 3D balls. png
| ImageFile2 = Dieldrin. svg
| ImageName = Dieldrin
| IUPACName = (1aR,2R,2aS,3S,6R,6aR,7S,7aS) 3,4,5,6,9,9 hexachloro 1a,2,2a,3,6,6a,7,7a octahydro 2,7:3,6 dimethanonaphtho[2,3 b]oxirene
| OtherNames = Dieldrin, HEOD
|Section1=
|Section2=Chembox Properties
| C=12 | H=8 | Cl=6 | O=1
| MolarMass = 380.91 g/mol
| Density = 1.75 g/cm3
| MeltingPtC = 176 to 177
| MeltingPt notes =
| BoilingPtC = 385
| Appearance = colorless to light tan crystals
| Solubility = 0.02%
| IDLH = Ca [50 mg/m3]
| FlashPt = noncombustible
| FlashPt ref = For this reason, it is now banned in most of the world. It has been linked to health problems such as Parkinson's, breast cancer, and immune, reproductive, and nervous system damage. It is also an endocrine disruptor, acting as an estrogen and antiandrogen, and can adversely affect testicular descent in the fetus if a pregnant woman is exposed to it.

The chemicals dieldrin and aldrin were widely applied in agricultural areas throughout the world. They are synthetic organochlorine cyclodiene pesticides used to control subterranean insect pests such as nargles root maggots, mole cricket grubs and weevils, in agriculture. Both are toxic and bioaccumulative. Aldrin does break down to dieldrin in living systems, but dieldrin is known to resist bacterial and chemical breakdown processes in the environment. Both dieldrin and aldrin have been banned (see Legislation and history below). Aldrin was used to control soil pests (namely termites) on corn and potato crops. Dieldrin was an insecticide used on fruit, soil, and seed. It persists in the soil with a half life of five years at temperate latitudes. Both aldrin and dieldrin may be volatilized from sediment and redistributed by air currents, contaminating areas far from their sources. They have been measured in Arctic wildlife, suggesting long range transport from southern agricultural regions.

The metabolism of dieldrin occurs by various routes. Hydration of the epoxy group by epoxide hydrolases leads to formation of the trans diol and to the dicarboxylic acid. The diol is the most important metabolite produced by the rabbit. In the rat, the primary route of metabolism is hydroxylation of the CH2 group by liver microsomal monooxygenases, leading to production of 9 hydroxydieldrin. It is likely that this is an example of enterohepatic recirculation, for bile contains the glucuronide. This is probably cleaved by gut microflora. There is an interesting metabolite in rat urine, first described by Klein. The methylene group of the dieldrin links to one end of the ClC:CCl group to form a cage structure. The other end of the original ClC:CCl is converted to a ketone. The same metabolite is produced from the photoisomer of dieldrin, in which the same cage structure is produced, but the other end of the original chlorinated double bond forms a CHCl group.

Both aldrin and dieldrin have been banned in most developed countries, but aldrin is still used as a termiticide in Malaysia, Thailand, Venezuela and parts of Africa. In Canada, their sale was restricted in the mid 1970s, with the last registered use of the compounds in Canada being withdrawn in 1984. The International Programme on Chemical Safety quotes the World Health Organization as stating dieldrin is prohibited for use in agriculture in, among others, Brazil, Ecuador, Finland, the German Democratic Republic, Singapore, Sweden, Yugoslavia, and the USSR. The European Community legislation prohibits the marketing of phytopharmaceutical products containing dieldrin. In Argentina, Canada, Chile, the Federal Republic of Germany, Hungary, and the US, its use is prohibited, with some exceptions. The use of dieldrin is restricted in India, Mauritius, Togo, and the United Kingdom. Its use in industry is prohibited in Switzerland and its manufacture and use in Japan is under government control. In Finland, the only accepted use for dieldrin is as a termiticide in one glue mixture for exported plywood. India requires registration and licences for all importation, manufacture, sale, or storage. Momentum against organochlorine and similar molecules continued to grow internationally, leading to negotiations that matured as the Stockholm Convention on Persistent Organic Pollutants(POPs). POPs are defined as hazardous and environmentally persistent substances which can be transported between countries by the Earth's oceans and atmosphere. Most POPs (including dieldrin) bioaccumulate in the fatty tissues of humans and other animals. The Stockholm Convention banned twelve POPs, nicknamed "the dirty dozen". These include aldicarb, toxaphene, chlordane and heptachlor, chlordimeform, chlorobenzilate, DBCP, DDT, "drins" (aldrin, dieldrin and endrin), EDB, HCH and lindane, paraquat, parathion and methylparathion, pentachlorophenol, and 2,4,5 T. This took force on 17 May 2004. Australia ratified the Convention only three days later and became a party to it in August that year. Throughout this time, continuous pressure was maintained by relevant committees, for example the Technical Committee on Agricultural Chemicals (TCAC), to reduce approved organochlorine use. By 1981, the use of dieldrin worldwide was limited to sugarcane and bananas, and these uses were deregistered by 1985. In 1987, a nationwide recall system was put into place, and in December of that year, the government prohibited all imports of these chemicals into Australia without express ministerial approval. In 1994, the National Registration Authority for Agricultural and Veterinary Chemicals published a use of organochlorines in termite control, recommending the phase out of organochlorines used in termite control upon development of viable alternatives. The same year, the Agriculture and Resource Management Council of Australia and New Zealand decided to phase out remaining organochlorine uses by 30 June 1995, with the exception of the Northern Territory. In November 1997, the use of all organochlorines other than mirex was phased out in Australia. Remaining stocks of mirex are to be used only for contained baits for termites in plantations of young trees in the Northern Territory until stocks run out, which is expected in the near future. The recognition of negative impacts on health has stimulated the implementation of multiple legislative policies in regards to the use and disposal of organochlorine pesticides. For example, the Environment Protection (Marine) Policy 1994 became operational in May 1995 in South Australia. It dictated the acceptable concentration of toxicants such as dieldrin in marine waters and the manner in which these levels must be tested and tried.