Toxaphene restrictions

Lindane (gamma-hexachlorocyclohexane) is one of the last of the old style organochlorine pesticides still in use. Use of organochlorines such as DDT, aldrin, dieldrin, heptachlor, and toxaphene is restricted or banned in many countries because of their persistence in the environment, bioaccumulation, and toxicity. Lindane was first isolated in 1825 along with other similar compounds, but its deadly effects on insects were not recognized until the 1940s. 

The elevated toxaphene levels in Lake Superior have social and economic impacts as well. The 2003 Guide to Eating Sport Fish published by the Ontario Ministry of Environment and Energy [158] indicates fish consumption advisories for Lake Superior lake trout due to toxaphene levels. As a result of the high toxaphene levels, the Ontario Ministry of Natural Resources has restricted sale with Ontario (but not the export) of large lake trout harvested from Lake Superior as of 1995. An assessment of toxaphene levels in Lake Superior fish fillets by Health Canada concluded that consumption of lake trout, salmon, longnose sucker and whitefish muscle from northwestern areas of the lake should be limited to one or two meals per month (55-135 g/week) based on a provisional tolerable daily intake of 0.2 pg/g body wt/day [159]. 

Toxaphene (CioHio(- 18) is a mixture of polychlorinated camphenes (bicyclic terpenes). Currently in restricted use as an insecticide, it is toxic to fish, birds and wildlife and may be fatal to shrimp, and crab, etc. (ref. 103, p. 26). Its toxicity and routes of entry in mammals are typical of the cyclic chlorinated hydrocarbons as a class ... 

The Stockholm Convention is a global treaty committing the international community to protecting human health and the environment from the potentially harmful effects of POPs (UNEP Chemicals, 2005). The United Nations Environment Programme (UNEP) has identified 12 most toxic POPs (the Dirty Dozen ) for control under the Convention, including 10 intentionally produced POPs pesticides/industrial chemicals (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex, toxaphene and polychlorinated biphenyls (PCBs)) and two unintentionally produced POPs by-products (polychlorinated dibenzo-/ -dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)). In implementing the Convention, Parties to the Convention will take measures to restrict the trade, production and use of the intentional POPs and to reduce and, where possible, to ultimately eliminate the production and release of the unintentional POPs by-products. 

In Hong Kong, the nine intentional POPs pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, HCB, mirex and toxaphene) targeted for global elimination or restricted production and use were not registered, or their registration status had been cancelled for many years due to toxicological or environmental concern. 

Import, export, manufacture, and possession of hazardous substances have been controlled under the Hazardous Substances Act, 1992. However, banning of the import or severely restricted uses of chemicals had been notified in the Ministerial Notifications since 1977. Two insecticides, namely chlordimeform and leptophos were the first two of the banned chemicals in 1977. According to the Act, Ministerial Notifications of the Ministry of Industry were issued to harming of nine specified POPs pesticides usage since 1980 (Table 10.4). Only seven specified POPs pesticides were imported and widely used in Thailand, namely aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, and toxaphene, whereas hexachlorobenzene and mirex have never been imported. Although... 

These restrictions allow a maximum degree of chlorination of only eleven, however, the presence of dodeca chlorobornanes in toxaphene has been reported [3]. Recently, the so-called bridge- and-exo rule was formulated which states that C8 dichloromethyl groups require an exo-chloro on C6, and dichloro-methyl groups on C9 an exo-chloro on C2 [51]. Table 3 summarizes the theoretically possible numbers of isomers and congeners of substance classes present in technical toxaphene and compares them to the variety in other classes of organochlorines. 

The complex composition of toxaphene also creates nomenclature problems. Initially, toxaphene was the trademark of the product manufactured by the Hercules Inc. However, due to the non-restricted use of the trademark, toxaphene has become a general term for this pesticide. Further frequently applied terms were camphechlor , polychlorinated bornanes , camphenes , and ter-penes , as well as chlorobornanes . The expression toxaphene is not the same as the trademark Toxaphene , since residues in the environment may also originate from other technical products (see Table 2). Toxaphene is the reaction product of the chlorination of technical camphene is a suitable definition of the expression used in the scientific language [27]. Owing to the problems with abbreviations as described below, toxaphene will be used in the following chapters as a synonym for the compounds of technical toxaphene. 

Therefore, analysis of microbial-controlled samples on the basis of the most frequently determined toxaphene compounds in fish may result in not detectable toxaphene quantities though B6-923 and B7-1001 are abundant. This clearly demonstrates the restriction of a not matrix optimized congener-specific analysis. 

Chromatographic enantioseparation of chiral xenobiotics and their metabolites is a versatile tool for process studies in marine and terrestrial ecosystems [235]. In 1994, three papers focused on the enantioselective determination of toxaphene components [120,236,237]. Buser and Muller found that technical toxaphene mixtures are not necessarily racemic [237]. This observation was supported after isolation of non-racemic B7-1453 from the product Melipax which had an excess of ca. 25% of the dextrorotary enantiomer [27, 238]. The enantioselective separation of toxaphene components is almost restricted to chiral stationary phases (CSPs) based on randomly derivatized ferf-butyldimethyl-silylated /1-cyclodextrin (commercially available from BGB Analytik, Adliswil, Switzerland). So far, only a few toxaphene components were enantioseparated on other CSPs [239, 240]. Some of these CSPs are not well defined as well, and for this reason a test mixture called CHIROTEST X was suggested for initial column testing [241],... 

By 1971, the concerns about human health and environmental impacts led Monsanto, the producer of PCBs in the United States, to a voluntary ban on sales of PCBs except for closed systems use. Monsanto ceased all production in 1977 and there was no large-scale increase in imports. PCBs were banned from production and further use in the United States in 1978. Equipment that already contained PCBs, e.g., transformers, were allowed to remain in use but restrictions were placed on the disposal of PCBs when the equipment was decommissioned. Delegates from 122 countries completed a draft treaty on persistent organic pollutants (POPs) in December 2000. The POPs that were initially addressed and banned from further use include chlordane, DDT, dieldrin, endrin, heptachlor, mirex, toxaphene, PCBs, hexachlorbenzene, chlorinated dibenzofurans, and chlorinated dibenzodioxins. Fimited selective use of DDT for human disease vector control is allowed in some countries. 

In the industry of insecticides, one of the central issues is to develop products that are not harmful to the environment and to human health. It has been shown that a-pinene, camphor and limonene can be good natural repellents for insects [155]. Besides the use of geraniol in the industry of fragrances, this compoxmd has also proven effective as a mosquito repellent [156, 157]. Terpene halides, 3-carene, and toxaphene, a chlorinated camphene, are important for agriculture because of their use as pesticides [158, 159]. However, especially for toxaphene, several restriction issues have been raised because of its pollutant capacity and carcinogenic potential in humans [159-161]. 

Toxaphene Increasing restrictions Broad-spectmm insecticide for cotton and other nonfood crops restricted to scabies control in cattle and sheep in 1986... 

Most other western countries have either curtailed or limited the use of DDT. In Europe, endrin is limited to the control of rodents, whereas lindane, toxaphene, and endosulfan find broader application (Heckman, 1981). Dieldrin is still used in many western nations as a moth-proofer for the textiles industry. In South Africa, there are no registered uses of DDT, endosulfan, arid heptachlor (Van Dyk etal., 1982). Aldrin, chlordane, dieldrin, and endrin find some application, whereas there are only a few restrictions on the use of lindane. 

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