Hexachlorocyclohexanes, effects

Lastly, we will describe how these methods have been used to characterize the effects of hexachlorocyclohexanes on neutrophil functions. Although we are limiting this to a discussion of neutrophils, these approaches are completely generalizable to other cell types and have already been applied to some. We hope this summary will be useful to workers who wish to extend these techniques to the cell systems of interest to them. 

Rijnaarts HHM, A Bachmann, JC Jumelet, AJB Zehnder (1990) Effect of desorption and intraparticle mass transfer on the aerobic biomineralization of alpha-hexachlorocyclohexane in a contaminated calcareous soil. Environ Sci Technol 24 1349-1354. 

Schechter et al. (7) in their studies on DDT in milk found that interfering extractives are largely removed by treatment with strong sulfuric acid. Furman and Hoskins (2) found the same treatment effective when hexachlorocyclohexane was the contaminating substance, and it has been applied in later work to numerous extracts of plants and animals. The procedure now used when either DDT or hexachlorocyclohexane is suspected is as follows ... 

Accessibility of the deposit to the insects by contact is the chief feature of the small vial method, but fumigant action cannot be eliminated entirely. In the case of DDT this has been found to be unimportant, for flies kept in the vials out of contact with the surface are not affected. But with 7-hexachlorocyclohexane or parathion there is a noticeable toxic effect. If the vials are stood upright, laid on the side, or hung upside down, there is a decrease in the mortality produced in the order given. The position on the side has been adopted because it avoids extremes and because practical use of an insecticide often involves limited but not accentuated ventilation. 

Field test work with technically pure gamma isomer of hexachlorocyclohexane has been extensive and involved and is being continued. It was necessary to know such factors as insecticidal value in field applications as compared to other insecticides, as well as residual life, residue from the poison standpoint, and residual taste or odor factors. These factors have been worked out on numerous crops and some of the results are dealt wTith in this paper. Because the pure gamma isomer was found to be effective on insects in the soil as well as on insect infestations on plants, its residual life in soil of all types and effects on tuber and root crops were also of major importance. 

In another AT study, Terrado et al. [15] characterised pollution patterns in different parts of the Ebro catchment. In the upper part of the Ebro, pollution was found to be mainly in the form of heavy metals (Zn, Cu, Cr, Pb, Cd and Hg), polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs) and trichlorobenzenes (TCBs). Etrophic conditions were also found. Pollution was found to source mainly from industry and urbanisation. The central Ebro was characterised by nutrient pollution such as the accumulation of Ca, Na, Mg and K, which highlighted the importance of salinisation effects from intensive irrigation and soils with high salt content. In the lower Ebro, organic [DDTs, hexachlorobenzene (HCB) and hexachlorobutadiene (HCBu)] and heavy metal (Hg, Cd, Zn and As) contamination was found to derive mainly from industrial and agricultural activities. 

Tridevi NP, Rawal UM, Patel BP. (2007) Hepatoprotective effect of andrographolide against hexachlorocyclohexane-induced oxidative injury. Integr... 

Chlorination of benzene gives an addition product that is a mixture of stereoisomers known collectively as hexachlorocyclohexane (HCH). At one time, this was incorrectly termed benzene hexachloride. The mixtnre has insecticidal activity, though activity was found to reside in only one isomer, the so-called gamma isomer, y-HCH. y-HCH, sometimes under its generic name lindane, has been a mainstay insecticide for many years, and is about the only example of the chlorinated hydrocarbons that has not been banned and is still available for general use. Although chlorinated hydrocarbons have proved very effective insecticides, they are not readily degraded in the environment, they accumulate and persist in animal tissues, and have proved toxic to many bird and animal species. 

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 stereochemical conformation of hexachlorocyclohexane (i.e., whether the Cl atoms are axial or equatorial) has no effect on the estimated rate constant for the OH radical reaction. For the purposes of the calculation, all six carbon atoms are therefore equivalent, with each carbon atom being bonded to two carbon atoms (each with substituent H and Cl atoms) and to one H atom and one Cl atom [i.e., (-CHCl-)6]. The rate constant therefore is given by ... 

The gamma isomer of hexachlorocyclohexane was commonly called gamma benzene hexachloride, which was a misnomer, since no benzene ring is present in this compound. Lindane is an effective pediculicide and scabicide. 

Hexachlorocyclohexane, once confusingly called benzene hexachloride (BHC), consists of several stereoisomers with different orientations of H and Cl atoms. The gamma isomer is shown in Figure 16.5. It is an effective insecticide, constituting at least 99% of the commercial insecticide lindane. 

Figure 4.14 Relationship ofa-HCH enantiomer ratios (ERs) in fat of adult female northern fur seals from the Japanese Pacific coast with time (A) and feeding habitat based on average stomach content (B). (Reproduced with permission from Environmental Science and Technology, Enantioselective Accumulation of a-Hexachlorocyclohexane in Northern Fur Seals and Double-Crested Cormorants Effects of Biological and Ecological Factors in the Higher Tropic Levels, by Hisato Iwata, Shinsuke Tanabe etal., 32(15), 2244-2249. Copyright (1998) American Chemical Society)...

Iwata, H. Tanabe, S. lida, T. Baba, N. Ludwig, J.P. Tatsukawa, R., Enantioselective accumulation of a-hexachlorocyclohexane in northern fur seals and double-crested cormorants Effects of biological and ecological factors in the higher trophic levels Environ. Set Technol. 1998, 32, 2244-2249. 

SAFETY PROFILE Moderately toxic by skin contact, inhalation, intravenous, and intraperitoneal routes. Mildly toxic by ingestion. Experimental teratogenic and reproductive effects. A skin and eye irritant. Less toxic than dimethylformamide. Mutation data reported. Combustible when exposed to heat and flame. A moderate explosion hazard. Violent reaction with halogenated compounds (e.g., carbon tetrachloride, hexachlorocyclohexane) when heated above 90°C. Iron powder catalyzes the reaction so that it initiates at 71 °C. 

Isomers of hexachlorocyclohexane (HCH) are found in air, soil, water, food and even breast milk. Lindane is used in large quantities in agriculture and forestry as a wood preservative as well as in veterinary medicine. Provided that the required safety measures are adhered to, no liver damage occurs during the production of lindane. On the other hand, liver cell necrosis was observed in animal experiments after HCH isomers were added to the feed a carcinogenic effect was seen after long-term administration. An increased toxic potential is to be expected when there is simultaneous exposure to DDT, PCB, contraceptives, etc. 

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