Beta-HCH

Produced by fungi which can contaminate crops. Some, such as zearalenone, are oestrogenic DDT, lindane and beta-HCH are common, persistent environmental pollutants Widespread, persistent environmental pollutants... 

The first commercially available HCH insecticide sometimes misleadingly called benzene hexachloride (BHC) was a mixture of isomers, principally alpha HCH (65-70%), beta HCH (7-10%), and gamma HCH (14-15%). Most of the insecticidal activity was due to the gamma isomer (Figure 5.1), a purified preparation of which (>99% pure) was marketed as lindane. In Western countries, technical HCH was quickly replaced by lindane, but in some other countries (e.g., China) the technical product, which is cheaper and easier to produce, has continued to be used. HCH has been used as a seed dressing, a crop spray, and a dip to control ectoparasites of farm animals. It has also been used to treat timber against wood-boring insects. 

Duinker JC, Hillebrand MTJ. 1979. Behaviour of PCB, pentachlorobenzene, hexacMorobenzene, alpha-HCH, gamma-HCH, beta-HCH, dieldrin, endrin and p,p -DDD in the Rhine-Meuse estuary and the adjacent coastal area. Neth J Sea Res 13 256-281. 

Affiland, Ans-Liege, Belgium hCG-beta,hCH, GRF, IGF-1, EPO, clenbuterol, salbutamol... 

Of the other HCH isomers, the alpha and beta forms are less toxic than the gamma form. However, the beta form is more persistent than the gamma form, and unacceptably high residues have sometimes been reported in foods originating from countries where technical HCH is still used (Environmental Health Criteria 123). 

Mossner, S. Spraker, T.R. Becker, P.R. BaUschmiter, K., Ratios of enantiomers of alpha-HCH and determination of alpha-, beta-, and gamma-HCH in brain and other tissues of neonatal Northern fur seals (Callorhinus ursinus) Chemosphere 1992, 24, 1171-1180. 

A portion of pesticides administered is accumulated in an unaltered form, and a further fraction may undergo different biotransformations. For example, DDT can be partially metabolized to DDA, DDD or DDE depending on the organism. HCH is accumulated in the form of alpha, beta, gamma and delta isomers. The accumulation of compounds in the organism is also altered on changing their chemical structure. 

SYNONYMS 1 -alpha,2-alpha,3-beta,4-alpha,5-beta,6-beta-hexachlorocylcohexane, ben-zene-trans-hexachloride, alpha-1,2,3,4,5,6-hexachlorocyclohexane, cyclohexane, 1,2,3,4,5,6-hexachloror-,alpha-isomer, alpha-lindane, alpha-hch, alpha-hexachlorane hexachlorocyclohex-... 

SYNONYMS benzenehexachloride, delta- HCCH, delta-HCH, TBH, 1-alpha,2-alpha,3-alpha,4-beta,5-alpha,6-beta-hexachlorocyclohexane, delta-bhc, delta-lindane... 

Whole-body autoradiographic studies on the distribution of alpha-, beta- and gamma-HCH indicated their relatively rapid urinary excretion 51.0, 8.5 and 1.5% of administered labelled gamma-HCH were excreted at the first, second, and third day after intraperitoneal injection to mice (Nakajima et al. 1970). Results of autoradiographic studies were presented by Kurihara (1973), also. 

Stein et al. (1977) (Fig. 3), supposed the HCH hydroxylation to hexachlorocyclohexanols (I) to explain the polychlorophenol formation from HCH. This alpha-chlorohydrin (I) that results would be expected to eliminate spontaneously HCl to form a ketone, 2,3,4,5,6-pentachloro-cyclohexanone-(l) (II). An elimination of two pairs of H C1 in alpha beta-position to the keto-function yielding a symmetrical trichlorocyclo-hexadienone (III) now could be imaginable. Intermediate (III) could be stabilized by tautomerization to 2,4,6-TCP. The authors stated a high extent of conjugation (in vivo 90% ) of this TCP. 

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