The Enantioselective Toxicities of Other Chlorinated Pesticides

Besides PCBs and HCH chlorinated pesticides, some other chiral chlorinated pesticides have been reported to possess different enantioselective toxicities. The most important chiral chlorinated pesticides present in 

Commercial DDT and DDD contain o,p-DDT [ 1,1,1-trichloro-2-(c -chlorophenyl)-2-(p-chlorophenyl)] ethane and o,p-DDD [l,l-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)] ethane isomers ( 10-20%), which are chiral [28]. Investigations have demonstrated the oestrogenic activity of o,p-DDT in fish and mammals [29-34]. It is also known that the —)-o,p-DDT enantiomer is a more active oestrogen mimic than the (+)-enantiomer in rats [35, 36]. Subsequently, Hoekstra etal. [37] reported a yeast-based assay to assess the enantiomer-specific transcriptional activity of DDT with 

T able 4.4 The enaatioselective toxicities of the enaatiomers of heptachlor and 2-chlorheptachlor on German cockroach Blattella germanica) [27] 

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