Nonachlors

Transmission lines Transmission loss Transmitters Trans-nonachlor... 

Mit Trikalium-nonachlor-diwolfram(III) lassen sich Sulfoxide in ausgezeichneten Aus-beuten zu Sulfanen reduzieren2 ... 

Metabolism of chlordanes and nonachlors to oxychlordane is orders of magnitude greater in fisheating and carnivorous birds than in marine mammals (Kawano et al. 1988). The reasons for this are unclear and merit further research. 

Although technical chlordane is a mixture of compounds, two metabolites — heptachlor epoxide and oxychlordane — can kill birds when administered through the diet (Blus et al. 1983). These two metabolites originate from biological and physical breakdown of chlordanes in the environment, or from metabolism after ingestion. Heptachlor can result from breakdown of cis- and trans-chlordane, eventually oxidizing to heptachlor epoxide oxychlordane can result from the breakdown of heptachlor, m-chlordane, tra .s-chlordane, or fram-nonachlor (Blus et al. 1983). Heptachlor epoxide has been identified in soil, crops, and aquatic biota, but its presence is usually associated with the use of heptachlor, not technical chlordane — which also contains some heptachlor (NRCC 1975). Various components in technical chlordane may inhibit the formation of heptachlor epoxide or accelerate the decomposition of the epoxide, but the actual mechanisms are unclear (NRCC 1975). 

Chlordanes and their metabolites are ubiquitous in the environment at low concentrations, but at a high occurrence in samples analyzed. Atmospheric transport is considered to be the major route of global dissemination. Some chlordane isomers persist in soils for 3 to 15 years, although there seems to be little accumulation of chlordanes by crop plants grown in these soils. Lengthy persistence of various chlordane isomers, especially m-chlordane and trans-nonachlor, has been reported in certain organisms, but this has varied greatly between species and tissues. 

Chlordane residue data for amphibians and reptiles are extremely limited. Maximum concentrations of chlordane isomers did not exceed 70 pg/kg FW of oxychlordane in eggs of the American crocodile, Crocodylus acutus, or 250 pg/kg FW in carcass of the common garter snake, Thamnophis sirtalis (Table 13.2). However, California newts, Tarichia torosa, taken near a lake treated with 10 pg/L technical chlordane had greatly elevated chlordane residues in liver and comparatively low concentrations in carcass, stomach, and stomach contents. After 14 days, livers contained about 34 mg/kg total chlordanes lipid weight — about 19% chlordanes, 9% nonachlors, and 6% chlor-denes (Albright et al. 1980). After 2.8 years, 98% of the total chlordanes was lost. 7ra .v-nonachlor was the most persistent component in newt liver, accounting for up to 55% of the total chlordanes in specimens collected 2.8 years after application (Table 13.2) (Albright et al. 1980). 

Chlordane levels in human blood were comparatively elevated among individuals living in residences treated with chlordane during the past 5 years, and in termite control operators. Oxychlordane levels were usually significantly higher than /ra/u-nonachlor, except among those who consumed large quantities of fish (Wariishi et al. 1986 Wariishi and Nishiyama 1989). 

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