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In this study the potential impact of food chain-based biotransformation and physico-chemical weathering of toxaphene on its tumour promoting potential was investigated in vitro and in vivo. Human exposure to toxaphene is mainly through consumption of contaminated fish, therefore fish-borne residues of toxaphene (cod liver extract, CLE) were prepared by exposing cod to technical toxaphene (TT) for 63 days. UV-irradiated toxaphene (uvT) was included to represent a physico-chemical weathered toxaphene mixture. In vitro, TT, uvT and CLE all showed a dose- and time-dependent inhibition of gap junctional intercellular communication (GJIC) with a relative potency of CLE>TT=uvT. Tumour promoting potency was further studied in vivo in a medium term two-stage initiation/promotion bioassay in female Sprague-Dawley rats, using an increase in altered hepatic foci positive for glutathione-S-transferase-P (AHF-GST-P) as read out. No increase in AHF-GST-P occurred following exposure to either TT, uvT, or CLE, except for the positive control group (2,3,7,8-TCDD). Based on this study the no observed adverse effect level (NOAEL) for tumour promoting potency is at least 12.5mg/kg/week, or higher for CLE. Considering current human exposure levels in Europe it is doubtful that consumption of fish at current levels of toxaphene contamination give rise to human health risk.

The well-known and almost universally utilizable clean-up technique of gel permeation chromatography (GPC) and subsequent conventional silica-gel column chromatography was automated by an on-line solvent evaporation of the GPC fraction, followed by normal-phase HPLC separation. The ternary solvent system n-hexane-toluene-acetone (88:10:2, v/v/v) was used as the mobile phase which resulted in only one HPLC fraction for all relevant analytes. The HPLC column was cleaned automatically after each sample by backflushing with polar solvents. The recoveries and reproducibilities of 35 analytes (mainly organochlorine compounds) were in the range of 77-90% and 3-7%, respectively; the high efficiency of the HPLC separation provide very clean extracts for the GC analysis. This automated clean-up technique is routinely used for the multiresidue analysis of various fat-containing food and biota samples.

Increased levels of Dieldrin (0.01-2.94 mg/kg fat, median mean = 0.38 mg/kg fat) and cis-Heptachlor Epoxide (less than 0.01-1.38 mg/kg fat, mean = 0.20 mg/kg fat) were determined by GC/ECD in liver fat of 199 hares (Lepus europaeus L.) from Schleswig-Holstein, North Germany. This investigation was carried out within the scope of a game investigation program. The dependence of these residues on endogenous and exogenous factors are discussed. Oxychlordane and trans-Nonachlor, residues of Chlordane, were also analysed in liver fat by GC/MS. The application of the cyclodiene insecticides Aldrin/Dieldrin, Heptachlor and Chlordane has been prohibited in West Germany for several years; the residues indicate the high soil persistence of these substances.