RP6 Chiral Chemistry: Toxicology of Environmental Contaminants and Phase Transfer
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(LEH-1117-807124) Disposition of Chiral PCBs in the Laboratory Rat.

Lehmler, H.¹, Kania-Korwel, I.^{1, 2}, Avants, J.³, Hornbuckle, K.⁴, Robertson, L.¹, Sulkowski, W.², Garrison, A.³, ¹ Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA² Department of Environmental Chemistry and Technology, University of Silesia, Katowice, Poland³ U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia, USA⁴ Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa, USA

ABSTRACT- In order to investigate the tissue distribution and enantiomeric fractions (EFs) of Polychlorinated Biphenyl (PCB) atropisomers, immature male Sprague-Dawley rats were administered environmentally relevant doses of (a) Aroclor 1254 or (b) an environmental mixture extracted from soil contaminated with Chlorofen, a Polish PCB mixture. Tissue PCB extracts were separated by chiral capillary gas chromatography with electron capture detection using a Chirasil-Dex column. The comparison of the EFs of PCBs 84, 91, 95, 132, 135, 136, 149, 174 and 176 reveals drastic differences between the two treatment groups. The EFs of PCB 95 (adipose tissue, liver and skin), PCB 149 (adipose tissue, liver, skin and blood), PCB 135 (liver) and PCB 174 (kidney) in tissues from Aroclor 1254-treated animals differed significantly from EFs measured in the Aroclor standard, while only EFs of PCB 95 (blood), PCB 135 (adipose tissue and skin) and PCB 174 (adipose tissue) in tissues from soil extract-treated animals were different from the Chlorofen soil extract standard. No statistically significant enantiomeric enrichment was observed for PCB 149 in tissues from soil extract-treated animals. In this study cytochrome P-450 1A activity was 28.7 times higher in the Aroclor group whereas cytochrome P-450 2B activity was 4.7 times higher in soil extract treated animals. The differences in the induction of PCB metabolizing enzymes may be responsible for the differences in the enantiomeric enrichment between both groups. If further studies confirm this hypothesis, EFs may be useful chemical markers to assess the disposition of complex mixtures in laboratory animals and to evaluate past exposures in human populations (Supported by ES 012475 and ES 07380 from NIH; this abstract does not necessarily reflect USEPA policy).

Key words: PCB, Aroclor, Chlorofen, Enantiomeric fraction