Submitted to: Archives of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2009
Publication Date: 2/4/2010
Citation: Wang, D., Shelver, W.L., Atkinson, S., Mellish, J., Li, Q.X. 2010. Tissue Distribution of Polychlorinated Biphenyls and Organochlorine Pesticides and Potential Toxicity to Alaskan Northern Fur Seals Assessed Using PCBs Congener Specific Mode of Action Schemes. Archives of Environmental Contamination and Toxicology. 58:478-488. DOI:10.1007/s00244-009-9396-6. Interpretive Summary: This research measured 145 individual compounds collectively known as PCB in a number of tissues (blubber, brain, heart, kidney, liver, lung, muscle, and reproductive tissues) of the fur seals from St. Pauls Island in the Northern Pacific Ocean near Alaska. The seal population at this major breeding ground has shown a sharp decrease, possibly due to pollution. Also, seal meat is a food source for certain populations, and it is important to know the amount of contamination in various tissues that might be consumed. In addition, the study used the data (levels of each compound in each tissue) to test some new measures of toxicity. These toxicity indicators are critically needed to allow proper interpretation of very complex analytical data.
Technical Abstract: The concentrations of 145 polychlorinated biphenyl (PCB) congeners were measured using gas chromatography-ion trap mass spectrometry in 8 different tissues (blubber, brain, heart, kidney, liver, lung, muscle, and reproductive tissues) of 10 Alaskan northern fur seals. The mean concentrations of both PCBs and OCPs were found to be the highest in blubber (total PCBs 578 ng/g ww) and moderate in heart (total PCBs 46.9 ng/g ww;), liver (total PCBs 34.4 ng/g ww;), and kidney (total PCBs 31.2 ng/g ww). Even lower concentrations were found in muscle (total PCBs 12.7 ng/g ww), reproductive tissues (total PCBs 15.7 ng/g ww), brain (total PCBs 9.6 ng/g ww), and lung (total PCBs 4.8 ng/g ww). Because of multiple modes of toxicity and the potency differences between congeners various PCB grouping schemes have been developed and were applied to our data. Dioxin-like toxicity is measured by total PCBs-TEQ. For PCBs with dioxin-like toxicity, muscle, brain, lung, kidney, and liver have CB-118 as the major contributor whereas for blubber, CB-126 is dominant. Heart and reproductive tissues (reprod) have CB-118 and CB-126 contributing equally for total PCBs-TEQ. Brain and lung had markedly lower total PCBs-TEQ than the other tissues. Application of Neurotoxic Equivalent (NEQ), taking account of intracellular signaling pathways, showed that brain and lung have the lowest total PCBs-NEQ at 17.7 ng/g lw and 34.5 ng/g lw, respectively. These values are higher than total PCBs-NEQ of Aroclor 1268 (16 ng/g lw), which caused intracellular Ca2+ buffering in rat cerebella granule cells. The other tissues showed markedly higher total PCBs-NEQ values. McFarland’s toxicological classification indicated mixed oxidase inducers present in high amounts in most tissues. Wolff’s toxicological classification indicated estrogenic activity in the reproductive tissue that could be problematic, particularly for males, although the phenobarbital type of the enzyme inducers was found in most tissues. Moysich’s grouping showed penta- and hexa-chloroPCBs have the highest concentrations in all the tissues. This work demonstrated the importance of congener specific analysis for a variety of tissues, particularly for the toxicity evaluation.