HIGHLY CARBOXYLATED PORPHYRIN CONCENTRATION - A BIOCHEMICAL MARKER OFPCB EXPOSURE IN HERRING-GULLS

Our previous studies showed that the concentration of highly, carboxyl ated porphyrins (HCPs) was higher in livers of herring grills (Larus a rgentatus) from the Great Lakes than in livers of herring gulls from a relatively uncontaminated area of the Atlantic coast of Canada. Since there are relatively few causes of elevated HCPs other than exposure to certain halogenated aromatic hydrocarbons (HAHs), we suggested that HCP concentration might offer promise as a biochemical marker of HAH exposure in herring gulls. We did not confirm if, or identify which, H AHs were the cause of elevated HCPs, Here Its provide evidence that po lychlorinated biphenyls (PCBs) are a likely cause of HCP accumulation in hel ring gulls. HCP concentration was measured in livers of adult g ulls that were collected from several sites on the Great Lakes and fro m two reference sites. Non-polar extracts prepared from the livers wer e assayed for porphyrinogenic potency in a chicken embryo hepatocyte ( CEH) bioassay, and analyzed for concentrations of various HAHs, includ ing PCBs, There was a good linear con elation between (a) liver HCP co ncentration and porphyrinogenic potency of liver extracts, and (b) liv er HCP and PCB concentration. Congener-specific analysis suggested tha t the mono-ol tho substituted PCB congeners 2,3,3',4,4'-pentachlorobip henyl (PCB 105) and 2,3',4'5-pentachlorobiphenyl (PCB 118) were the co ngeners which contributed most to elevated HCPs in gull livers. We con clude that HCP concentration is a good biochemical marker of PCB expos ure in herring gulls. (C) 1998 Elsevier Science Ltd. All rights reserv ed.