RELATIONSHIP OF POLYCHLORINATED DIBENZO-P-DIOXIN AND POLYCHLORINATED DIBENZOFURAN LEVELS TO STABLE-NITROGEN ISOTOPE ABUNDANCE IN MARINE BIRDS AND MAMMALS IN COASTAL CALIFORNIA

Levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinate d dibenzofurans (PCDFs) were determined in common murre (Uria aalge), Brandt's cormorant (Phalacrocorax penicillatus), rhinoceros auklet (Ce rorhinca monocerata), and pigeon guillemot (Cepphus columba) eggs, and Steller sea lion (Eumetopias jubatus) blubber collected from the Gulf of the Farallones National Marine Sanctuary in 1993. In addition, the samples were analyzed for stable-nitrogen isotopes (8(15)N). Of the P CDDs and PCDFs, the 2,3,7,8-TCDD (TCDD) and 2,3,7,8-TCDF (TCDF) congen ers were the most prominent in the birds. The levels of TCDD in the eg gs ranged from 0.2 to 6.6 ng/wet kg in the pigeon guillemot and Brandt 's cormorant, respectively. The TCDF ranged from 0.30 to 2.25 ng/kg in the pigeon guillemot and Brandt's cormorant eggs, respectively. Other prominent PCDD and PCDF congeners detected in all bird species were 1 ,2,3,6,7,8-HxCDD, 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, and 1,2,3,4,6,7,8- HpCDD. In the Steller sea lion the most prominent congeners were 1,2,3 ,7,8-PeCDD at 3.2 ng/kg, 2,3,7,8-TCDD at 2.9 ng/kg, OCDF at 2.2 ng/kg, 1,2,3,6,7,8-HxCDD at 1.92 ng/kg, and 1,2,3,4,7,8-HxCDF at 1.3 ng/kg. Stable-nitrogen values ranged from 16.9% in the pigeon guillemot and r hinoceros auklet to 19.8% in the Steeler sea lion.