GC MS ANALYSIS OF PCB CONGENERS IN BLOOD OF THE HARBOR SEAL PHOCA-VITULINA FROM SAN-FRANCISCO BAY/

Here we report a validated technique for quantifying up to 20 specific PCB congeners in 1-2 g samples of whole blood with a detection limit below 1 ng/g (ppb) wet weight. Specimens were analyzed from 14 harbor seals sampled in south San Francisco Bay, California during 1991-1992. Ratios of specific congeners to PCB-153, and other aspects of congene r pattern, agreed with published values for PCB's detected in seal blo od. PCB-153 constituted 30 percent of our Sigma PCB values. The mean S igma PCB concentration for the San Francisco Bay seals was 50 ppb, abo ut three times the average level reported for blood of captive seals f ed exclusively on fish from the Baltic's PCB-contaminated Dutch Wadden Sea. Such experimental populations have exhibited depressed reproduct ive success and impaired immune function. These findings support conce rns about the ecological effects of PCB contamination in San Francisco Bay. (C) 1998 Elsevier Science Ltd. All rights reserved.