Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada.
Environ Toxicol Chem. 2012 Nov;31(11):2445-55. doi: 10.1002/etc.1963. Epub 2012 Sep 7.
Polychlorinated biphenyl (PCB) biomagnification was characterized in a harbor seal food web in the Strait of Georgia, British Columbia, Canada. Trophic magnification factors (TMFs) for PCBs averaged 3.6, with a range of 0.7 to 9.4. The TMFs for individual congeners correlated with log K(OW) (r(2) = 0.56, p < 0.001), reflecting the role that physicochemical properties play in driving the biomagnification of PCBs in marine food webs. However, TMFs differed among PCB structure activity groups, clearly indicating an additional role for metabolic transformation of certain PCBs. The known feeding preferences of harbor seals enabled the calculation of trophic level-adjusted biomagnification factors (BMF(TL)) for PCBs in this species, which averaged 13.4 and ranged from 0.2 to 150.6. Metabolic transformation in seals explained some of the variation in congener-specific biomagnification, with lower BMF(TL) values for PCB congeners with meta- and parachlorine unsubstituted positions. Principal components analysis revealed the distinct roles played by trophic level, log K(OW), and metabolic transformation in explaining the notable differences in PCB patterns among harbor seals, their pups, and their prey. In the present study, the authors estimate there to be approximately 76 kg of PCBs in the biota of the Strait of Georgia, of which 1.6 kg is retained by harbor seals.
多氯联苯 (PCB) 在不列颠哥伦比亚省乔治亚海峡的海豹食物网中表现出生物放大作用。PCB 的营养放大因子 (TMF) 的平均值为 3.6，范围为 0.7 至 9.4。个别同系物的 TMF 与 log K(OW) 相关 (r²=0.56，p<0.001)，反映了物理化学性质在驱动海洋食物网中 PCB 的生物放大作用中的作用。然而，TMF 在 PCB 结构活性组之间存在差异，这清楚地表明某些 PCB 的代谢转化在其中发挥了额外的作用。已知的港湾海豹的摄食偏好使我们能够计算该物种中 PCB 的营养级调整生物放大因子 (BMF(TL))，其平均值为 13.4，范围为 0.2 至 150.6。海豹体内的代谢转化解释了同系物特异性生物放大的部分变异，具有未取代间位和对位氯的 PCB 同系物的 BMF(TL) 值较低。主成分分析揭示了营养水平、log K(OW) 和代谢转化在解释港湾海豹、其幼崽和猎物之间 PCB 模式的显著差异方面所起的不同作用。在本研究中，作者估计在乔治亚海峡的生物群中大约有 76 千克的 PCB，其中 1.6 千克被港湾海豹保留。
