Wolkers J, Burkow I C, Lydersen C, Dahle S, Monshouwer M, Witkamp R F
Akvaplan-niva, Tromsø, Norway.
Sci Total Environ. 1998 May 14;216(1-2):1-11. doi: 10.1016/s0048-9697(98)00131-4.
Congener specific PCB and toxaphene (polychlorinated camphene, PCC) analyses were performed in seal blubber, collected in Svalbard, Norway. The concentration, body burden and metabolic index (PCB congener concentration in seal relative to their prey) were calculated. Multiple regression analyses were carried out to evaluate the influence of age, sex, blubber (as a percentage of total body weight) and cytochrome P450 activities on PCB and PCC levels. Levels of total PCBs found were five times higher than in ringed seals from the Canadian Arctic, corresponding with the relatively high contaminant levels in the European Arctic. The dominant PCB congeners (> 70% of the total PCBs measured) were 153, 138, 99, 180 and 101. The observed PCB and PCC accumulation patterns were very similar to patterns in seals from other studies, suggesting a large resemblance in contaminant metabolism. A decrease in the relative abundance of the lower chlorinated PCBs, was associated with higher concentrations of PCB 153. Since there was no indication for selective PCB excretion by lactating females, this suggests metabolism of these PCBs in ringed seals due to xenobiotic metabolising enzymes. The metabolic index confirmed the model of persistency of the different PCBs except for congener 128 and 138. These congeners, considered persistent in seals, could to some extent be metabolised in ringed seals. However, co-elution of PCB 138 with PCB 163 and of PCB 128 with TOX 50 possibly has resulted in an underestimation of the metabolic index for these congeners. Multiple regression analyses revealed a significant positive effect of age and a negative effect of the blubber content on the PCB concentrations. Since large fluctuations of body lipids occur between seasons in pinnipeds, PCB measurements should account for the total blubber content to avoid biased results. PCBs with vicinal H-atoms in the o, m or the m, p positions showed in addition a relation with cytochrome P450 enzyme activities. Surprisingly, no effect of sex on the PCB concentrations was observed, probably because female ringed seals, unlike other pinnipeds, continue feeding during lactation. This results in only small amounts of lipid and lipid-associated contaminants being mobilised from the blubber. Consequently, contaminant excretion with the milk will be low. Toxaphene concentrations found were low compared to levels found in the Canadian Arctic. Two congeners, TOX 26 and TOX 50 were predominant (15 and 18%, respectively of total toxaphene). There was no effect of sex, age, total blubber, or cytochrome P450 activities on the toxaphene levels. There was also no correlation between toxaphene and PCB levels, which may indicate differences in exposure and metabolism between these contaminants. Toxaphenes did not bioaccumulate to any substantial extent in ringed seals.
对在挪威斯瓦尔巴群岛采集的海豹脂肪进行了同类物特异性多氯联苯（PCB）和毒杀芬（多氯莰烯，PCC）分析。计算了其浓度、体内负荷和代谢指数（海豹体内多氯联苯同类物浓度相对于其猎物的浓度）。进行了多元回归分析，以评估年龄、性别、脂肪（占总体重的百分比）和细胞色素P450活性对多氯联苯和毒杀芬水平的影响。所发现的总多氯联苯水平比加拿大北极地区的环斑海豹高出五倍，这与欧洲北极地区相对较高的污染物水平相符。主要的多氯联苯同类物（占所测总多氯联苯的70%以上）为153、138、99、180和101。观察到的多氯联苯和毒杀芬积累模式与其他研究中海豹的模式非常相似，表明污染物代谢有很大的相似性。低氯代多氯联苯相对丰度的降低与多氯联苯153浓度的升高有关。由于没有迹象表明哺乳期雌性海豹有选择性地排泄多氯联苯，这表明环斑海豹体内这些多氯联苯是通过异生物质代谢酶进行代谢的。代谢指数证实了除128和138号同类物外不同多氯联苯的持久性模型。这些在海豹体内被认为具有持久性的同类物，在环斑海豹体内可能会在一定程度上被代谢。然而，多氯联苯138与多氯联苯163以及多氯联苯128与TOX 50的共洗脱可能导致对这些同类物代谢指数的低估。多元回归分析显示年龄对多氯联苯浓度有显著的正向影响，而脂肪含量有负向影响。由于鳍足类动物的身体脂质在不同季节间波动很大，多氯联苯测量应考虑脂肪总含量，以避免结果出现偏差。在邻位、间位或间位、对位带有相邻氢原子的多氯联苯还显示出与细胞色素P450酶活性有关。令人惊讶的是，未观察到性别对多氯联苯浓度有影响，可能是因为与其他鳍足类动物不同，雌性环斑海豹在哺乳期继续进食。这导致只有少量的脂质和与脂质相关的污染物从脂肪中被调动出来。因此，通过乳汁排出的污染物将很少。与加拿大北极地区发现的水平相比，所发现的毒杀芬浓度较低。两种同类物，TOX 26和TOX 50占主导地位（分别占总毒杀芬的15%和18%）。性别、年龄、总脂肪或细胞色素P450活性对毒杀芬水平没有影响。毒杀芬与多氯联苯水平之间也没有相关性，这可能表明这些污染物在暴露和代谢方面存在差异。毒杀芬在环斑海豹体内没有大量生物累积。
