Marine Biomedicine and Environmental Sciences Program, Medical University of South Carolina, 221 Fort Johnson Road, Charleston, SC 29412, USA.
Sci Total Environ. 2010 Apr 1;408(9):2163-72. doi: 10.1016/j.scitotenv.2010.01.032. Epub 2010 Feb 16.
As apex predators within coastal ecosystems, bottlenose dolphins (Tursiops truncatus) are prone to accumulate complex mixtures of persistent organic pollutants (POPs). While substantial variations in POP patterns have been previously observed in dolphin populations separated across regional- and fine-scale geographic ranges, less is known regarding the factors influencing contaminant patterns within localized populations. To assess the variation of POP mixtures that occurs among individuals of a population, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and polybrominated diphenyl ether (PBDE) concentrations were measured in blubber and milk of bottlenose dolphins resident to Sarasota Bay, FL, and principal components analysis (PCA) was used to explain mixture variations in relation to age, sex and reproductive maturity. PCA demonstrated significant variations in contaminant mixtures within the resident dolphin community. POP patterns in juvenile dolphins resembled patterns in milk, the primary diet source, and were dominated by lower-halogenated PCBs and PBDEs. A significant correlation between principal component 2 (PC2) and age in male dolphins indicated that juvenile contaminant patterns gradually shifted away from the milk-like pattern over time. Metabolically-refractory PCBs significantly increased with age in male dolphins, whereas PCBs subject to cytochrome p450 1A1 metabolism did not, suggesting that changes in male POP patterns likely resulted from the selective accumulation of persistent POP congeners. Changes to POP patterns were gradual for juvenile females, but changed dramatically at reproductive maturity and gradually shifted back towards pre-parturient profiles thereafter. Congener-specific blubber/milk partition coefficients indicated that lower-halogenated POPs were selectively offloaded into milk and changes in adult female contaminant profiles likely resulted from the offloading of these compounds during the first reproductive event and their gradual re-accumulation thereafter. Overall, these results indicate that significant variations in contaminant mixtures can exist within localized populations of bottlenose dolphins, with life history factors such as age and sex driving individual differences.
作为沿海生态系统中的顶级掠食者，宽吻海豚（Tursiops truncatus）容易积累复杂的持久性有机污染物（POPs）混合物。虽然先前在跨越区域和精细地理范围的海豚种群中观察到持久性有机污染物模式存在显著差异，但对于影响局部种群污染物模式的因素知之甚少。为了评估一个种群内个体之间发生的 POP 混合物的变化，对佛罗里达州萨拉索塔湾的宽吻海豚的鲸脂和乳汁中的多氯联苯（PCB）、有机氯农药（OCP）和多溴二苯醚（PBDE）浓度进行了测量，并使用主成分分析（PCA）来解释与年龄、性别和生殖成熟度相关的混合物变化。PCA 表明，居留海豚群体中的污染物混合物存在显著差异。幼海豚的 POP 模式与主要饮食来源的乳汁模式相似，主要由低卤代 PCB 和 PBDE 组成。雄性海豚中主成分 2（PC2）与年龄之间存在显著相关性，表明随着时间的推移，幼海豚的污染物模式逐渐偏离乳汁模式。雄性海豚中代谢抗性 PCB 随年龄显著增加，而受细胞色素 p450 1A1 代谢影响的 PCB 则没有，这表明雄性 POP 模式的变化可能是由于持久性 POP 同系物的选择性积累所致。幼雌海豚的 POP 模式变化是渐进的，但在生殖成熟时发生了巨大变化，此后逐渐恢复到产前模式。特定同系物的鲸脂/乳汁分配系数表明，低卤代 POP 被选择性地排入乳汁中，成年雌性污染物特征的变化可能是由于在第一次生殖事件中排出这些化合物，此后逐渐重新积累所致。总体而言，这些结果表明，在宽吻海豚的局部种群中可能存在显著的污染物混合物变化，而年龄和性别等生命史因素则导致个体差异。
