Patiño Reynaldo, VanLandeghem Matthew M, Goodbred Steven L, Orsak Erik, Jenkins Jill A, Echols Kathy, Rosen Michael R, Torres Leticia
U.S. Geological Survey, Texas Cooperative Fish & Wildlife Research Unit and Departments of Natural Resources Management and of Biological Sciences, Texas Tech University, Lubbock, TX 79409-2120, USA.
Texas Cooperative Fish & Wildlife Research Unit, Texas Tech University, Lubbock, TX 79409-2120, USA.
Gen Comp Endocrinol. 2015 Aug 1;219:112-24. doi: 10.1016/j.ygcen.2014.12.013. Epub 2015 Jan 9.
Adult male Common Carp were sampled in 2007/08 over a full reproductive cycle at Lake Mead National Recreation Area. Sites sampled included a stream dominated by treated wastewater effluent, a lake basin receiving the streamflow, an upstream lake basin (reference), and a site below Hoover Dam. Individual body burdens for 252 contaminants were measured, and biological variables assessed included physiological [plasma vitellogenin (VTG), estradiol-17β (E2), 11-ketotestosterone (11KT)] and organ [gonadosomatic index (GSI)] endpoints. Patterns in contaminant composition and biological condition were determined by Principal Component Analysis, and their associations modeled by Principal Component Regression. Three spatially distinct but temporally stable gradients of contaminant distribution were recognized: a contaminant mixture typical of wastewaters (PBDEs, methyl triclosan, galaxolide), PCBs, and DDTs. Two spatiotemporally variable patterns of biological condition were recognized: a primary pattern consisting of reproductive condition variables (11KT, E2, GSI), and a secondary pattern including general condition traits (condition factor, hematocrit, fork length). VTG was low in all fish, indicating low estrogenic activity of water at all sites. Wastewater contaminants associated negatively with GSI, 11KT and E2; PCBs associated negatively with GSI and 11KT; and DDTs associated positively with GSI and 11KT. Regression of GSI on sex steroids revealed a novel, nonlinear association between these variables. Inclusion of sex steroids in the GSI regression on contaminants rendered wastewater contaminants nonsignificant in the model and reduced the influence of PCBs and DDTs. Thus, the influence of contaminants on GSI may have been partially driven by organismal modes-of-action that include changes in sex steroid production. The positive association of DDTs with 11KT and GSI suggests that lifetime, sub-lethal exposures to DDTs have effects on male carp opposite of those reported by studies where exposure concentrations were relatively high. Lastly, this study highlighted advantages of multivariate/multiple regression approaches for exploring associations between complex contaminant mixtures and gradients and reproductive condition in wild fishes.
2007年至2008年期间，在米德湖国家休闲区对成年雄性鲤鱼进行了一个完整繁殖周期的采样。采样地点包括一条以经处理的废水排放为主的溪流、一个接纳该溪流的湖盆、一个上游湖盆（参照点）以及胡佛大坝下游的一个地点。测量了252种污染物的个体体内负荷，并评估了包括生理学指标[血浆卵黄蛋白原（VTG）、雌二醇-17β（E2）、11-酮睾酮（11KT）]和器官指标[性腺体指数（GSI）]在内的生物学变量。通过主成分分析确定污染物组成和生物学状况的模式，并通过主成分回归对它们之间的关联进行建模。识别出了三个在空间上不同但在时间上稳定的污染物分布梯度：一种典型的废水污染物混合物（多溴二苯醚、甲基三氯生、佳乐麝香）、多氯联苯和滴滴涕。识别出了两种时空可变的生物学状况模式：一种主要模式由繁殖状况变量（11KT、E2、GSI）组成，另一种次要模式包括一般状况特征（状况因子、血细胞比容、叉长）。所有鱼类的VTG含量都很低，表明所有采样点水体的雌激素活性都很低。废水污染物与GSI、11KT和E2呈负相关；多氯联苯与GSI和11KT呈负相关；滴滴涕与GSI和11KT呈正相关。GSI与性类固醇的回归分析揭示了这些变量之间一种新的非线性关联。在GSI对污染物的回归分析中纳入性类固醇后，废水污染物在模型中变得不显著，并降低了多氯联苯和滴滴涕的影响。因此，污染物对GSI的影响可能部分是由包括性类固醇产生变化在内的生物体作用模式驱动的。滴滴涕与11KT和GSI的正相关表明，终生亚致死剂量的滴滴涕暴露对雄性鲤鱼的影响与那些暴露浓度相对较高的研究报告的影响相反。最后，这项研究突出了多元/多重回归方法在探索复杂污染物混合物与梯度以及野生鱼类繁殖状况之间关联方面的优势。
