Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, 3800 Bø, Norway.
Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, 3800 Bø, Norway.
Sci Total Environ. 2017 May 15;586:188-196. doi: 10.1016/j.scitotenv.2017.01.199. Epub 2017 Feb 5.
Selenium (Se), mercury (Hg), and stable isotopes of nitrogen (δN) and carbon (δC) have been investigated in free-ranging brown trout (Salmo trutta) from five large lakes/hydropower reservoirs within the River Skienselva watercourse, Southern Norway. The main purpose of the study was to investigate geographical patterns of the two elements within this large catchment. We also wanted to investigate whether Hg concentration in trout were negatively associated to their Se content, hence indicating an ameliorating effect of Se on Hg bioaccumulation. Concentrations (dry weight) in trout muscle tissue ranged from 0.21 to 2.06mgHgkg and 0.96 to 2.51mgSekg. Covariance models revealed differences in fish Hg concentrations between lakes after adjusting for the significant contributions from both age and trophic levels (TL, measured as δN), whereas fish Se concentrations differed between lakes after adjusting for TL. Se showed an inverse correlation with δC signatures in trout muscle tissue, indicating increased Se uptake in pelagic feeders. Se also increased in trout in lakes towards the western part of the watercourse as well as with increasing elevation and regulation height of lakes. The inclusion of tissue Se as an explanatory variable in the Hg model was not statistically significant and increasing Se concentrations did not lead to significantly decreased mean tissue Hg concentrations in trout, after adjusting for other significant explanatory variables. Our results support previous conclusions of a muscle tissue Se concentration threshold to affect Hg concentrations in fish, and suggest that the lakes in the region most likely are too low in Se for trout to reach such a threshold concentration.
本研究调查了挪威南部斯基恩塞瓦河流域五个大型湖泊/水力发电水库中洄游褐鳟（Salmo trutta）体内的硒（Se）、汞（Hg）以及氮（δN）和碳（δC）的稳定同位素。本研究的主要目的是调查该大型集水区内这两种元素的地理分布模式。我们还想调查鳟鱼体内 Hg 浓度是否与 Se 含量呈负相关，从而表明 Se 对 Hg 生物累积有缓解作用。鳜鱼肌肉组织中的浓度（干重）范围为 0.21 至 2.06mgHgkg 和 0.96 至 2.51mgSekg。协方差模型显示，在调整年龄和营养级（TL，用 δN 表示）的显著贡献后，湖泊间鳜鱼 Hg 浓度存在差异，而在调整 TL 后，湖泊间鳜鱼 Se 浓度存在差异。Se 与鳜鱼肌肉组织中的 δC 特征呈负相关，表明浮游食者的 Se 吸收增加。在河道西部以及湖泊海拔升高和调节高度增加的湖泊中，鳜鱼中的 Se 也增加。将组织 Se 作为解释变量纳入 Hg 模型中在统计学上并不显著，并且在调整其他显著解释变量后，增加 Se 浓度并没有导致鳜鱼组织中 Hg 浓度的平均值显著降低。我们的研究结果支持之前关于肌肉组织 Se 浓度阈值会影响鱼类 Hg 浓度的结论，并表明该地区的湖泊中 Se 含量很可能太低，无法使鳜鱼达到这种阈值浓度。
