Catchment Research Group, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom.
Environ Sci Technol. 2010 Mar 1;44(5):1860-7. doi: 10.1021/es903084m.
Stable isotope and contaminant analyses revealed differences in nutrient sources and contaminant pathways in two species of dipper, Cinclus mexicanus and Cinclus cinclus in western Canada and western Britain. We collected dipper prey and eggs from relatively pristine British Columbian rivers contrasting in the presence of salmon-derived nutrients, and rural Welsh rivers with varying food-web complexity associated with stream acidity. Enriched delta(13)C and to a lesser extent delta(15)N in American dipper eggs and prey confirmed that streams with migrating Pacific salmon were enriched with marine-derived nutrients, but overall contaminant concentrations did not differ strongly in dipper eggs between rivers with and without salmon. However dipper contaminant profiles, particularly PBDEs, mercury and SigmaDDTs, were related to delta(13)C, reflecting the marine influence and greater fish consumption at salmon sites. Irrespective of catchment influences and despite feeding at a higher trophic level, American dipper eggs (n = 17) contained lower levels of organohalogens than Eurasian dippers (n = 37), but with similar PCB (153 and 138) and PBDE (47 and 99) congeners dominanating. Eurasian dipper eggs from circumneutral streams contained more dieldrin, SigmaDDT and Sigmahexachlorocyclohexanes while Sigmachlordanes, mirex, SigmaPBDEs and SigmaPCBs predominated at acid sites. Our data reveal how dippers indicate contaminant levels and sources under contrasting conditions at scales ranging from local to intercontinental, but local environmental conditions apparently alter feeding ecology and exposure pathways even in these closely related species.
稳定同位素和污染物分析表明，在加拿大西部和英国西部，两种河乌，即墨西哥河乌和普通河乌，的营养物质来源和污染物途径存在差异。我们从相对原始的不列颠哥伦比亚省的河流中收集了河乌的猎物和卵，这些河流有的存在鲑鱼衍生的营养物质，而有的则没有；我们还从威尔士的农村河流中收集了猎物和卵，这些河流的食物网结构复杂程度不同，与溪流酸度有关。美洲河乌卵和猎物中富集的 δ13C 和在较小程度上的 δ15N 证实了洄游的太平洋鲑鱼使溪流中富含海洋衍生的营养物质，但总体而言，鲑鱼存在与否并没有强烈影响河乌卵中的污染物浓度。然而，河乌的污染物特征，特别是多溴二苯醚、汞和 SigmaDDT，与 δ13C 有关，反映了海洋的影响以及鲑鱼栖息地更高的鱼类摄食量。无论集水区的影响如何，尽管美洲河乌处于较高的营养级，但其卵（n = 17）中的有机卤化物含量低于欧亚河乌（n = 37），但 PCB（153 和 138）和多溴二苯醚（47 和 99）同系物的含量相似。来自中性溪流的欧亚河乌卵中含有更多的狄氏剂、SigmaDDT 和 Sigma六氯环己烷，而在酸性溪流中则含有更多的 Sigma氯丹、灭蚁灵、Sigma 多溴二苯醚和 SigmaPCBs。我们的数据揭示了河乌如何在从局部到洲际的不同尺度上指示在对比条件下的污染物水平和来源，但当地的环境条件显然会改变这些密切相关的物种的摄食生态和暴露途径。
