Besser J M, Brumbaugh W G, May T W, Church S E, Kimball B A
U.S. Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, Missouri 65201, USA.
Arch Environ Contam Toxicol. 2001 Jan;40(1):48-59. doi: 10.1007/s002440010147.
The water quality, habitats, and biota of streams in the upper Animas River watershed of Colorado, USA, are affected by metal contamination associated with acid drainage. We determined metal concentrations in components of the food web of the Animas River and its tributaries-periphyton (aufwuchs), benthic invertebrates, and livers of brook trout (Salvelinus fontinalis)-and evaluated pathways of metal exposure and hazards of metal toxicity to stream biota. Concentrations of the toxic metals cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in periphyton, benthic invertebrates, and trout livers from one or more sites in the upper Animas River were significantly greater than those from reference sites. Periphyton from sites downstream from mixing zones of acid and neutral waters had elevated concentrations of aluminum (Al) and iron (Fe) reflecting deposition of colloidal Fe and Al oxides, and reduced algal biomass. Metal concentrations in benthic invertebrates reflected differences in feeding habits and body size among taxa, with greatest concentrations of Zn, Cu, and Cd in the small mayfly Rhithrogena, which feeds on periphyton, and greatest concentrations of Pb in the small stonefly Zapada, a detritivore. Concentrations of Zn and Pb decreased across each trophic linkage, whereas concentrations of Cu and Cd were similar across several trophic levels, suggesting that Cu and Cd were more efficiently transferred via dietary exposure. Concentrations of Cu in invertebrates and trout livers were more closely associated with impacts on trout populations and invertebrate communities than were concentrations of Zn, Cd, or Pb. Copper concentrations in livers of brook trout from the upper Animas River were substantially greater than background concentrations and approached levels associated with reduced brook trout populations in field studies and with toxic effects on other salmonids in laboratory studies. These results indicate that bioaccumulation and transfer of metals in stream food webs are significant components of metal exposure for stream biota of the upper Animas River watershed and suggest that chronic toxicity of Cu is an important factor limiting the distribution and abundance of brook trout populations in the watershed.
美国科罗拉多州阿尼马斯河上游流域溪流的水质、栖息地和生物区系受到与酸性排水相关的金属污染影响。我们测定了阿尼马斯河及其支流食物网各组成部分——周丛生物（附着生物）、底栖无脊椎动物和溪鳟（红点鲑）肝脏中的金属浓度，并评估了金属暴露途径以及金属毒性对溪流生物区系的危害。来自阿尼马斯河上游一个或多个地点的周丛生物、底栖无脊椎动物和鳟鱼肝脏中的有毒金属镉（Cd）、铜（Cu）、铅（Pb）和锌（Zn）浓度显著高于参考地点。酸性水与中性水混合区下游地点的周丛生物中铝（Al）和铁（Fe）浓度升高，反映了胶体铁和铝氧化物的沉积，且藻类生物量减少。底栖无脊椎动物中的金属浓度反映了不同分类群在摄食习性和体型大小上的差异，以周丛生物为食的小型蜉蝣Rhithrogena中锌、铜和镉的浓度最高，而小型食碎屑石蝇Zapada中铅的浓度最高。锌和铅的浓度在每个营养级联中都有所下降，而铜和镉的浓度在几个营养级上相似，这表明铜和镉通过饮食暴露的转移效率更高。与锌、镉或铅的浓度相比，无脊椎动物和鳟鱼肝脏中的铜浓度与对鳟鱼种群和无脊椎动物群落的影响更为密切相关。阿尼马斯河上游溪鳟肝脏中的铜浓度大大高于背景浓度，接近实地研究中与溪鳟种群减少相关的水平以及实验室研究中对其他鲑科鱼类产生毒性影响的水平。这些结果表明，溪流食物网中金属的生物累积和转移是阿尼马斯河上游流域溪流生物区系金属暴露的重要组成部分，并表明铜的慢性毒性是限制该流域溪鳟种群分布和数量的一个重要因素。
