Sediment contamination of freshwater streams in urban areas is a recognized and growing concern. As a part of a comprehensive regional stream-quality assessment, stream-bed sediment was sampled from streams spanning a gradient of urban intensity in the Piedmont ecoregion of the southeastern United States. We evaluated relations between a broad suite of sediment contaminants (metals, current-use pesticides, organochlorine pesticides, polychlorinated biphenyls, brominated diphenyl ethers, and polycyclic aromatic hydrocarbons), ambient sediment toxicity, and macroinvertebrate communities from 76 sites. Sediment toxicity was evaluated by conducting whole-sediment laboratory toxicity testing with the amphipod Hyalella azteca (for 28 d) and the midge Chironomus dilutus (for 10 d). Approximately one-third of the sediment samples were identified as toxic for at least one test species endpoint, although concentrations of contaminants infrequently exceeded toxicity benchmarks. Ratios of contaminant concentrations relative to their benchmarks, both individually and as summed benchmark quotients, were explored on a carbon-normalized and a dry-weight basis. Invertebrate taxa measures from ecological surveys tended to decline with increasing urbanization and with sediment contamination. Toxicity test endpoints were more strongly related to sediment contamination than invertebrate community measures were. Sediment chemistry and sediment toxicity provided moderate and weak, respectively, explanatory power for the similarity/dissimilarity of invertebrate communities. The results indicate that current single-chemical sediment benchmarks may underestimate the effects from mixtures of sediment contaminants experienced by lotic invertebrates. Environ Toxicol Chem 2020;39:1219-1232. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

中文翻译：

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沉积物中的遗留物和当前使用的污染物改变了美国东南部河流中的大型无脊椎动物群落。

在城市地区，淡水流的沉积物污染已成为公认的问题，并且日益受到关注。作为一项全面的地区河流质量评估的一部分，从美国东南部皮埃蒙特生态区中跨越城市强度梯度的河流中抽取了河床沉积物。我们评估了来自76个地点的一系列沉积物污染物（金属，目前使用的农药，有机氯农药，多氯联苯，溴化二苯醚和多环芳烃），环境沉积物毒性和大型无脊椎动物群落之间的关系。沉积物毒性通过对两栖类透明质Hyalella azteca（28天）和Midge Chironomus dilutus（10天）进行全沉积物实验室毒性测试来评估。尽管污染物的浓度很少超过毒性基准，但至少有一个测试物种终点的沉积物样本中约有三分之一被确定为有毒。以碳归一化和干重为基础，研究了污染物浓度相对于其基准的比率（无论是单独还是作为基准商）。随着城市化进程的加快和沉积物的污染，来自生态调查的无脊椎动物类目措施趋于减少。毒性测试终点与无脊椎动物群落措施相比，与沉积物污染的相关性更高。沉积化学和沉积物毒性分别为无脊椎动物群落的相似性/不相似性提供了中等和弱的解释力。结果表明，当前单一化学沉积物基准可能低估了无脊椎动物无脊椎动物所经历的沉积物污染物混合物的影响。Environ Toxicol Chem 2020； 39：1219-1232。出版于2020年。本文是美国政府的工作，在美国属于公共领域。