Horne M T, Finley N J, Sprenger M D
U.S. Fish and Wildlife Service, 2890 Woodbridge Ave., Edison, New Jersey 08837, USA.
Arch Environ Contam Toxicol. 1999 Oct;37(3):317-25. doi: 10.1007/s002449900520.
The community structure of a benthic macroinvertebrate assemblage in a contaminated salt marsh was evaluated as part of an ecological characterization of a former chloralkali production facility in Georgia. Sample locations were chosen based on a gradient of the primary contaminants of concern, total mercury and polychlorinated biphenyls (PCBs), primarily Aroclor 1268. Sediment concentrations of Aroclor 1268 ranged from 2.3 to 150 mg/kg dry weight, while mercury concentrations ranged from 15 to 170 mg/kg dry weight in the study area. Mercury and PCBs were determined to be co-located in the sediments. Total organic carbon composition of the sediments was negatively associated with PCB and mercury concentrations. A total of 29 benthic taxa was identified in 49 samples; replicate samples were taken at each of five sampling locations. Mean infaunal density across all sampling locations was estimated at approximately 61,000 to 234,000 organisms m(-2). Overall, polychaetes comprised 57% of the infaunal community with Manayunkia aestuarina as the dominant species. Oligochaetes, nematodes, crustacea, insects, and gastropods comprised 23.0, 18.0, 1.0, 0.7, and 0.2% of the overall benthic community, respectively. Density estimates of individual species between sampling locations showed no consistent patterns in response to pollutants. However, an analysis of higher taxonomic levels revealed some general trends. In uncontaminated areas, the benthic community was dominated by nematodes and oligochaetes, whereas moderate to highly contaminated areas were dominated by polychaetes and a smaller percentage of oligochaetes and nematodes. A trophic analysis of the same data set revealed that the community shifted from an evenly distributed percentage of surface and subsurface feeders in the uncontaminated areas to a community dominated by surface feeders in the more contaminated locations. Carnivores comprised from 0.13 to 0.90% of the trophic structure, with the percentage of carnivores generally decreasing with increasing contamination. Mercury and PCBs were bioaccumulating in representative marsh benthic invertebrates, presenting a potential source of contaminants to marsh consumers. Tissue PCB and tissue mercury concentrations were positively related to sediment PCB and mercury concentrations, respectively. A standard 14-day toxicity test using the amphipod Leptocheirus plumulosus showed no acute toxicity across the sampling locations.
作为佐治亚州一个原氯碱生产设施生态特征描述的一部分，对受污染盐沼中底栖大型无脊椎动物群落结构进行了评估。根据主要关注污染物——总汞和多氯联苯（PCBs），主要是Aroclor 1268的梯度来选择采样地点。在研究区域，Aroclor 1268的沉积物浓度范围为2.3至150毫克/千克干重，而汞浓度范围为15至170毫克/千克干重。已确定汞和多氯联苯在沉积物中共同存在。沉积物的总有机碳组成与多氯联苯和汞浓度呈负相关。在49个样本中总共鉴定出29种底栖生物分类单元；在五个采样地点中的每一个都采集了重复样本。所有采样地点的平均底内动物密度估计约为61,000至234,000个生物体/平方米。总体而言，多毛纲动物占底内动物群落的57%，其中艾氏马尼蚓为优势物种。寡毛纲动物、线虫、甲壳纲动物、昆虫和腹足纲动物分别占整个底栖生物群落的23.0%、18.0%、1.0%、0.7%和0.2%。各采样地点之间单个物种的密度估计对污染物的响应没有一致模式。然而，对更高分类水平的分析揭示了一些总体趋势。在未受污染区域，底栖生物群落以线虫和寡毛纲动物为主，而中度至高度污染区域则以多毛纲动物以及较小比例的寡毛纲动物和线虫为主。对同一数据集的营养分析表明，群落从未受污染区域中表层和亚表层取食者均匀分布的比例，转变为在污染更严重地点以表层取食者为主的群落。肉食动物占营养结构的0.13%至0.90%，肉食动物的比例通常随着污染程度的增加而降低。汞和多氯联苯在具有代表性的盐沼底栖无脊椎动物中生物累积，成为盐沼消费者潜在的污染物来源。组织中的多氯联苯和组织中的汞浓度分别与沉积物中的多氯联苯和汞浓度呈正相关。使用羽丰长足钩虾进行的标准14天毒性试验表明，各采样地点均未显示出急性毒性。
