Department of Biology, University of Louisiana at Lafayette, P.O. Box 43602, Lafayette, LA, 70504, USA.
Environ Sci Pollut Res Int. 2017 Aug;24(23):19076-19085. doi: 10.1007/s11356-017-9553-9. Epub 2017 Jun 28.
Pollution-induced community tolerance (PICT) has been used to demonstrate effects of sediment contamination on microbes and meiofauna. Our study explored the potential to detect PICT in benthic macroinvertebrates of a lake with long-term mild lead (Pb) contamination. We collected macrobenthos from two areas in Caddo Lake, Texas, a control area (CO) with a mean sediment Pb level of 11 μg/g and Goose Prairie (GP) where sediment Pb levels averaged 74 μg/g. Upon return to the laboratory, we exposed macroinvertebrates to a lethal lead concentration and assessed 48-h mortality. Mortality of CO macrobenthos was significantly higher than that of GP macrobenthos, providing evidence that these communities differed in their tolerance to lead. A comparison of macrobenthos community composition between the areas showed that the GP macrobenthos lacked metal-sensitive taxa such as gastropods and amphipods (which were present at CO). Similarly, a higher proportion of the GP benthos belonged to metal-tolerant taxa such as isopods and chironomids. Thus, changes in community composition appeared to be at least partly responsible for differences in community tolerance. Our results showed that a sediment Pb concentration below effect-based sediment quality guidelines had a measurable impact on macrobenthos, thus demonstrating that results from single-species toxicity tests may underestimate impacts on communities. This study also confirms that the PICT approach with macroinvertebrates is a feasible and potentially powerful approach for detecting contaminant impacts.
污染诱导的群落容忍度（PICT）已被用于证明沉积物污染对微生物和小型后生动物的影响。我们的研究探索了在长期受到轻度铅（Pb）污染的湖泊底栖大型无脊椎动物中检测 PICT 的潜力。我们从德克萨斯州 Caddo 湖的两个区域收集了底栖大型无脊椎动物，一个是控制区（CO），其沉积物 Pb 水平平均为 11μg/g，另一个是 Goose Prairie（GP），其沉积物 Pb 水平平均为 74μg/g。回到实验室后，我们将大型无脊椎动物暴露在致死浓度的铅中，并评估了 48 小时的死亡率。CO 底栖大型无脊椎动物的死亡率明显高于 GP 底栖大型无脊椎动物，这表明这些群落对铅的耐受性存在差异。对两个区域底栖大型无脊椎动物群落组成的比较表明，GP 底栖大型无脊椎动物缺乏对金属敏感的类群，如腹足纲和端足目（在 CO 中存在）。同样，GP 底栖生物中有更高比例的属于金属耐受类群，如等足目和摇蚊科。因此，群落组成的变化似乎至少部分是导致群落耐受性差异的原因。我们的结果表明，低于基于效应的沉积物质量指南的沉积物 Pb 浓度对大型无脊椎动物有可测量的影响，因此表明单物种毒性试验的结果可能低估了对群落的影响。本研究还证实，利用大型无脊椎动物的 PICT 方法是一种可行且具有潜在强大的方法，可用于检测污染物的影响。
