Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, 45144, Essen, Germany.
Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, 45144, Essen, Germany.
Environ Pollut. 2021 Jan 1;268(Pt B):115884. doi: 10.1016/j.envpol.2020.115884. Epub 2020 Oct 16.
To reduce direct discharges of surface runoff to receiving waters, separate sewer systems have been implemented, with runoff retention basins (RRB) for pollutant pretreatment by sedimentation and infiltration. However, due to frequent and intense precipitation events, most RRBs are overwhelmed by runoff resulting in overflow into the receiving freshwater bodies. Hence, the present study evaluates the impact of traffic-related runoff overflow on metal concentrations in sediment and Gammarus sp. Downstream of the RRB outfall in the receiving stream. Samples were collected from the RRB, upstream (reference site) and at different distances downstream from the RRB outfall in the stream. The samples were analyzed for the presence and distribution of metals using ICP-MS. Furthermore, ecotoxicological effects of the overflow on benthic species were assessed using Lumbriculus variegatus exposed to the field sediments. Our findings reveal that overflow of the RRB results in elevated traffic-related metal concentrations in sediment and biota of the stream. Within the first 50 m downstream increased sediment metal concentrations were found. The gammarids downstream of the RRB outfall showed an increased accumulation of several metals. Similarly, the metals were found to be taken up by the endobenthic L. variegatus under laboratory conditions and the bioaccumulation pattern was related to the sediment concentrations. Bioaccumulation by both organisms is an indication that overflow of the RRB also leads to uptake of increased element amounts in organisms downstream. Laboratory-based studies addressing standard toxicity endpoints showed no clear toxic effects on growth and reproduction. However, elevated levels of metallothioneins were measured in the annelids during the test period. This indicates a physiological response induced by increased metal concentrations due to RRB overflow. Hence, the results of this study show that discharges by the RRB increase the metal concentration in the receiving stream with the possibility of adverse effects on organisms.
为了减少地表径流对受纳水体的直接排放，已采用了分流制下水道系统，并设置了径流保留区（RRB），通过沉降和渗透对污染物进行预处理。然而，由于频繁且强烈的降水事件，大多数 RRB 都被径流淹没，导致径流溢出到受纳淡水体中。因此，本研究评估了 RRB 排放口下游 RRBs 中交通相关径流溢出对沉积物和长臂虾属（Gammarus sp.）中金属浓度的影响。从 RRB、上游（参考点）和 RRB 排放口下游不同距离处的溪流中采集了样品。使用 ICP-MS 分析样品中金属的存在和分布。此外，还使用暴露于现场沉积物的颤蚓（Lumbriculus variegatus）评估了溢出对底栖物种的生态毒理学影响。我们的研究结果表明，RRB 的溢流量导致溪流沉积物和生物体内的交通相关金属浓度升高。在下游的前 50 米处发现沉积物金属浓度增加。RRB 排放口下游的长臂虾属物种积累了几种金属。同样，在实验室条件下，发现这些金属被底栖颤蚓吸收，并且生物积累模式与沉积物浓度有关。两种生物的生物积累表明，RRB 的溢流量也会导致下游生物体内元素吸收量增加。基于实验室的研究，针对标准毒性终点进行了研究，未显示出对生长和繁殖的明显毒性影响。然而，在测试期间测量到环节动物体内的金属硫蛋白水平升高。这表明由于 RRB 溢出，金属浓度升高导致了生理反应。因此，本研究结果表明，RRB 的排放增加了受纳溪流中的金属浓度，可能对生物产生不利影响。
