Urban Water Engineering, Luleå University of Technology, Luleå 97187, Sweden.
Urban Water Engineering, Luleå University of Technology, Luleå 97187, Sweden.
Water Res. 2022 Jun 1;216:118284. doi: 10.1016/j.watres.2022.118284. Epub 2022 Mar 11.
Metals in stormwater can be toxic to organisms, particularly when occurring in truly dissolved form (fraction <3 kDa). Here, using 153 samples collected during six rains, we investigated intra-events variations of total, dissolved and truly dissolved metal concentrations in highway runoff, and how they were affected by a stormwater treatment train, comprising a gross pollutant trap (GPT) and a bioretention system. Although intra-event variations in metal concentrations were observed in the highway stormwater, the effluent of the GPT and the effluent from the bioretention system, generally no "first flush" was observed. While total Pb, Cu and Zn concentrations were, on average, significantly reduced by the bioretention system (>76%, 79% and 94%, respectively), removal of dissolved metals was lower and truly dissolved Cd and Cu were generally not effectively removed (average removal Cd -11%, Cu 7.7%). Only for truly dissolved Zn was removal 65%. However, as with Cu, effluent Zn concentrations exceeded environmental threshold values. While Cu, Pb and Zn occurred in the highway runoff in particulate form, with average percentages of 86%, >99% and 72%, respectively, the speciation of Cu and Zn in the bioretention effluent shifted towards greater fractions of colloidal and truly dissolved metals. The GPT had no significant effect on metal concentrations and speciation.
在雨水径流中，金属可能对生物体有毒，尤其是当它们以真正溶解的形式存在时（<3 kDa 分数）。在这里，我们使用在六场降雨期间收集的 153 个样本，研究了高速公路径流中总金属、溶解金属和真正溶解金属浓度在事件内的变化，以及它们如何受到雨水处理系统的影响，该系统包括一个总污染物截留器（Gross Pollutant Trap，GPT）和一个生物滞留系统。尽管在高速公路雨水径流中观察到金属浓度的事件内变化，但 GPT 的出水和生物滞留系统的出水通常没有观察到“初期冲刷”。虽然生物滞留系统平均可将 Pb、Cu 和 Zn 的总浓度显著降低（分别为>76%、79%和 94%），但对溶解金属的去除率较低，真正溶解的 Cd 和 Cu 一般无法有效去除（Cd 去除率平均为-11%，Cu 去除率为 7.7%）。只有真正溶解的 Zn 的去除率为 65%。然而，与 Cu 一样，出水 Zn 浓度超过了环境阈值。虽然 Cu、Pb 和 Zn 以颗粒形式存在于高速公路径流中，分别占 86%、>99%和 72%，但生物滞留出水的 Cu 和 Zn 形态向胶体和真正溶解的金属的比例更大。GPT 对金属浓度和形态没有显著影响。
