Abstract The quality of surface and ground water is threatened by stormwater runoff, which often contains heavy metals (such as copper, lead, and zinc), polychlorinated biphenyls (PCBs), fertilizers, and pesticides. In this study, we evaluated the effects of treated stormwater from a bioinfiltration swale on the dissolved metal load in a suburban park pond in Spokane, Washington. This pond, which has a porous bed, also receives a continuous flow of municipal water (sourced from local groundwater) to maintain a constant water level. Water samples were collected from the pond and the municipal water source every two weeks from January to August, 2016. Snow and road dust were collected in January, 2016. The results indicated that snow and dust from the roadway had elevated concentrations of major ions and heavy metals relative to their counterparts in local parks. However, the treated stormwater had a negligible impact on the dissolved load of the receiving pond for several reasons. First, heavy metal concentrations were significantly lower in the treated stormwater than the original runoff indicating successful removal by the bioinfiltration swales. Secondly, the dissolved major ion concentrations in the pond water tended to mimic the temporal fluctuations in the dissolved load of the municipal water. This can be attributed to the large volume of municipal water added to the pond (~86–97%) which dilutes the treated stormwater. Furthermore, the average residence of water in the pond is short (~39 days) such that the municipal water continuously flushes the pond. These findings establish a baseline for the dissolved load of this receiving pond and suggest that a decrease in municipal water input be carefully evaluated before implementation to prevent any adverse effects on the aquatic community. Moreover, we recommend that the heavy metal loading of the bioinfiltration swale media, and composition of treated stormwater, be monitored to ensure that metal mobilization from the swales does not occur especially during de-icing events.

中文翻译：

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由市政供水和处理过的雨水供给的郊区池塘中主要离子化学和金属的控制

摘要 地表水和地下水的质量受到雨水径流的威胁，雨水径流通常含有重金属（如铜、铅和锌）、多氯联苯（PCBs）、肥料和杀虫剂。在这项研究中，我们评估了来自生物渗透洼地的处理过的雨水对华盛顿州斯波坎郊区公园池塘中溶解金属负荷的影响。这个有多孔床的池塘也接收连续的市政水流（来自当地地下水）以保持恒定的水位。2016 年 1 月至 8 月每两周从池塘和市政水源采集水样。 2016 年 1 月采集雪和道路扬尘。结果表明，与当地公园相比，道路上的雪和灰尘的主要离子和重金属浓度较高。然而，由于几个原因，处理过的雨水对接收池的溶解负荷的影响可以忽略不计。首先，处理过的雨水中的重金属浓度明显低于原始径流，表明生物渗透洼地已成功去除。其次，池塘水中溶解的主要离子浓度倾向于模仿市政水溶解负荷的时间波动。这可归因于向池塘中添加了大量市政用水（约 86-97%），稀释了处理过的雨水。此外，水在池塘中的平均停留时间很短（约 39 天），因此市政用水不断冲洗池塘。这些发现为该接收池的溶解负荷建立了基线，并建议在实施前仔细评估市政供水量的减少，以防止对水生社区产生任何不利影响。此外，我们建议监测生物渗透洼地介质的重金属含量和处理过的雨水的成分，以确保不会发生洼地中的金属迁移，尤其是在除冰事件期间。