Heavy metal concentrations during storm events in a rehabilitated industrialized catchment
Heavy metal concentrations during storm events in a rehabilitated industrialized catchment
复制标题
恢复工业化集水区风暴事件期间的重金属浓度
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
J. G. James
中科院分区：
文献类型：
--
作者：
W. Blake;R. Walsh;M. Barnsley;G. Palmer;P. Dyrynda;J. G. James
每两周或每月收集的水质数据不足以评估和模拟许多水质问题，因为风暴事件样本代表性不足或遗漏。本文研究了南威尔士州Nant‐y‐Fendrod河中重金属（Pb、Cu、Cd和Zn）的暴雨流动力学，该河受到250年金属冶炼的影响，随后又受到35年景观恢复措施的影响。针对2000年5月和2001年2月的暴雨事件（非常干燥和非常潮湿），分别分析了上游滞洪湖上方和下方河水重金属浓度的时间变化。在2000年夏季的风暴事件中，在上游站点，铅（0.150 mg l−1）和铜（0.038 mg l−1）的总金属浓度峰值出现在上升翼，而锌（1.660 mg l−1）和镉（0.006 mg l−1）的峰值出现在下降翼，分别产生顺时针和逆时针滞后环。相比之下，金属浓度，虽然在整个冬季风暴事件高，在风暴高峰期间有所稀释。Pb和Cu似乎是由快速流动过程和运输密切相关的细沉积物，而Zn和Cd被交付到渠道和湖泊溶解形式的地下渗流较慢。在2001年冬季的事件中，前期土壤水分和浅层地下水位非常高，溶解金属的渗漏源占主导地位。下游的湖泊，铅和铜的水平和悬浮泥沙高，在夏季风暴，但在冬季风暴低，建议保留与沉积的细泥沙在湖泊在后者。在冬季风暴中，锌和镉的水平较高的下游比上游的湖泊，也许是因为额外的渗流输入从周围的斜坡，未能在夏季产生影响。了解与污染源三维分布相关的前期土壤水分和地下渗流路径动态的复杂相互作用，对于模拟受污染城市集水区的重金属通量和水平非常重要。版权所有© 2003年约翰威利父子有限公司。
Water quality data collected on a fortnightly or monthly basis are inadequate for assessment and modelling of many water quality problems as storm event samples are underrepresented or missed. This paper examines the stormflow dynamics of heavy metals (Pb, Cu, Cd and Zn) in the Nant‐y‐Fendrod stream, South Wales, which has been affected by 250 years of metal smelting, followed by 35 years of landscape rehabilitation measures. For storm events of contrasting (very dry and very wet) antecedent conditions in May 2000 and February 2001, respectively, temporal changes in streamwater heavy metal concentrations above and below an in‐line flood detention lake are analysed. At the upstream site, peaks in total metal concentration were recorded on the rising limb for Pb (0·150 mg l−1) and Cu (0·038 mg l−1) but on the falling limb for Zn (1·660 mg l−1) and Cd (0·006 mg l−1) in the summer 2000 storm event, yielding clockwise and anticlockwise hysteretic loops respectively. In contrast, metal concentrations, although high throughout the winter storm event, were diluted somewhat during the storm peak itself. The Pb and Cu appear to be supplied by quickflow processes and transported in close association with fine sediment, whereas Zn and Cd are delivered to the channel and lake by slower subsurface seepage in dissolved form. In the winter 2001 event, antecedent soil moisture and shallow groundwater levels were anomalously high and seepage sources of dissolved metals dominated. Downstream of the lake, Pb and Cu levels and suspended sediment were high in the summer storm, but low in the winter storm, suggesting retention with deposition of fine sediment in the lake during the latter. In the winter storm, Zn and Cd levels were higher downstream than upstream of the lake, perhaps because of additional seepage inputs from the surrounding slopes, which failed to have an impact during summer. An understanding of the complex interplay of antecedent soil moisture and the dynamics of subsurface seepage pathways in relation to the three‐dimensional distribution of sources is important in modelling heavy metal fluxes and levels in contaminated urban catchments. Copyright © 2003 John Wiley & Sons, Ltd.