Zhang Jin, Hua Pei, Krebs Peter
Institute of Urban Water Management, Technische Universität Dresden, 01062 Dresden, Germany.
Chair of Water Supply Engineering, Institute of Urban Water Management, Technische Universität Dresden, 01062 Dresden, Germany.
Environ Pollut. 2017 Sep;228:158-168. doi: 10.1016/j.envpol.2017.05.029. Epub 2017 May 18.
Road-deposited sediment and its adsorbed pollutants have been regarded as significant sources of urban diffuse pollution. In this study, the solid-phase concentrations (mg/g), surface load (mg/m) and chemical fractionation of zinc (Zn), copper (Cu) and cadmium (Cd) were determined. Geo-accumulation (I) and ecological risk (RI) indexes were employed for metal risk assessment. Results show that the highest solid-phase concentrations of Zn and Cu were usually found at an industrial area. However, Cd had the highest solid-phase concentrations at a rural area, followed by a commercial area. The surface loads of Zn and Cu decreased along the city centre to city border gradient. However, Cd was distributed irregularly. In terms of chemical fractionation, the predominant components of Zn and Cd were identified in the unstable exchangeable fractions, indicating high potential ecological risks to the aquatic environments. Cu posed a comparably low risk due to the high proportions of the stable components of residual and oxidisable fractions. According to a two-dimensional hierarchical cluster analysis, Zn and Cu surface loads were dominantly influenced by the antecedent dry-weather period; Cd contents were strongly land-use type dependent. In addition, the enrichment capability was ranked as Zn > Cu > Cd determined by I index. The sampling site dependent potential ecological risk was determined as rural area (R) > commercial city centre (W) > federal highway (B) > industrial area (I) > main road (S) > secondary road (A) by the RI index.
道路沉积物及其吸附的污染物被视为城市面源污染的重要来源。本研究测定了锌（Zn）、铜（Cu）和镉（Cd）的固相浓度（mg/g）、表面负荷（mg/m）及化学形态。采用地累积指数（I）和生态风险指数（RI）对金属风险进行评估。结果表明，Zn和Cu的最高固相浓度通常出现在工业区。然而，Cd的最高固相浓度出现在农村地区，其次是商业区。Zn和Cu的表面负荷沿市中心到城市边界梯度降低。然而，Cd的分布不规则。就化学形态而言，Zn和Cd的主要成分存在于不稳定的可交换态中，表明对水环境具有较高的潜在生态风险。由于残留态和可氧化态等稳定成分占比高，Cu的风险相对较低。根据二维层次聚类分析，Zn和Cu的表面负荷主要受前期干旱天气的影响；Cd含量强烈依赖土地利用类型。此外，根据地累积指数确定的富集能力排序为Zn＞Cu＞Cd。根据生态风险指数确定的采样点潜在生态风险排序为农村地区（R）＞商业市中心（W）＞联邦公路（B）＞工业区（I）＞主干道（S）＞次干道（A）。
