Heavy metal (HM) contamination of water bodies is caused by both first generation (industries) and second generation (distributed sources, domestic sewage, sediments) sources. We applied a multi-pronged approach to quantify the contribution of first and second generation sources to the HM load in a stream located in an industrialised catchment. We found that, despite strict regulation, first generation sources contributed significantly to the HM load (60%–80%), showing the ineffectiveness of current regulation. Domestic sewage contributed significantly to Cu, Ni, and Mn load (15%–20%). The contribution of distributed sources and sediments to HM load is insignificant. In a 24-hour cycle, HM concentrations frequently exceeded FAO’s irrigation water quality standards, with the highest concentrations observed at night. Empirically, the study highlights the continued plight of urban streams in rapidly industrialising centers and the failure to regulate first-generation sources. Methodologically, it demonstrates the importance of temporally intensive measurement of contaminant concentration and load. Policy implications include the need for ambient water quality standards, inclusion of HMs in such standards, load-based regulation, and a problem-oriented monitoring and enforcement approach.

Graphical abstract

中文翻译：

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城市河流重金属来源归属与解析的多管齐下

水体重金属污染由第一代（工业）源和第二代（分布式源、生活污水、沉积物）源造成。我们采用多管齐下的方法来量化第一代和第二代电源对位于工业化流域的河流中的重金属负荷的贡献。我们发现，尽管有严格的监管，第一代电源对 HM 负载的贡献很大（60%–80%），这表明当前监管的无效性。生活污水对铜、镍和锰负荷贡献显着（15%–20%）。分布式源和沉积物对重金属负荷的贡献微不足道。在 24 小时周期内，HM 浓度经常超过粮农组织灌溉水质标准，其中夜间浓度最高。根据经验，该研究强调了快速工业化中心城市河流的持续困境以及对第一代水源监管的失败。从方法上讲，它证明了污染物浓度和负荷的时间密集测量的重要性。政策影响包括需要制定环境水质标准、将 HMs 纳入此类标准、基于负荷的监管以及以问题为导向的监测和执行方法。

图形概要