A stringent environmental quality standard for zinc (Zn) has been enacted by regulators because of its toxicity to aquatic life. This study’s objective was to evaluate the variability of Zn concentrations and fluxes in the baseflow and stormflow and to estimate the contribution of Zn from point and non-point sources. By using high-resolution temporal sampling, the suspended solids (SS), iron (Fe), and Zn concentrations were measured in a small agricultural river catchment. Fe, as the natural non-point source, and Zn were evaluated using the end member mixing analysis (EMMA) to identify the source apportionment (point and non-point). The results indicate that in the baseflow, Zn mainly originated from point sources and was possibly discharged by manufacturing industries. By contrast, the non-point sources (diffuse sources) were responsible for extremely high SS, Fe, and Zn levels in the stormflow. In addition, Zn discharge during the stormflow was 93 times higher than that during the baseflow. According to the EMMA, approximately 74% of the Zn was from point sources. River management can be improved if Zn point sources are adequately treated. During a storm event, it is also important to control the particulate Zn released into the river.

中文翻译：

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受工业区影响的小型农业河流集水区的基流和暴雨流锌负荷

由于锌 (Zn) 对水生生物具有毒性，因此监管机构已针对锌 (Zn) 制定了严格的环境质量标准。本研究的目的是评估基流和风暴流中锌浓度和通量的变化，并估计点源和非点源中锌的贡献。通过使用高分辨率时间采样，在一个小型农业河流集水区测量了悬浮固体 (SS)、铁 (Fe) 和锌浓度。使用端元混合分析 (EMMA) 评估作为天然非点源的 Fe 和 Zn，以确定源分配（点和非点）。结果表明，基流中Zn主要来源于点源，可能由制造业排放。相比之下，非点源（扩散源）是造成风暴流中极高 SS、Fe 和 Zn 含量的原因。此外，暴雨流期间的锌排放量是基流期间的 93 倍。根据 EMMA，大约 74% 的锌来自点源。如果锌点源得到充分处理，河流管理可以得到改善。在风暴事件期间，控制释放到河流中的颗粒锌也很重要。