Background

Rivers receive water and associated organic micropollutants from their entire catchment, including from urban, agricultural and natural sources, and constitute an important environmental component for catalyzing pollutant turnover. Environmental removal processes were extensively investigated under laboratory conditions in the past but there is still a lack of information on how organic micropollutants attenuate on the catchment scale. The aim of this study was to describe the chemical and toxicological profile of a 4th order river and to characterize in-stream processes. We propose indicator chemicals and indicator in vitro bioassays as screening methods to evaluate micropollutant input and transport and transformation processes of the chemical burden in a river. Carbamazepine and sulfamethoxazole were selected as indicators for dilution processes and the moderately degradable chemicals tramadol and sotalol as indicators for potential in-stream attenuation processes. The battery of bioassays covers seven environmentally relevant modes of action, namely estrogenicity, glucocorticogenic activity, androgenicity progestagenic activity and oxidative stress response, as well as activation of the peroxisome proliferator-activated receptor and the aryl hydrocarbon receptor, using the GeneBLAzer test battery and the AhR-CALUX and AREc32 assays.

Results

Both approaches, targeted chemical analysis and in vitro bioassays, identified a wastewater treatment plant (WWTP) as a major input source of organic micropollutants that dominantly influenced the water quality of the river. Downstream of the WWTP the amount of detected chemicals and biological effects decreased along the river flow. The organic indicator chemicals of known degradability uncovered dilution and potential loss processes in certain river stretches. The average cytotoxic potency of the river water decreased in a similar fashion as compounds of medium degradability such as the pharmaceutical sotalol.

Conclusions

This study showed that the indicator chemical/indicator bioassay approach is suitable for identifying input sources of a mixture of organic micropollutants and to trace changes in the water quality along small rivers. This method forms the necessary basis for evaluating the natural attenuation processes of organic micropollutants on a catchment scale, especially when combined with enhanced sampling strategies in future studies.

中文翻译：

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将体外报告基因生物测定与化学分析相结合，以评估德国西南部阿默河沿岸的水质变化。

背景

河流从其整个流域（包括城市、农业和自然资源）接收水和相关的有机微污染物，并构成催化污染物周转的重要环境成分。过去在实验室条件下对环境去除过程进行了广泛的研究，但仍然缺乏关于有机微污染物如何在流域范围内衰减的信息。本研究的目的是描述 4 级河流的化学和毒理学特征，并描述河流过程的特征。我们建议将指示化学品和指示剂体外生物测定作为筛选方法，以评估河流中微污染物的输入以及化学负荷的运输和转化过程。选择卡马西平和磺胺甲恶唑作为稀释过程的指标，选择可适度降解的化学品曲马多和索他洛尔作为潜在的流内衰减过程的指标。生物测定系列涵盖七种与环境相关的作用模式，即雌激素、糖皮质激素活性、雄激素孕激素活性和氧化应激反应，以及过氧化物酶体增殖物激活受体和芳烃受体的激活，使用 GeneBLAzer 测试电池和AhR-CALUX 和 AREc32 检测。

结果

这两种方法，有针对性的化学分析和体外生物测定，都将废水处理厂 (WWTP) 确定为主要影响河流水质的有机微污染物的主要输入源。在污水处理厂下游，检测到的化学物质和生物效应的数量随着河流的流动而减少。已知可降解性的有机指示化学品揭示了某些河流段的稀释和潜在损失过程。河水的平均细胞毒效力下降的方式与中等降解性的化合物（如药物索他洛尔）相似。

结论

这项研究表明，指示化学/指示生物测定方法适用于识别有机微污染物混合物的输入源，并追踪小河流沿线的水质变化。该方法为评估流域范围内有机微污染物的自然衰减过程奠定了必要的基础，特别是在未来研究中与增强的采样策略相结合时。