HydroSciences Montpellier, Université Montpellier 2, UMR 5569, 34095, Montpellier Cedex 5, France.
Environ Monit Assess. 2013 Mar;185(3):2517-34. doi: 10.1007/s10661-012-2728-4. Epub 2012 Jul 31.
This paper analyzes how changes in hydrological conditions can affect the water quality of a temporary river that receives direct inputs of sewage effluents. Data from 12 spatial surveys of the Vène river were examined. Physico-chemical parameters, major ion, and nutrient concentrations were measured. Analyses of variance (ANOVA) and multivariate analyses were performed. ANOVA revealed significant spatial differences for conductivity and major ion but no significant spatial differences for nutrient concentrations even if higher average concentrations were observed at stations located downstream from sewage effluent discharge points. Significant temporal differences were observed among all the parameters. Karstic springs had a marked dilution effect on the direct disposal of sewage effluents. During high-flow periods, nutrient concentrations were high to moderate whereas nutrient concentrations ranged from moderate to bad at stations located downstream from the direct inputs of sewage effluents during low-flow periods. Principal component analysis showed that water quality parameters that explained the water quality of the Vène river were highly dependent on hydrological conditions. Cluster analysis showed that when the karstic springs were flowing, water quality was homogeneous all along the river, whereas when karstic springs were dry, water quality at the monitoring stations was more fragmented. These results underline the importance of considering hydrological conditions when monitoring the water quality of temporary rivers. In view of the pollution observed in the Vène river, "good water chemical status" can probably only be achieved by improving the management of sewage effluents during low-flow periods.
本文分析了水文条件的变化如何影响接受污水直接输入的间歇性河流的水质。对 Vène 河的 12 次空间调查数据进行了检验。测量了理化参数、主要离子和营养物浓度。进行了方差分析 (ANOVA) 和多元分析。方差分析显示，电导率和主要离子存在显著的空间差异，但营养物浓度没有显著的空间差异，尽管在污水排放点下游的站位观察到更高的平均浓度。所有参数都存在显著的时间差异。岩溶泉对污水的直接排放有明显的稀释作用。在高流量期，营养物浓度较高至中等，而在低流量期，岩溶泉直接输入下游站位的营养物浓度则从中等到较差。主成分分析表明，解释 Vène 河水质的水质参数高度依赖于水文条件。聚类分析表明，当岩溶泉流动时，整条河的水质都是均匀的，而当岩溶泉干涸时，监测站的水质则更加分散。这些结果强调了在监测间歇性河流水质时考虑水文条件的重要性。鉴于 Vène 河受到的污染，“良好的水质化学状况”可能只能通过在低流量期改善污水的管理来实现。
