Irani Tayebeh, Mostafazadeh Raoof, Mousavi Moghanjoghi Saeid
Department of Range and Watershed Management, Faculty of Natural Resources, Urmia University, Urmia, Iran.
Department of Natural Resources and Member of Water Management Research Center, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, 5619911367, Iran.
Sci Rep. 2025 Aug 12;15(1):29583. doi: 10.1038/s41598-025-14982-1.
Water quality monitoring is essential for understanding ecosystem health and guiding effective water management strategies. In particular, water quality indices (WQI) are crucial tools for assessing the status of surface water bodies, providing a simplified measure of water quality across various parameters along sequential monitoring stations along a river system. This study aims to assess the spatial and temporal variations in water quality along the Little Zab River in northwestern Iran, using the Iranian Water Quality Index (IRWQI). This study examines water quality at four sequential monitoring stations along the river using the IRWQI, incorporating critical water quality parameters. Data for the analysis were collected from 2015 to 2024 and analyzed using non-parametric tests, including Kruskal-Wallis, to detect significant variations in water quality across the monitoring stations. According to the results, water quality varies across the stations. Water quality varies across stations. The upstream Mirabad-Upland station has a low IRWQI (56.51) due to wastewater from Chaku village. It improves at Grzhal-Bridge (60.04) via self-purification but declines at Nalas (57.35) due to pollution from Vavan village and agriculture. Sardasht-Dam records the highest IRWQI (64.46), likely benefiting from self-purification and cleaner inflows. Mirabad-Upland has "Fairly Good" to "Moderate" water quality. Grzhal-Bridge improves slightly, with some "Good" and "Very Good" cases, but occasional "Bad" levels. Nalas declines to mostly "Bad" and "Fairly Bad," likely due to pollution. Sardasht-Dam shows partial recovery, though some "Bad" cases persist. Overall, water quality worsens downstream due to pollution and hydrological changes. The Little Zab River's water quality followed a seasonal pattern, improving in wet months and declining in dry months due to flow changes and pollutant levels, indicating the need for year-round monitoring. The results suggest that localized pollution sources, such as wastewater discharge impact water quality, particularly in upstream sections. These results indicate the need for improved pollution control.
水质监测对于了解生态系统健康状况和指导有效的水资源管理策略至关重要。特别是，水质指数（WQI）是评估地表水水体状况的关键工具，它能提供沿河流系统连续监测站的各种参数的简化水质衡量指标。本研究旨在利用伊朗水质指数（IRWQI）评估伊朗西北部小扎卜河沿线水质的时空变化。本研究使用IRWQI对沿该河的四个连续监测站的水质进行了检测，并纳入了关键水质参数。分析数据收集于2015年至2024年，并使用非参数检验（包括Kruskal-Wallis检验）进行分析，以检测各监测站水质的显著变化。根据结果，各监测站的水质有所不同。上游的米拉巴德-高地站由于查库村的废水排放，IRWQI较低（56.51）。通过自净作用，在格拉扎尔桥站（60.04）水质有所改善，但在纳拉斯站（57.35）由于瓦万村的污染和农业活动水质下降。萨尔达什特大坝站的IRWQI最高（64.46），可能得益于自净作用和更清洁的水流。米拉巴德-高地站的水质为“较好”到“中等”。格拉扎尔桥站略有改善，有一些“良好”和“非常好”的情况，但偶尔也有“差”的水平。纳拉斯站水质大多降至“差”和“较差”，可能是由于污染。萨尔达什特大坝站显示出部分恢复，不过仍有一些“差”的情况。总体而言，由于污染和水文变化，下游水质恶化。小扎卜河的水质呈现季节性模式，由于流量变化和污染物水平，在湿润月份水质改善，在干旱月份水质下降，这表明需要进行全年监测。结果表明，诸如废水排放等局部污染源会影响水质，尤其是在上游地区。这些结果表明需要加强污染控制。
