从水质变化趋势看常州市武南区域重点河流治理成效

为探究武南区域重点河流水质的变化规律、驱动因素以及河流治理成效，基于2006~2018年连续水质监测数据，综合分析了4条重点河流（太滆运河、武宜运河、武进港和永安河）水质演变趋势，并对污染较重的永安河各项水质指标进行了季节性分析和相关性分析.结果表明：2006~2018年，4条河流水质整体呈好转趋势，修正内梅罗指数分别下降36.2%，31.5%，56.4%，48.7%，受河流清淤工程影响，永安河2017年水质有所下降；4条河流氨氮浓度、总氮浓度与高锰酸盐指数下降趋势明显（P<0.05），总磷浓度则存在一定波动；永安河的总氮、氨氮和高锰酸盐指数间或存在同源关系，氨氮和总氮季节性变化明显，雨季浓度低于旱季，总磷和高锰酸盐指数没有明显季节性变化趋势；城镇化发展与产业结构由传统工业、农业向第三产业的转变均对区域水环境改善有积极作用.

Spatiotemporal trends in water quality and the effectiveness of water treatment projects for Wunan District,Changzhou

The aims of this study were to explore spatiotemporal differences in water quality of 4 main rivers (Taige River, Wuyi River, Wujin River and Yongan River) in Wunan District based on 2006~2018 water quality monitoring data, to identify the contributions of different activities on water quality parameters, to evaluate the effects of treatment projects on water quality, and to conduct seasonal and correlation analysis for the most heavily polluted river (i.e., Yongan River). The results showed that water quality of 4 rivers improved from 2006 to 2018, with the modified Nemerow index declining by 36.2%, 31.5%, 56.4% and 48.7%. Water quality of Yongan River deteriorated in 2017 due to dredging activities. The ammonia nitrogen (NH₃-N) concentration, total nitrogen (TN) concentration and permanganate index significantly decreased year by year (P<0.05), but the total phosphorus (TP) concentrations fluctuated across the same period. The correlation analysis indicated that NH₃-N, TN and permanganate index may stem from the same sources. NH₃-N and TN exhibited an obvious seasonal variation, but no clear trend was observed for TP and permanganate index. Overall, increased urbanization, decreased traditional industry, and decreased agricultural activity had positive effects on improving water quality in Wunan District.