西氿流域非点源污染负荷评估与治理对策

Non-point Source Pollution Load Evaluation and Management Strategies for Xijiu Basin

通过监测太湖流域上游备用水源地西氿流域典型次降雨的降雨历时中支流河道样品水质以及降雨强度,探讨降雨过程对地表水体水质的影响,结果表明所监测次降雨对水体中污染物有冲刷携带增加和稀释的双重作用,前期冲刷携带占主导,主要营养盐浓度上升达到峰值,后期受稀释作用和地表可冲刷污染物量减少等因素影响,样品中污染物浓度变化不同步。西氿整体呈劣Ⅴ类水质,化学需氧量(COD)、总磷(TP)与总氮(TN)为该区域地表水体主要污染物。实地调研表明,非点源污染主要来源于生活污染、养殖业和种植业,近年治理工作取得一定成效。可见继续推进控源截污工程、开展专项整治并着重完善监管模式,对控制污染、保护备用水源具有重要意义。

By monitoring the water quality of tributary samples and precipitation during a typical rainfall event in the Xijiu Basin,which is the upstream backup water source of the Taihu Basin,the effects of rainfall process on the quality of ground surfaces’water body were explored.According to the results,the rainfall runoff had dual effects of adding and diluting on the pollutants in the water body.In the earlier stage of rainfall process,flushing and carrying were the main effects on the pollutants on ground surfaces,the concentrations of the main nutrients peaked.In the later stage,the pollutants’concentrations in the runoff fluctuated differently due to the dilution process and reduced flushable pollutants on ground surfaces.Overall the water quality of Xijiu basin was poorer than ClassⅤ.Chemical oxygen demand(COD),total phosphorus(TP)and total nitrogen(TN)were key pollutants in the surface water body in this area.Field survey showed that non-point pollution mainly comes from living,aquaculture and planting,recent years’work to control pollution has seen certain benefits.Therefore,it is of great significance to continue to strengthen source pollution control and interception projects,carry out special rectification,and focus on improving the regulatory modes as to control pollution and protect backup water sources.