城市湖泊总磷对干湿沉降和地表径流污染的响应研究

The response of urban lake total phosphorus to dry-wet depositions and surface runoff pollution

随着对水污染的深入治理,干湿沉降、地表径流等面源污染逐步成为城市湖泊最重要的污染源之一。通过对武汉市东湖流域连续4个月干湿沉降和2场次地表径流的监测,分析了湖泊水体总磷(TP)对干湿沉降和地表径流污染的响应。结果表明,东湖湿沉降TP累积通量远大于干沉降TP累积通量,这可能与降水的洗尘作用有关;低强度降雨地表径流TP质量浓度为0.74~1.59 mg/L,高强度降雨地表径流TP质量浓度为0.95~5.82 mg/L,初期地表径流TP浓度大于后期地表径流;湖泊TP浓度变化与风速、湿沉降TP通量、降雨量紧密相关,当降雨量小于20 mm时,风速是造成湖泊中TP变动的主要因素之一,当降雨量超过20 mm时,湖泊TP变化与湿沉降TP通量变化较为一致。点源污染防治与大气污染治理、城市道路清洁、城市绿化、沉水植物生态恢复等的协调治理,将是未来城市湖泊TP污染防治的重要途径。

With the in-depth treatments of water pollution,non-point sources such as dry-wet depositions and surface runoff,gradually became the most important pollutions of urban lakes.The dry-wet depositions and 2 field surface runoffs were monitoring during continuous 4-month in Wuhan East Lake to explore the responses of total phosphorus(TP)in lake to dry-wet depositions and surface runoff pollution.Results showed that TP cumulative fluxes from wet deposition was obviously higher than that of dry deposition,this might be caused by the dust cleaning effect of precipitation.The TP mass concentrations in surface runoff of low intensity rainfall was ranged 0.74-1.59 mg/L,and for surface runoff of high intensity rainfall,the TP mass concentrations was ranged 0.95-5.82 mg/L.TP concentration was greater in initial surface runoff than in later surface runoff.The TP concentration in lake water was strongly correlated with the wind speed,wet deposition TP fluxes and rainfall quantity.When the rainfall quantity was less than 20 mm,the wind speed was one of the main factors causing the changes of TP concentrations in the lake,and when the rainfall quantity exceeded 20 mm,the changes of TP concentrations in the lake were consistent with TP fluxes of wet deposition.In the future,the coordinated management of point source pollutions,air pollution control,urban road cleaning,urban greening,submerged plant ecological restoration would be an important pathway to prevent TP pollution in urban lakes.