苏州市古城区降雨径流中不同形态磷的动态污染特征及初期冲刷效应

Dynamic Pollution Characteristics and Initial Flush Effect of Phosphorus in Rainfall-Runoff of the Ancient Town of Suzhou

为研究苏州古城区降雨径流中磷的污染情况,以古城区中商业区、现代住宅区、老旧住宅区、交通区及园林旅游区为研究对象,于2015年4~8月分5次采集路面降雨径流水样,采用降雨事件污染物平均浓度法和M(V)累计曲线法,分析了磷的污染特征及初期冲刷效应。结果表明,5次降雨的污染物平均浓度的平均值由大到小依次为商业区>交通区>老旧住宅区>园林旅游区>现代住宅区,除现代住宅区外,其他各功能区TP的污染物平均浓度值均超过地表水Ⅴ类标准,且TP均以PP为主要输出形态;各功能区中TP浓度随径流历时的变化规律基本相似,径流初期TP浓度较高,随后呈下降趋势,最终趋于稳定;随着径流历时的延长,商业区、老旧住宅区、园林旅游区径流中PP/TP逐渐减小,现代住宅区则相反,而交通区基本不变,一直以PP为主导;在交通区和老旧住宅区的初期冲刷效应明显,商业区和园林旅游区难以鉴定,现代住宅区则未出现。可见城市古城区各功能区的面源污染控制需区别对待。研究成果为进一步分析苏州古城区的面源污染情况奠定了基础。

In order to study the pollution of phosphorus in rainfall runoff of the ancient town of Suzhou,business district,modern residence district,old residential area,traffic area and garden tourism area in the ancient town were selected as the research objects.From April to August in 2015,5times of its pavement runoff were collected,the pollutant concentration and M（V）cumulative curve method were used to analyze the characteristics of phosphorus pollution and initial flush effect.The results show that the EMC of TP in 5rainfall runoff ranks as follows：business district〉traffic area〉old residential area 〉garden tourism area〉 modern residence district.The EMC of TP was inferior toⅤclass of surface water in each functional area,except modern residence district,and PP was the main output form of TP.The concentration of TP in each functional area is similar with the runoff duration,there exists a higher TP concentration in the earlystage rainfall,and then it appears downward trend,eventually stabilizing.The PP/TP of runoff in business district,old residential area and garden tourism area gradually reduces,but modern residence district brought out opposite,traffic area does not change basically and dominated by PP all the time.The initial flush effect of traffic area and old residential area was obvious,business district and garden tourism area were hard to be identified while the modern residence district does not occur.Therefore,diffused pollution needs to be treated differently in various functional areas of the ancient town in the city.The research results laid the foundation for further analysis of the non-point source pollution in the ancient city of Suzhou.