杭州市余杭区典型农村暴雨径流污染特征

为探讨南方经济发达地区农村暴雨径流污染特征,选择杭州市余杭区的漕桥与蒲家头两个典型建制村,采集了屋顶、场院、农田和污水汇集口这4种下垫面的3次降雨过程中的径流水样,重点分析了氮、磷和重金属元素(Mn、Cu、Zn、Ni、Cr、Cd、As、Pb)浓度,对比了不同下垫面3次暴雨径流中污染物的浓度差异和年污染负荷.结果表明,在漕桥暴雨径流中,TSS、COD、NH+4-N、TP和TN的平均浓度分别为16.19、21.01、0.74、1.39和2.39 mg·L-1;在蒲家头暴雨径流汇中,TSS、COD、NH+4-N、TP和TN的平均浓度分别为3.10、15.69、0.90、0.78和3.58 mg·L-1;暴雨径流中各重金属浓度均低于国家地表水Ⅱ类标准.与地表水标准比较,漕桥和蒲家头TP的EMC分别超出地表水Ⅴ类标准1.9倍、3.5倍,TN分别超标1.8倍、1.2倍.另外,农田下垫面中的TSS和COD年污染负荷最高.

Research of the Stormwater Runoff and Pollution Characteristics in Rural Area of Yuhang District, Hangzhou

In order to investigate the pollution characteristics of stormwater runoff in the southern developed rural region, the runoff samples were collected from four different underlying surfaces during three storm events in Caoqiao and Pujia Tou, which are two typical villages and are located in Yuhang District of Hangzhou.The content of nutrition (nitrogen and phosphorus) and heavy metals (Mn, Cu, Zn, Ni, Cr, Cd, As, Pb) in the simples were analyzed, and the difference of EMC (event mean concentration) and pollution load of the contaminants in the runoff on different underlying surfaces were compared.The results showed that the EMC of TSS, COD, NH₄⁺-N, TP and TN were 16.19, 21.01, 0.74, 1.39 and 2.39mg·L^-1 in the Caoqiao, respectively;as to Pujia Tou, they were 3.10, 15.69, 0.90, 0.78 and 3.58mg·L^-1, respectively.The content of heavy metals was all lower than the national surface water quality of two type water in the runoff.Compared with the quality standards for surface water, the EMC of TP was.9 times and 3.5 times higher and TN was 1.8 times and 1.2 times higher in two areas.Besides, the pollution loads of TSS and COD were the highest in farmland.