【作者】 张晶晶；

【导师】 陈振楼； 许世远；

【作者基本信息】 华东师范大学 ， 环境科学， 2011， 硕士

【摘要】 城市降雨径流中重金属污染主要是城市地面污染物、大气颗粒物、地表灰尘等在降雨事件作用下,经冲刷进入受纳水体,造成受纳水体水质的污染。由于近年来快速的城市化进程,城市不透水面积不断增大,导致城市降雨径流中重金属污染有日益严重的趋势。本研究内容依托于国家水体污染控制与治理科技重大专项“城市黑臭河道外源阻断、工程修复与原位多级生态净化关键技术研究及示范”(2009ZX07317-006),并在此项目与国家自然科学基金项目“沿海城市河岸氮素截留效率和转化机制研究”(40971259)、上海市优秀学科带头人计划“城市河岸带对面源营养盐的生态阻控机理研究”(10XD1401600)的资助下,以上海与温州城市降雨径流为对象,研究其中Cr、Cu、Fe、Mn、Ni、Zn、Hg和As的含量,并对此作出环境评价,了解降雨径流中各重金属的污染特征、时空变化,探讨降雨强度、降雨历时、雨前干期等降雨特征对重金属污染特征的影响程度,揭示降雨径流初期冲刷效应与各因素间关系。通过温州城区重金属污染特征和负荷的研究,估算出温州城市重金属夏季污染负荷,由此为有效地管理城市非点源污染提供可靠的数据。本研究在对大量第一手数据资料进行分析的基础上得到以下几条结论：(1)本研究监测上海和温州市区7场次夏季降雨,分析表明城市降雨径流中交通干道、停车场、小区路面等下垫面径流中重金属含量较高。溶解态Fe、Mn、Ni、Zn、Hg、等重金属与pH较为相关,溶解态Cu、Fe和Mn与TSS呈线性关系。城市降雨径流过程中pH动态变化与降雨特征并无关系；TSS时间变化呈指数衰减,其浓度的高值多出现在径流初期或是最大雨强出现时刻；重金属的动态变化与降雨特征有关,雨势较小时部分重金属会随着径流过程而累积,而雨势较大时径流初期重金属动态变化与径流深动态变化一致,一旦最大雨强出现后其浓度立刻衰减。(2)上海与温州城市降雨径流交通干道径流中TSS EMC值较高,易超出污水综合排放二级标准。降雨径流中重金属中除Hg外EMC值都低于地表水Ⅲ和V类标准,其中Cu、Mn和Zn EMC值的下垫面差异较大,EMC的高值主要是出现在交通干道等人为活动较多的下垫面径流,而Hg EMC值大小与下垫面类型无关。各降雨特征中雨前干期、降雨量和降雨强度与重金属EMC值关系较大,雨前干期越长降雨径流中重金属EMC值越大,而降雨量与降雨强度越大降雨径流中重金属EMC值则越小。(3)本研究运用无量纲累积曲线对城市降雨径流中TSS和重金属进行初期冲刷效应的分析,结果表明TSS较易发生初期冲刷效应,控制降雨径流40%的累积径流量即能有效地控制TSS对下一级受纳水体的污染。除Fe、Mn和Ni外的多数重金属不易发生初期冲刷,其中Mn的FF30值最大,为51.12%,而Cr的FF30值最小,则为31.84%。降雨径流初期冲刷效应的程度主要取决于最大降雨强度出现的时间,与汇流区下垫面的类型与面积大小无关。(4)本研究探讨其他环境介质对城市降雨径流中重金属浓度的影响,包括大气干湿沉降、地表灰尘等。结果表明上海和温州市区大气颗粒物质PM10中重金属含量基本都高于该地区土壤背景值,Mn和Ni的富集因子<1,属于自然因素：Zn的富集因子>10,属于人为活动影响造成的污染。对比城市雨水与降雨径流中重金属的浓度,发现雨水中重金属对降雨径流有着一定的贡献,将研究区雨水中含金属浓度与国内外城市进行对比,得出上海和温州雨水重金属浓度是国内较低污染水平,但明显高于发达国家城市,说明雨水中重金属污染水平与经济、城市化发展水平有一定的关联。城市停车场和交通干道的地表灰尘含量较高,上海与温州地表灰尘污染程度相近,且多数重金属均呈现粒径分级效应,其中Cr、Cu、Pb和Zn最为明显。(5)本论文将“地表灰尘—雨水井口沉积物—降雨径流”作为系统进行探讨,其中Cr、Cu、Fe、Mn、Ni和Pb的含量呈递减的状态,其中递减程度最为明显的是Mn,这一方面说明这些重金属的来源具有一定的相似性,另一方面说明地表灰尘中重金属对降雨径流贡献较大,但整体的影响机制受到影响因素多且复杂并伴随着随机性,较难统一(6)通过对温州山下河和九山外河流域汇流区夏季5场次降雨事件进行监测,得到两个汇流区夏季降雨径流中Cr、Cu、Fe、Mn、Ni、Zn、Hg和As的EMCs值,结合SCS模型对汇流区径流量进行修正,利用降雨径流重金属污染负荷模型对不同下垫面夏季重金属污染负荷定量,其结果表明山下河汇流区降雨径流中Cr、Cu、Fe、Mn、Ni、Pb、Zn、Hg和As的夏季负荷为0.16 kg、0.40 kg、2.06 kg、0.69 kg、0.23 kg、1.85 kg、0.04 kg和0.35kg,而相应地九山外河汇流区夏季负荷为0.05 kg、0.43 kg、3.33 kg、3.35 kg、0.24 kg、4.10 kg、0.08 kg和0.22kg。可以看出汇流区夏季降雨径流重金属污染负荷与该汇流区面积、汇流区下垫面性质以及该下垫面径流中所携带的重金属污染物浓度都有一定的关系,结果表明九山外河汇流区降雨径流重金属污染对九山外河的影响较大。将两个汇流区夏季降雨径流重金属污染负荷按下垫面类型进行分类,山下河汇流区各下垫面贡献率由大到小顺序为：屋面>交通干道>小区路面>草地>停车场；九山外河汇流区各下垫面贡献率由大到小顺序为：小区路面>屋面>草地>交通干道>停车场。更多还原

【Abstract】 Heavy metal pollution of urban rainfall runoff was the water pollution which formed by washing urban surface pollutants, Atmospheric particulates, surface dusts etc. and informed receiving waterbodies. Since quick urbanization in recent years, the areas of impermeable surface had increased leading to serious heavy metals pollution of urban rainfall runoff. With the support of Major Science and Technology Program for Water Pollution Control and Treatment (No.2009ZX07317-006), NNSF of China (No.40971259), and Shanghai excellent entancement plan (No.10XD1401600), the pollution characters and spatio-temporal changes were studied. Besides, first flush effects of rainfall runoff were also studied to proclaim the relationship between rainfall character and heavy metal EMCs. And the resouces of heavy metal in PM10S, surface dusts and catch-basin sediments were analyzed. Using EMCs of heavy metals(Cr, Cu, Fe, Mn, Ni, Zn, Hg and As) estimated urban heavy metal load in summer in Wenzhou City to supply stable datas to management of uraban non-point source pollution.The main conclusions can be summed up as follows.1. The study monitored 7 summer rainfall events in Shanghai and Wenzhou City, the results showed that contents of heavy metals in traffic artery, parking lot and community road were higher than other underlying surface. The contents of Fe, Mn, Ni, Zn, Hg (dissolved form) were related to pH and Cu, Fe and Mn (dissolved form) related to TSS. Dynamic changes of pH were not related to rainfall charaters, the opponent to heavy metals, and the TSS one showed indexmovement when the max value appeared the beginning of rainfall runoff.2. TSS EMC of the traffic artery runoff was the highest of all the underlying surfaces and exceeded Integrated Wastewater Discharge 2 Standard easily. Heavy metal EMCs except Hg were below to Surface Water III and V Standard, which EMCs of Cu, Mn and Zn got apparent spatial variability, but Hg EMC was not related to underlying surface types. Correlation coefficient was higher among ADWP, precipitation, rainfall intensity and EMCs of heavy metals.3. It was analyzed about first flush effects of urban rainfall runoff by using dimensionless cumulative curve. The main results determined that TSS gained first flush effect easier than heavy metals. It is efficient to control water pollution by remove the first 40% runoff. Except Fe, Mn and Ni, heavy metals appeared the first flush effects hard. FF30 of Mn was 51.12% and Cr was 31.84% which was the max value and min value of FF30. The result showed the effect of first flush mainly depended on the time of max rainfall intensity.4. The study research heavy metals in other environmental mediums affecting to the on in rainfall runoff including atmospheric deposition (dry and wet), surface dust etc. Heavy metal contents of PM10 in Shanghai and Wenzhou were higher than their background value of soil environment. EF of Mn and Ni were less than 1, meaned natural resource; EF of Zn was greater than 10, meaned human interference. Compared with heavy metal contents in urban rainwater, it had relationship with the contents in rainfall runoff and contributed a lot to heavy metal contents of rainfall runoff. The contents of heavy metals in surface dusts were higher in traffic artery and parking lot. The heavy metal pollution degree of surface dust was similar in both Shanghai City and Wenzhou City.5. The trend of Cr, Cr, Fe, Mn, Ni and Pb contents decreased progressively in the system of surface dust—catch-basin sediment—rainfall runoff, especially Mn. It indicated that on one hand resource of these heavy metals were similar; on the other hand heavy metal pollutants in surface dusts contributed more. The affection machining was affected by lots of facts, presented complexity and randomness and hard to centralize.6. By means of monitoring 5 rainfall events in summer in Wenzhou City(SX catchment and JS catchment), the EMCs of Cr, Cu, Fe, Mn, Ni, Zn, Hg and As were analyzed. After correcting CN value of SCS modeling and quantifying, summer heavy metal pollution loads were estimated. The results showed that the loads of Cr, Cu, Fe, Mn, Ni, Pb, Zn, Hg and As were 0.16kg, 0.40 kg, 2.06 kg, 0.69 kg, 0.23 kg, 1.85 kg, 0.04 kg and 0.35kg in SX catchment when the JS catchment were 0.05 kg,0.43 kg, 3.33kg, 3.35kg, 0.24kg,4.10 kg,0.08 kg and 0.22kg, which means JS catchment was affected critically by rainfall runoff pollution. Contribution rate of unerlying surface in SX catchment was roof>traffic artery>community road>grassland> parking lot, and JS catchment was community road>roof>grassland>traffic artery >parking lot.更多还原