昆明主城区城市地表径流污染特征分析

昆明市位于滇池上游,城市地表径流污染负荷对滇池水质具有直接影响。通过对昆明主城区内不同功能区12个监测点7次降雨径流过程水样的采集与分析,研究了昆明主城区城市地表径流污染特征。结果表明,昆明主城区城市地表径流中TSS、COD、TN和TP的多场降雨平均浓度分别为182.8、138.2、2.37和0.43 mg/L。不同功能区的地表径流水质存在显著差异(p<0.05);各功能区径流污染负荷顺序为:公路区>商业区>住宅区>文教区;不同功能区单场降雨径流水质动态变化规律是:污染物浓度在降雨径流初期相对较高,中后期浓度快速下降,并逐渐趋于稳定;地表利用功能、降雨特征和交通流量是影响城市地表径流水质的主要因素;城市地表径流中COD、TN、TP与TSS之间有较好的相关性,说明大部分的污染物质是以颗粒吸附态存在。     

西安市城市主干道路面径流初期冲刷效应

以西安市城市主干道南二环太白路高架桥为路面径流采样区域,采用人工等时间间隔采样方法,在桥梁排水立管对2010年9—11月的3场径流事件进行全程采样,测试径流过程SS、COD、溶解性COD、NH3-N、Pb、溶解性Pb、Zn和溶解性Zn的浓度变化,研究路面径流的初期冲刷效应及其影响因素。结果表明,西安市城市主干道路面径流污染严重,降雨数小时后的末期径流仍具有较高的污染水平;径流过程污染物浓度变化规律与其赋存形态有关,SS、COD、Pb等以颗粒态为主的污染物的浓度随雨强变化剧烈波动,NH3-N、溶解态COD、溶解态Zn等以溶解态为主的污染物浓度变化受雨强影响较小,随径流过程呈逐渐减小趋势;路面径流初期冲刷现象并非普遍存在,与污染物的赋存状态和场次降雨特征密切相关,溶解态污染物易于出现初期冲刷现象,颗粒态污染物是否出现初期冲刷与场次降雨特征有关;测试的3场径流事件初期30%的径流携带的SS、COD、溶解性COD、NH3-N、Pb、Zn和溶解性Zn的负荷占场次径流总负荷的比例分别为21.8%～50.0%、25.5%～49.3%、36.3%～52.6%、52.6%～66.7%、26.8%～45.0%、27.2%～63.4%和36.2%～62.6%,表明仅对初期径流进行治理无法实现对西安市路面径流污染的有效控制。     

深圳大工业区初期雨水水质污染特征研究

为研究深圳大工业区初期雨水水质污染特征,分别选择深圳大工业区6个功能区作为监测点监测初期雨水中污染物浓度。结果表明:深圳大工业区居住区和商业区初期雨水COD污染最严重,COD最高分别达到1 467.00、1 333.00mg/L;出口加工区及高科技工业和现代物流业区域的初期雨水TN、TP浓度略低于其他区域。初期雨水中COD、氨氮、TP浓度与SS浓度存在线性相关关系,而TN浓度与SS浓度的线性相关性较差,不同区域随降雨历时变化规律波动各异。深圳大工业区附近河流SS、COD、TN、氨氮、TP浓度受初期雨水影响较大。     

中小城市不同功能区降雨径流氮污染特征及其对水体的影响

研究了典型中小城市滨州的不同功能区降雨径流中的氮污染特征及其对水体污染的影响。结果表明,滨州城区不同功能区降雨径流总无机氮(TIN)、氨氮、硝酸盐氮和亚硝酸盐氮质量浓度分别为0.22~10.19、0.01~1.73、0~6.61、0~1.84mg/L。部分降雨径流样品的TIN已经超过了《地表水环境质量标准》(GB 3838—2002)中总氮的Ⅴ类水体标准限值。各形态无机氮浓度在不同功能区存在显著差异。TIN浓度均值表现为:农业区文教区工业区居住区商业区交通要道。降雨径流中的氮元素主要以硝酸盐氮形式存在。河流中TIN主要来自氨氮,其浓度水平与降雨径流相当。因此,降雨径流的氮污染对河流有重要影响,应引起重视。     

盐城市不同功能区地表灰尘重金属污染特征及评价

为了解盐城市不同功能区地表灰尘中重金属污染特征,以工业区、交通区、居民区、商业区、学校区、公园区的地表灰尘作为研究对象,分析地表灰尘中重金属的含量分布及氮磷、有机质的含量变化,并以此为基础,对重金属的生态风险进行评价,探索重金属污染的成因与来源,为城市的地表灰尘污染防治提供理论依据。结果表明:(1)工业区地表灰尘中总氮、总磷最低;公园区和学校区地表灰尘中总氮最高,分别达到2.03、2.43g/kg,公园区地表灰尘中总磷最高,达到1.59g/kg。(2)地表灰尘中有机质呈现出和总氮、总磷一致的趋势,同样是工业区地表灰尘中有机质最低,公园区地表灰尘中有机质最高(34.0g/kg)。(3)地表灰尘中重金属和总氮、总磷、有机质总体呈现负相关关系,公园区地表灰尘中重金属最低,工业区地表灰尘中重金属最高。各个功能区地表灰尘中重金属全部高于土壤背景值。(4)地表灰尘中不同重金属元素的单因子污染指数依次为CdCuPb;不同功能区地表灰尘中重金属综合污染指数依次为工业区交通区居民区学校区商业区公园区,呈中污染(除公园区、商业区呈轻污染外)。     

沈阳市环境空气不同功能区二噁英含量与暴露风险分析

以沈阳市不同功能区为研究对象,进行不同功能区的二噁英含量与暴露风险分析.研究表明:沈阳市不同功能区的二噁英质量浓度大小顺序为工业区＞居民区＞文化区＞商业区＞公园＞风景区；6个功能区均检测出多氯二苯并二噁英(PCDDs)、多氯二苯并呋喃(PCDFs)和多氯联苯(PCB)3种污染物,除风景区外,PCDFs所占比例最大,PCDDs居第二位,PCB所占的比例最小；毒性当量的计算结果表明,不同功能区的二噁英毒性当量浓度与其质量浓度大小顺序一致；呼吸暴露量计算结果表明,儿童的呼吸暴露量高于成人,说明儿童受到空气二噁英的呼吸暴露风险更大.     

不同地表雨水径流冲刷特性分析

选择北京市某城区典型地表(校园、自行车道、商业街和高架桥)的雨水径流作为研究对象,系统分析了不同地表雨水径流的冲刷特性。分析结果表明:不同地表初期冲刷现象都比较明显,控制不同地表20%的初期雨水可以削减污染物总量的40%～60%,高架桥初期雨水径流中COD、SS和TP浓度最高,校园初期雨水径流中TN浓度最高。不同地表雨水径流的水质优劣顺序为:校园>商业街>自行车道>高架桥。校园和自行车道在整个降雨过程中D50和D90粒径大小相近,分别为30μm和50μm左右,且变化幅度都较小。高架桥和商业街在雨水径流初期D50和D90粒径有明显减小,但后期均出现较大幅度的波动,其粒径明显大于校园和自行车道。上述研究成果对于城市不同地表雨水径流污染控制和场地开发具有重要意义。     

城市典型屋面径流的排污特征

对城市中典型的2种材料(油毡和水泥)屋面降雨径流中颗粒物(SS)、氮(N)和磷(P)污染物排放特征进行了研究。结果表明,屋面径流中颗粒物主要是以10~100μm粒径范围的颗粒物为主(约占75%),氮主要是以溶解态形式排放(80%~95%),且主要形式是以硝态氮和氨态氮为主,水泥屋面增加了径流中硝态氮的比例,而沥青屋面增加了氨态氮和溶解态有机氮的比例。而磷主要是以颗粒物形态排放(约占40%~70%,平均57.5%),且主要结合10~50μm粒径范围的颗粒物。去除10~50μm粒径颗粒物可以降低屋面径流中50%颗粒物和47.9%磷的排放,而氮却需采用不同处理方法。同时,EC和TSS与TN和TP相关关系表明,EC和TSS可分别作为屋面降雨径流溶解态氮和颗粒态磷污染程度检测和评价指示指标。研究结果为有效地去除降雨径流中污染物、降低城市面源污染对水环境的影响,提供了一定的科学依据。     

前期晴天数对不同材质屋面径流污染特征的影响

以城市典型屋面材质(油毡、塑钢、瓦)为研究对象,通过人工模拟降雨考察不同前期晴天数对不同材质屋面径流污染特征的影响。结果表明,不同材质屋面径流中悬浮物(SS)、化学需氧量(COD)、总磷(TP)和总氮(TN)的场次降雨径流平均浓度由大到小都依次为油毡屋面、瓦屋面和塑钢屋面。不同材质屋面径流中重金属的场次降雨径流平均浓度各不相同。总体而言,污染物浓度随前期晴天数增加而增大,主要是小粒径的颗粒物体积分数增加,而大粒径的颗粒物体积分数反而减小。屋面径流中SS是COD、TP和重金属的主要载体,污染物与小粒径的颗粒物相关性更高,因此要想控制屋面径流中的COD、TP和重金属,关键是控制细小的颗粒物。     

基于城市下垫面和雨污排放口监测方法的内江市建成区城市面源对比分析

分别用基于城市下垫面和雨污排放口监测方法对内江市建成区城市面源进行3次全过程降雨监测。结果表明:(1)屋面5种污染物3次降雨的次降雨径流平均浓度(EMC)平均值均低于其他监测点位。雨污排放口氨氮、总氮的浓度总体高于其他监测点位。交通道路,尤其是交通主干道,由于受人类活动影响大,各种污染物浓度都普遍较高。(2)交通主干道的降雨初始冲刷效应(FFE)最明显,其次为一般道路、庭院、屋面;雨污排放口的FFE很不明显。(3)两种监测方法相对误差最大的是9月6日总磷的估算结果,为14.75%;两种监测方法所得的COD相对误差最大,为9.10%~14.30%,相对误差最小的为氨氮。(4)比例推算法与基于城市下垫面监测方法的相对误差为1.3%~19.2%;排放强度法与基于城市下垫面监测方法的相对误差为0.7%~25.4%。     

河水受百年一遇大旱后城市降雨径流的污染与治理

2009年入秋至2010年春,中国西南地区发生了百年一遇的特大旱灾。为探讨河水受百年一遇大旱后降雨径流污染的状况,对昆明典型交通干道路面的降雨径流和河水水质进行了监测,分析了大旱后降雨径流污染的严重性和对河水水质的影响,并考察了曝气塘—浮石床水平潜流人工湿地复合系统处理大旱后由城市降雨径流污染导致的重污染河水的效能。结果表明,大旱后的前3场降雨径流污染程度较正常雨季降雨径流污染程度严重,SS、COD、TN及TP浓度平均高出1.3倍。大旱后的前3场降雨径流溢流会对河流造成严重污染。该复合系统在塘调蓄—循环处理运行工况下能有效处理大旱后的重污染河水,对SS、COD、TP、TN和NH4+-N的平均去除率分别为98%、90%、96%、60%和90%,出水均达《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准。     

Speciation distribution and mass balance of copper and zinc in urban rain, sediments, and road runoff

Heavy metal pollution in road runoff had caused widespread concern since the last century. However, there are little references on metal speciation in multiple environmental media (e.g., rain, road sediments, and road runoff). Our research targeted the investigation of metal speciation in rain, road sediments, and runoff; the analysis of speciation variation and mass balance of metals among rain, road sediments, and runoff; the selection of main factors by principal component analysis (PCA); and the establishment of equation to evaluate the impact of rain and road sediments to metals in road runoff. Sequential extraction procedure contains five steps for the chemical fractionation of metals. Flame atomic absorption spectrometry (Shimadzu, AA-6800) was used to determine metal speciation concentration, as well as the total and dissolved fractions. The dissolved fractions for both Cu and Zn were dominant in rain. The speciation distribution of Zn was different from that of Cu in road sediments, while speciation distribution of Zn is similar to that of Cu in runoff. The bound to carbonates for both Cu and Zn in road sediments were prone to be dissolved by rain. The levels of Cu and Zn in runoff were not obviously influenced by rain, but significantly influenced by road sediments. The masses for both Cu and Zn among rain, road sediments, and road runoff approximately meet the mass balance equation for all rainfall patterns. Five principal factors were selected for metal regression equation based on PCA, including rainfall, average rainfall intensity, antecedent dry periods, total suspended particles, and temperature. The established regression equations could be used to predict the effect of road runoff on receiving environments.     

山地城市暴雨径流污染特性及控制对策

为了解山城重庆的暴雨径流污染特性,充实国内仍然薄弱的基础资料,对4种用地类型的4场暴雨进行了监测,测试指标包括TSS、COD、TP、TN和NH3-N。结果表明,对于坡度2.5%的交通干道和坡度30%的校园人行道,从污染物浓度降幅的角度考虑初期径流的控制量应分别为2～3 mm和1.8 mm。随降雨时间的延长,路面污染物浓度迅速降低,坡度越大,降低速率越快。对于平均浓度,校园屋顶和草坪的各污染物浓度均达到地表水环境质量Ⅴ类标准(总氮和氨氮除外)。交通干道和校园人行道的总磷平均浓度也满足地表水环境质量Ⅴ类标准,但2种下垫面的COD、TN和氨氮平均浓度分别超出地表水环境质量Ⅴ类标准的2～8倍、1.9～3.1倍和1.9～4.3倍。对于交通干道,场次降雨径流的总氮、总磷和氨氮平均浓度与初期浓度的比值和污染物浓度20 min降幅接近(分别为0.5～0.53和50%～55%)接近,而COD和TSS平均浓度与初期浓度的比值和污染物浓度20 min降幅相近(分别为0.35～0.37和78%～84%)。对于校园人行道,污染物浓度20 min降幅均达到90%以上(90%～96%),场次降雨径流的总氮、总磷、氨氮、COD和TSS的平均浓度与初期浓度的比值接近(0.3～0.4)。研究结果为山地城市暴雨径流的污染控制提供了参考。     

北京城区雨水径流水质及其主要影响因素

掌握城区雨水径流水质及其主要的影响因素是有效地利用城区雨水资源和控制城市非点源污染的基础。根据北京 1998— 2 0 0 0年大量的降雨径流水质数据 ,本文分析了城区屋面和道路雨水径流的水质变化规律及其主要影响因素城市雨水径流的水质很差 ,初期径流的污染程度甚至超过城市污水。除了空气质量的影响外 ,最重要的影响因素是屋面材料、道路类型及路面污染状况、气温、降雨强度、降雨量和降雨间隔时间等     

Impact of soil amendments on metribuzin and DCPA half-lives and mobility into agricultural runoff water

The retention and behavior of two herbicides, metribuzin [4-amino-6-tert-butyl-4, 5-dihydro-3-methylthio-1, 2, 4-triazin-5-one] and DCPA [1, 4-Benzenedicarboxylic acid, 2, 3, 5, 6-tetrachloro-, dimethyl] ester, in runoff and seepage water from agricultural fields were investigated. The objectives of this investigation were to: (i) determine the dissipation and half-life (T _1/2) of metribuzin and DCPA herbicides in soil under three management practices: chicken manure (CM), sewage sludge (SS), and no-mulch native soil (NM); (ii) monitor herbicides residues in runoff and infiltration water following addition of soil amendments; and (iii) determine the impact of soil amendments on the transport of NO₃, NH₄, and PO₄ from soil into surface and subsurface water. Half-life (T _1/2) values of metribuzin were 24, 18, and 12 d in CM, SS, and NM treatments, respectively. Similarly, T _1/2 values of DCPA were greater in CM and SS incorporated soil (45.8 and 52.2 d, respectively) compared to NM native soil (26.2 d). Addition of CM and SS to native agricultural soil increased water infiltration, lowering runoff water volume and herbicide residues in runoff following natural rainfall events. We concluded that soil amendments could be used to intercept pesticide-contaminated runoff from agricultural fields. This practice might provide a potential solution to pesticide contamination of surface and seepage water from farmlands.     

On-farm bioremediation of dimethazone and trifluralin residues in runoff water from an agricultural field

Bioremediation is the use of living organisms, primarily microorganisms, to degrade environmental contaminants into less toxic forms. Nine biobeds (ground cavity filled with a mixture of composted organic matter, topsoil, and a surface grass) were established at Kentucky State University research farm (Franklin County, KY) to study the impact of this practice on reducing surface runoff water contamination by residues of dimethazone and trifluralin herbicides arising from an agricultural field. Biobed (biofilter) systems were installed at the bottom of the slope of specially designed runoff plots to examine herbicides retention and degradation before entering streams and rivers. In addition to biobed systems, three soil management practices: municipal sewage sludge (SS), SS mixed with yard waste compost (SS + YW), and no-mulch rototilled bare soil (NM used for comparison purposes) were used to monitor the impact of soil amendments on herbicide residues in soil following natural rainfall events. Organic amendments increased soil organic matter content and herbicide residues retained in soil following rainfall events. Biobeds installed in NM soil reduced dimethazone and trifluralin by 84 and 82%, respectively in runoff water that would have been transported down the land slope of agricultural fields and contaminated natural water resources. Biobeds installed in SS and SS+YW treatments reduced dimethazone by 65 and 46% and trifluralin by 52 and 79%, respectively. These findings indicated that biobeds are effective for treating dimethazone and trifluralin residues in runoff water.     

Persistence and runoff losses of 3 herbicides and chlorpyrifos from a corn field in the Lake Balaton watershed of Hungary

Corn is intensively cultivated in western Hungary in the basin of Lake Balaton, one of the most important water resources in eastern Europe. Pesticide runoff was measured in 1996 and 1997 from a typical corn field near Zalaegerszeg, Hungary, which drains into the Zala River, an important water source of Lake Balaton. Three herbicides, namely atrazine, acetochlor, and propizochlor, and the insecticide chlorpyrifos were applied to bare soil in a field with 5% slope and soil and runoff water pesticide concentrations were monitored. In 1997, a rainfall-runoff simulation experiment was conducted on a small sub-plot in order to measure pesticide runoff under reasonable worst-case conditions. Under natural rainfall almost all losses occurred in a large runoff event in 1996 one month after application in which 3% of atrazine and 1% of acetochlor was transported off the field. Propizochlor and chlorpyrifos losses in the same event were much lower: 0.2% and <0.01%, respectively, because of these chemicals' shorter persistence times in near-surface soil. The rainfall simulation produced only trace amounts of losses even though 4.1 cm was applied in 2 hours; the soil was extremely dry and only 0.2 cm runoff occurred containing less than 0.01% of all chemicals applied. The results suggest that intensive use of corn herbicides, which have been found to result in widespread contamination of water resources elsewhere, may be expected to have the same impact in the Balaton watershed depending on the amounts and intensities used in the basin.     

城市区域不同屋顶降雨径流水质特征

城市屋顶降雨径流是城市面源污染的主要组成部分之一。为了解城市不同屋顶降雨径流的水质特性,以重庆地区5种屋顶为例进行了20场降雨径流的水质监测。研究结果表明,不透水屋顶降雨径流污染物浓度均随降雨历时的延长而降低,混凝土屋顶降雨径流的COD、TP、TN、NH3-N平均浓度分别是瓦屋顶的1.6、1.7、1.4和1.5倍,且不透水屋顶降雨径流总氮的70%~80%为无机氮,总磷的20%~32%为磷酸盐;浅层屋顶降雨径流COD、TN、TP、NH3-N和NO-3-N浓度分别是深层绿色屋顶的0.25~0.26、0.3~0.5、0.07~0.09、0.3~0.6、0.05~0.06倍,且绿色屋顶降雨径流总氮的60%~80%为硝态氮。前期干旱天数和混凝土屋顶径流中的TN、接骨草屋顶径流中的氨氮浓度呈显著正相关关系,混凝土屋顶径流TP浓度与降雨强度显著正相关,降雨持续时间和瓦屋顶径流TSS平均浓度显著正相关。研究结果为城市建筑屋顶降雨径流的科学管理提供了参考。