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1.
路面雨水径流重金属赋存状态研究   总被引:4,自引:0,他引:4  
在对南京机场高速公路路面径流Cu,Zn,Cd和Pb 4种重金属进行监测的基础上,分析了溶解态和颗粒态重金属随径流变化及污染程度,重点探讨了赋存比例.结果表明:产流时间长的小雨事件中,溶解态浓度在径流初期达到最大,此后逐渐降低,颗粒态重金属浓度波动明显;产流时间较短的中雨事件中,溶解态浓度在降雨前期波动明显,此后逐渐降低趋于平稳,颗粒态浓度随径流冲刷逐渐降低;产流时间短的大雨事件中,溶解态和颗粒态浓度均随径流冲刷稳步降低;重金属总浓度水平较高,Cu,Zn,Pb和Cd 4种重金属范围分别为0.048~0.197,0.24~1.03 mg/L,5.3~120.6和0.54~2.34 μg/L;有4场降雨径流颗粒态Pb的EMC值已超过<地表水环境质量标准>中Ⅲ类标准值50μg/L;Cu的赋存比例fd中值为0.573,同时以溶解态和颗粒态存在,其赋存比例受产流时间影响;Zn,Cd和Pb的fd中值分别为0.179,0.258和0.01,主要存在于颗粒态中.  相似文献   

2.
不同屋面雨水径流中PAHs污染特性对比分析   总被引:2,自引:0,他引:2  
对南京市典型沥青屋面、瓦屋面径流中PAHs含量进行了9场降雨事件的现场取样监测,对比分析了2种不同屋面径流中PAHs的EMC值及其各组分的浓度,并对其初期效应及影响因素进行了分析和探讨.结果表明,沥青屋面径流PAHs污染较严重,其平均浓度为4 261.7 ng/L,而瓦屋面径流PAHs平均浓度仅为351.2 ng/L.沥青屋面、瓦屋面径流中PAHs均以4环组分为主,沥青屋面径流中3环组分占较大含量,而瓦屋面径流中5环和6环PAHs浓度仅次于4环PAHs.大多数降雨事件中总PAHs及各组分均存在较显著的初期效应;前期晴天数对PAHs在屋面的累积影响最大,瓦屋面径流PAHs含量受降雨强度影响较大,而沥青屋面径流PAHs含量受降雨量影响较大.  相似文献   

3.
为评价不同类型屋面径流污染特征,通过2016~2018年雨季期间对北京中心城区某沥青屋面和金属屋面径流进行监测,分析其径流污染特征,并评价初期雨水弃流对径流污染的控制效果。研究结果表明,沥青屋面径流和金属屋面径流中化学需氧量(COD)、总磷(TP)和氨氮(NH+4-N)的事件平均浓度(EMC)均远高于《地表水环境标准》中Ⅴ类水的水质标准,总体略高于同类型屋面径流的相关研究报道;研究监测的6场降雨事件,沥青屋面径流中悬浮固体(SS)、COD、TP和NH+4-N的初期冲刷强度均高于金属屋面,在前期晴天数较高或降雨强度和降雨量较大时更为显著;通过提出的径流厚度和污染物排放率关系曲线方法,可定量评价不同初期弃流量对径流污染控制效果,金属屋面和沥青屋面径流弃流3 mm径流厚度后,可以有效控制(72. 75±20. 96)%和(80. 55±15. 94)%的SS污染负荷,以及(66. 91±21. 68)%和(85. 25±11. 28)%的COD污染负荷,弃流后径流污染控制效果较好;但按照3 mm径流厚度弃流后,仍不能一定保证弃流后径流中SS和COD浓度在国家相关规范要求的初期弃流后雨水径流污染物浓度范围内。  相似文献   

4.
危险废物焚烧飞灰中重金属污染特性   总被引:3,自引:0,他引:3  
以危险废物(70%工业废物 30%医疗废物)焚烧飞灰为研究对象,探讨了飞灰中重金属污染特性及其主要化学形态、浓度分布规律.初步得出以下结论:危险废物焚烧飞灰中主要污染重金属为Cd,Pb,Zn,其数量高于生活垃圾焚烧飞灰数倍,属于危险废物;飞灰中主要重金属以可溶及交换态、残留态、Fe-Mn氧化物结合态为主要化学形态,其中As,Cr, Cu比较稳定,而Cd,Pb,Zn易溶出进入环境;飞灰中Cd,Cu大体上呈易富集在小颗粒的趋势,Pb,Zn集中分布在50~125,125~250μm的两个粒级.  相似文献   

5.
上海中心城区地表灰尘与土壤中重金属累积及污染评价   总被引:9,自引:0,他引:9  
通过对上海中心城区土壤与地表灰尘和降雨径流样品的取样调查,探讨了城市不同土地利用类型中重金属Cu,Zn,Cr,Pb的累积特征及其环境效应.结果显示:地表灰尘、土壤重金属在不同土地利用类型中的富集程度均高于土壤背景值,且存在显著性差异.相比之下,灰尘重金属污染比土壤严重,同一土地利用类型灰尘重金属P值为土壤的3~4倍.土地利用方式对重金属在地表灰尘和土壤中的积累有较明显的影响.地表灰尘重金属在工业、交通、居住用地中的含量普遍偏高,而在绿地中的含量普遍较低;土壤重金属在交通、商业和绿地中浓度较高,而工业用地中浓度较低.不同土地利用方式对地表径流重金属含量的影响不同,与土壤相比,地表灰尘直接影响到降雨径流重金属含量,两者之间耦合关系明显.工业、交通、居住和商业用地地表径流中,重金属EMC值以工业用地最高,其次为交通用地,商业和居住用地较小,但Cr,Pb,Zn的平均EMC值都超过了国家Ⅴ类水的标准,具有潜在的环境危害.  相似文献   

6.
长沙市秋季TSP中重金属形态分布和污染评价   总被引:4,自引:0,他引:4  
对长沙市师大附中、雨花区和火车站3个采样点秋季的大气颗粒物(TSP)浓度以及颗粒物中的重金属元素Cu,Zn,Pb和Cd的浓度和形态分布进行了研究分析,并对重金属元素的生物有效性进行了评价.结果表明,不同区域TSP浓度分布差别较大,其中雨花区最高,师大附中最低;TSP中重金属污染广泛存在,元素Zn,Pb浓度比Cu和Cd浓度要高,其中Zn的平均浓度为2.528μg.m-3,Pb为2.347μg.m-3,Cu为0.187μg.m-3,Cd为0.002μg.m-3.Tessier化学形态分析结果显示:Cu在前四态中含量非常高,特别是可交换态和碳酸盐态.Zn,Pb和Cd在前4态中分布也较多,表明4种金属元素迁移性高.生物有效性评价结果显示TSP中重金属生物可利用性强,Cu和Cd的生物有效性要高于Zn和Pb.  相似文献   

7.
2011年10月从钦州茅尾海采集19个海水样品和16个沉积物样品,利用原子吸收光谱仪和原子荧光分光光度计测定钦州茅尾海表层沉积物中6种重金属元素(Cu、Pb、Zn、Cd、Hg、As)含量,采用单因子指数法和Hakanson生态风险指数法对海水及表层沉积物重金属污染特征及潜在生态风险性进行分析和评价.结果表明:该海域海水中Cu、Pb、Zn、Cd、Hg、As的含量(μg/L)变化范围分别为0.9~4.2、0~12.8、0~59.8、0.03~0.34、0~0.105、0.23~0.82,平均浓度(μg/L)分别为2.2、2.3、17.4、0.13、0.047、0.43,其中,海水中的Pb平均含量超过国家一类海水水质标准,各种重金属单因子污染程度依次为Pb> Hg>Zn>Cu>Cd>As.表层沉积物中的Cu、Pb、Zn、Cd、Hg、As的含量(μg/L)变化范围分别为(2.1~46.5)×10-6、(13.9~34.0)×10-6、(21.4~114.1)×10-6、(0.06~0.40)×10-6、(0.001~0.126)×10-6、(3.77~19.63)×10-6,平均含量(μg/L)分别为18.1×10-6、26.3×10-5、56.7×10-6、0.19×10-6、0.056×10-6、9.60×10-6.该海域重金属综合污染程度和潜在生态风险性均较低,重金属元素污染程度Cu> As>Pb>Cd> Zn> Hg,重金属元素对海洋生态系统潜在危害的影响程度Cd>Hg>As>Cu>Pb>Zn,沉积物中主要潜在生态风险因子为Cd、Hg.  相似文献   

8.
重金属复合污染对小麦生物量的影响   总被引:7,自引:2,他引:7  
针对重金属Cd、Pb、Cu、Zn作为复合体对土壤--植物系统的污染时有发生,实验研究了重金属复合污染对盆栽小麦生物量的影响.结果表明,随着Cd、Pb、Cu、Zn四种重金属元素处理浓度的不断升高,小麦的根、穗、茎和叶等生物量总的趋势为不断降低;由于Cu、Zn两种金属是小麦生长必需的微量元素,所以在Cu、Zn低浓度处理状态下,能够抑制Cd、Pb等复合作用的影响,从而使小麦生物量降低幅度相对减少.  相似文献   

9.
目的研究北方严寒地区路面径流污染的影响因素以及变化特征,为治理径流污染及雨水资源化利用提供基础性资料.方法以沈阳建筑大学校园内的沥青路面为研究对象,进行了实地采样监测,分析沥青路面径流污染物降雨历时的变化规律及污染的影响因素.结果校园区沥青路面的初期径流雨水污染严重,COD_(cr)和NH_3-N质量浓度的最高值分别达到了407.23 mg/L、3.25 mg/L,TSS质量浓度达到886 mg/L.超出地表V类水标准,不宜直接收集利用.结论干沉降期越长,污染物质量浓度也越高;降雨强度小,降雨量少,会导致径流缓慢,污染物质量浓度呈现小幅度上升趋势;持续性降雨冲刷效果较好,污染物质量浓度呈明显下降趋势.南北方径流污染特征的差异主要源于气候,南方气候湿润干沉降小,年降雨量大,冲刷频繁,径流水质较好.  相似文献   

10.
采集青山湖(4号湖)18个样点共计50个沉积物样品,分析了Cu、Pb、Cr、Cd、Ni、Hg、As和Zn等8种重金属的分布特征,并采用内梅罗综合污染指数法、地累积指数法和潜在生态危害指数法进行生态风险评价.结果显示,除Hg和Ni外,其它重金属的平均含量均超出湖北省A层土壤元素背景值以及全国土壤环境质量标准(GB 15618-1995)的限值,以Cd污染最严重,其次依次为Cu、Zn、Pb、As等;且每种重金属空间分布的差异性不大.内梅罗综合污染指数评价显示,青山湖沉积物大部分重金属指标处于V级严重污染状态,污染程度由高至低依次为:Cd Cu Pb Zn As Cr Ni;地累积指数评价表明,沉积物重金属污染程度由高至低依次为:Cd Cu Zn Pb As Cr Ni;潜在生态危害指数评价表明,青山湖所有样点重金属均表现出很强的潜在生态风险,风险由强到弱依次为:Cd Cu Pb As Zn Ni Cr,其中Cd的生态风险贡献率达90.25%.研究表明,青山湖沉积物重金属污染严重,其中Cd为最主要的污染元素,潜在生态风险极高,其次为Cu、Pb、Zn、As.  相似文献   

11.
兴安落叶松林降雨再分配及其穿透雨的空间异质性   总被引:4,自引:0,他引:4  
【目的】探究大兴安岭北部兴安落叶松林对降雨的截留再分配及树冠下穿透雨空间分布规律,了解兴安落叶松林生态水文过程。【方法】通过长期定位观测研究的方法,获取了2013年兴安落叶松林19场降雨事件的林外降雨、穿透雨和树干径流的观测数据,采用相关分析,总结了兴安落叶松林降雨再分配规律,比较了树冠下不同位置处穿透雨的变异性。【结果】观测期内兴安落叶松林的林冠截留量、穿透雨量和树干径流量依次为35.14、148.61和0.250 7 mm,分别占大气降雨量的19.10%、80.77%和0.14%;不同降雨事件中,树冠不同位置处的穿透雨具有空间异质性;当降雨量、温度等气象因子一致时,3/4树冠半径处的穿透雨变异最小,树冠外缘(4/4树冠半径处)变异最大;当冠层结构稳定时,穿透雨的变异程度均随降雨量的增加而减小,二者呈一定的负相关性(P0.01)。【结论】穿透雨是兴安落叶松林降雨再分配的主要水文分量(约占降雨量的81%),选择变异最小、最接近林分穿透雨率(误差约1%)的3/4树冠半径处布设穿透雨收集装置,能够适当减少野外工作量,提高科研观测效率,可为落叶松林区森林水文模型的参数化提供依据。  相似文献   

12.
The asymmetry of rainfall process   总被引:2,自引:0,他引:2  
Using hourly station rain gauge data in the warm season (May-October) during 1961-2006, the climatological features of the evolution of the rainfall process are analyzed by compositing rainfall events centered on the maximum hourly rainfall amount of each event. The results reveal that the rainfall process is asymmetric, which means rainfall events usually reach the maximum in a short period and then experience a relatively longer retreat to the end of the event. The effects of rainfall intensity, duration and peak time, as well as topography, are also considered. It is found that the asymmetry is more obvious in rainfall events with strong intensity and over areas with complex terrain, such as the eastern margin of the Tibetan Plateau, the Hengduan Mountains, and the Yungui Plateau. The asymmetry in short-duration rainfall is more obvious than that in long-duration rainfall, but the regional differences are weaker. The rainfall events that reach the maximum during 14:00-02:00 LST exhibit the strongest asymmetry and those during 08:00-14:00 LST show the weakest asymmetry. The rainfall intensity at the peak time stands out, which means that the rainfall intensity increases and decreases quickly both before and after the peak. These results can improve understanding of the rainfall process and provide metrics for the evaluation of climate models. Moreover, the strong asymmetry of the rainfall process should be highly noted when taking measures to defending against geological hazards, such as collapses, landslides and debris flows throughout southwestern China.  相似文献   

13.
Diurnal variations of summer precipitation in Beijing   总被引:13,自引:1,他引:12  
Climatic characteristics and secular trends of diurnal variations of summer precipitation in Beijing are studied using hourly self-recording rain-gauge data during 1961-2004. The results show that both rainfall amount and rainfall frequency present high values from late afternoon to early morning and reach the minima around noon. Two separate peaks can be identified in the high value period, one in the late afternoon and the other in the early morning. Taking the rainfall duration into account, it is found that the rainfall during late afternoon to midnight mainly comes from the short-duration rainfall events (an event of 1-6 hours in duration), while the rainfall during midnight to early morning is accumulated mostly by the long-duration rainfall events (an event that lasts longer than 6 hours). In the recent 40 years, the summer precipitation in Beijing has been considerably restructured. The total rainfall amount of short-duration events has increased significantly, while the total rainfall amount of Iong-duration events has decreased.  相似文献   

14.
利用四川盆地和重庆地区1980-2012年主汛期(5-9月)基本站小时降水观测资料,分析了短时强降水事件降水量、频次和强度的日变化特征,研究了短时强降水事件日峰值位相和空间分布特征,事件极值降水日变化和持续时间等分布特征,得出以下主要结论:1)川渝盆地短时强降水事件开始时间的日变化上(01:00-24:00时,北京时间,下同),表现为“V”型结构下典型夜间峰值位相特征;结束时间的日变化上,表现为多个峰值型结构分布.强降水事件持续时间的日变化上,频次和降水量均呈双峰型结构,频次极大峰值出现在3 h,而强度上随着持续时间的延长,呈现逐渐增加的趋势;2)短时强降水事件极值开始时间空间分布上,极大频次和极大降水量出现在20:00-01:00时内,主要分布在盆地南部和西部大部分地区;日峰值频次结束时间主要发生在20:00-01:00时和08:00-13:00时两个时段内,主要分布于盆地南部、中部和西部大部分地区;3)短时强降水事件极值降水的日变化上,降水量和频次呈现单峰型结构,白天多为短时间(2~4 h)强降水事件出现极值,而傍晚开始至第二天清晨,持续2~10 h强降水事件出现极值均有发生;强降水事件极值降水持续时间日变化,1~24 h内呈单峰型结构,峰值出现在2 h.  相似文献   

15.
To better understand the key role of biological soil crusts (BSCs) in redistribution processes of limited water resources in semi-arid sandy ecosystems, surface runoff over BSCs in a sandy area in the southern Mu Us sandy area was observed in this study. The results indicated that runoff occurred twice among six rainfall events during the experimental period. Runoff yields varied among types of BSCs, and that they increased in the following order: light algae crusts, dark algae crusts and moss crusts. These findings showed that runoff yields were increasing with the development of BSCs. The percentage of runoff in individual rainfall events increased from light algae crusts to moss crusts, which indicated that the redistribution ratios of different types of BSCs differed. Surface runoff of BSCs may be influenced by rainfall, rain intensity, degree of water saturation of the BSCs before the rain and degree of development of BSCs. Formation of BSCs on the surface of sand dunes changed the spatial distribution pattern of water in this semi-arid sandy ecosystem, which increased the heterogeneity of resources such as water and nutrients. Therefore, making appropriate disturbances of BSCs during storm season is beneficial to maintaining the balance of natural resources in the semi-arid sandy ecosystem.  相似文献   

16.
The 6 major ENSO events since 1979 are classified into the strong and moderate ENSO based on intensity. The composite analysis is performed to reveal the influence of ENSO on East Asian summer monsoon (EASM) and summer rainfall in eastern China. It is shown that the influence is changed with the seasonal cycle in summer, with a weaker influence in June and a stronger influence in August, indicating a long lagged effect of ENSO on EASM. Besides, the circulation and rainfall anomalies caused by the strong ENSO are also stronger with an earlier starting time, while the influence of the moderate ENSO is evident in August. The composite summer rainfall in eastern China for the moderate ENSO exhibits a northern rainfall pattern, which is totally different from the classical ENSO-type rainfall pattern. Based on the composite analysis, two moderate ENSO years with a similar intensity (i.e., 1995 and 2003) are compared. The result shows that, the response of EASM to the moderate ENSO during June and July is, to a certain degree, modulated by the circulation systems in mid-high latitudes of Eurasia and in the Southern Hemisphere, thereby inducing a different rainfall distribution in eastern China. In comparison with the strong ENSO in 1983, it is further revealed that, the strong ENSO plays a dominant role in summer rainfall anomalies in eastern China as well as in controlling the influence of the other factors on EASM. The strong ENSO is therefore different with the moderate ENSO.  相似文献   

17.
以1951—2014年淮河流域29个站点月降水量数据为研究对象,运用线性趋势、累积距平、小波分析及空间分析等方法,分析了降水量时间和空间变化特征.结果表明:(1)1951—2014年,年、春、夏和秋季降水量呈不显著减少趋势,冬季降水量则具有不显著增加趋势.(2)春、秋和冬季易发生旱涝灾害,夏季降水量变化控制年降水量变化.(3)年降水量具有准2a和6a振荡周期.(4)东南部年和四季降水量多于西北部,这与我国年和四季降水量分布模式一致.(5)空间上,年和四季降水量变率中,年和夏季最大,降水量减少区域呈半环状包围降水量增加区域;整个流域冬季降水量几乎没有变化.  相似文献   

18.
Wet and dry deposition of Chernobyl releases   总被引:3,自引:0,他引:3  
M J Clark  F B Smith 《Nature》1988,332(6161):245-249
The passage of the Chernobyl plume over the United Kingdom in May 1986 led to the deposition of radionuclides on the ground by wet and dry deposition processes. Here we analyse rainfall during the passage of the plume and the published monitoring data obtained afterwards, and show that levels of deposited 137Cs can be closely related to rainfall intercepting the plume. 137Cs was present in the atmosphere mostly as particulate species with wet deposition mechanisms dominating. In contrast, 131I was present as particulate and vapour phase material, and reported levels on grass and in cow's milk show that both wet and dry deposition mechanisms were important. 131I on grass and in cow's milk therefore shows a different geographic pattern to 137Cs, and is not so closely related to rainfall. We have calculated washout factors for locations where there are data on deposition, rainfall and air concentrations during the passage of the Chernobyl plume. From these factors and interpolated concentrations in the atmosphere, the total deposition of 137Cs has been estimated at each of 4,000 rain gauge stations in the United Kingdom. The results are presented as deposition contours and have been compared with measurements in parts of the country. Estimates of the total deposition of 131I and 137Cs show that less than or equal to 1% of the estimated total releases from Chernobyl were deposited on the United Kingdom.  相似文献   

19.
ENSO事件对中国东部降水的影响研究   总被引:2,自引:0,他引:2  
ENSO事件是影响全球气候异常的强信号 ,目前人们就ENSO事件对我国气候影响的研究 ,主要集中在夏季旱涝、台风和东北低温上 ,而在其对气候的季节影响方面研究的较少 .本文主要利用 1915年至 1998年我国东部 36个站点的月降水量等数据资料 ,采用X2 检验的统计方法 ,试图在一个更长的时间序列上来研究我国四季降水与EN SO事件的关系 .统计结果表明 :ENSO事件对中国东部降水的影响随季节、地区的不同而出现不同的特点 .夏季和秋季是ENSO事件与中国季节降水相关较显著的季节 ,其中尤以秋季更为显著 ,华北和华中地区是相关较好的地区 .  相似文献   

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