【作者】 邢新丽；

【导师】 祁士华；

【作者基本信息】 中国地质大学 ， 环境工程， 2009， 博士

【摘要】 持久性有机污染物（POPs）是一类具有高毒性、持久性的有机污染物，一旦进入环境中就很难降解。POPs的半挥发性使得他们可以通过气流、水流等途径进行长距离传输甚至到达极地地区。不仅如此，POPs很容易通过食物链在生物体内累积，对人体和其他生物体造成危害。例如对肝脏、肾和内分泌系统造成危害并导致癌症和其他疾病。因此，POPs受到极大关注，是一个重要的全球性的环境问题。由于POPs的物理化学特性，它们可以通过大气长距离人气迁移。因此，源区产生的POPs会通过大气和水等扩散迁移介质在更大范围甚至全球范围内重新分配。近期研究表明，热带和亚热带高浓度POPs可以跨越太平洋到达加拿大、北极等高纬度地区。类似地，和低海拔地区相比，高山地区具有温度低、降水多、冰雪覆盖期长、风速和日照强度较强、大气压较低等特点。这些环境特征会影响有机污染物的环境行为，有利于POPs在山区沉降或储存。另一方面，山区具有较高的生物多样性，是低海拔地区的主要水源地，山区环境污染物会对敏感的水生和陆地生态系统具有潜在危害性。因此，研究山区POPs的污染及污染过程对于保护人类水源地和生物多样性具有重要意义。青藏高原具有重大的生态价值，是我国主要的水源发源地，具有多种珍稀动植物。四川盆地西缘是连接青藏高原和低海拔地区的重要组成部分，是水资源输送的重要通道，同时也是POPs从源区向山区传输的通道。然而，到目前为止，这个地带研究较少。因此，本论文选取青藏高原和四川盆地的连接处—成都经济区作为研究对象，讨论了成都经济区POPs浓度分布特征，典型POPs在盆地—山区界面的土气交换和大气传输的季节和空间特征，以及低海拔地区向高海拔地区的迁移通量，揭示盆地—山区POPs传输特征。第一部分：成都经济区土壤POPs污染及分布特征相对其他环境介质而言，土壤中POPs具有半衰期长，变化范围较小等特点，因此，选取士壤中POPs浓度表征成都经济区的POPs分布及污染水平。采用网格法在成都经济区采集表层土壤样品245件，测试分析土壤中有机氯农药和多环芳烃的含量。分析结果如下：1．成都经济区有机氯农药污染及分布特征（1）有机氯农药含量顺序为：DDT＞HCB＞HCH．研究区中心区如成都、德阳和绵阳的部分地区有机氯农药含量高于周围山区的含量：（2）和我国其他地区相比，成都经济区土壤中HCH含量低于我国北方和东部地区的分析结果，但高于经济不发达地区研究结果，如贵阳。DDT含量高于东南部地区和西南地区的研究结果，低于我国北方地区土壤中研究结果。同世界其他地区相比，有机氯农药总量高于欧洲和南美洲研究结果。（3）α-HCH/γ-HCH和p,p’-DDE/p，p’-DDT研究结果表明成都经济区部分地区仍在使用有机氯农药。2．成都经济区多环芳烃污染及分布特征（1）土壤中16种多环芳烃总的平均含量为3233．92 ng g^-1。高分子量多环芳烃在总多环芳烃含量中占主要成分。在空间上看，经济区中心地带和雅安市附近多环芳烃浓度较高：（2）成都经济区16种多环芳烃总平均含量比我国南方报道结果高出一个数量级，和北方地区含量相当。和世界其他地区相比，研究区含量远高于南极和欧洲高山背景值，也高于欧洲部分地区农田土壤中含量；（3）不同多环芳烃含量比值表明草、森林和煤燃烧产生的多环芳烃是高山地区低分子量多环芳烃的主要来源，机动车尾气和工业汽油等燃料的燃烧排放是经济区中心地带高含量多环芳烃的主要来源。3．环境因素对有机氯农药分布的影响（1）总体上，亚热带和温带地区土壤有机氯农药含量高于寒带地区土壤有机氯农药含量；（2）平原和丘陵地区土壤HCHs和HCB含量高于山区土壤有机氯农药含量，然而DDT却表现为山区含量高于平原和匠陵区含量；（3）耕地、林地和建筑用地土壤HCHs和DDTs含量高于草地土壤中相应含量；（4）总体来说，HCHs和土壤中总有机碳含量成正比，DDTs和HCB与土壤总有机碳含量相关性不大；（5）酸性土壤中有机氯农药含量高于碱性和中性土壤中含量：（6）灌木区土壤中有机氯农药含量高于针叶和阔叶林土壤有机氯农药含量。4．环境因素对多环芳烃分布的影响（1）温带和亚热带地区土壤多环芳烃含量高于低温地区土壤中多环芳烃含量；（2）在平原、匠陵和雅安市附近的山区多环芳烃含量高于其他地区含量：（3）水田、旱地和林地多环芳烃含量高于建筑用地和草地中含量；（4）多环芳烃含量和土壤总有机碳含量成正比，四环多环芳烃与总有机碳的相关性高于其他多环芳烃的相关性；（5）酸性土壤中多环芳烃含量高于碱性和中性土壤中含量；（6）针叶林和灌木林多环芳烃含量高于阔叶林中的含量。第二部分：盆地——山区剖面POPs时空分布特征通过区域研究分析，选取大英—清平这一剖面作为POPs时空分布、土气交换和迁移的典型研究剖面。在该剖面设置了10组土壤和大气沉降监测点，大约每隔三个月进行一次样品采集，监测时间为2007年6月到2008年6月，总共采集了39个土壤样，38组干湿沉降样。分析结果如下：1．剖面POPs含量总体特征有机氯农药含量的总体趋势为：土壤中为DDTs＞HCB＞HCHs；降水中为HCB＞HCHs＞DDTs；大气颗粒物中含量顺序为HCB＞DDTs＞HCH。对于多环芳烃来说，土壤和大气干湿沉降中高分子量多环芳烃含量（4-6环）比低分子量多环芳烃（2-3环）含量高。2．季节分布特征对于土壤来说，冬季和秋季HCH利HCB含量高于春季和夏季含量；而DDT则相反，夏季和春季含量较高。对于降水，秋季和冬季含量高于其他季节含量。大气颗粒物中除夏季γ-HCH含量特别高以外，总体特征为冬季和春季含量高于夏季和秋季。对多环芳烃来说，总体特征为冬季和春季含量高于夏季和秋季含量。但是，夏季降水中多环芳烃含量高于其他季节含量。3．空间分布特征对HCHs来说，土壤中含量随海拔增高而增加；与HCH相反，HCB、DDT和DDE最高含量值位于低海拔地区。干湿沉降样品中，低海拔地区含量高于高海拔地区含量。对多环芳烃来说，土壤中低分子量多环芳烃含量和高程成正比，但是干湿沉降样品和高程相关性不明显。4．POPs干湿沉降量特征p,p’-DDE和p，p’-DDT沉降量低于HCB和HCHs沉降量。低海拔地区沉降量高于高海拔地区沉降量。在季节上，HCB和HCHs春季和夏季沉降量高于其他两个季节沉降量。湿沉降对挥发性较高的HCB和HCH的去除效率高，而干沉降对挥发性较低的物质去除效率高。多环芳烃的沉降量普遍高于有机氯农药沉降量。对于Nap来说湿沉降比干沉降更重要，对高分子量多环芳烃米说则相反，表明湿沉降对挥发性较高的物质去除效率高，而干沉降则对挥发性较低的物质来说更重要。空间上，剖面中部沉降量最大。在季节上来看，总体特征为冬季和春季沉降量大于夏季和秋季沉降量。5．环境因素对盆地—山区剖面POPs分布的影响土壤特性对POPs的影响土壤中高挥发性物质（如HCH和HCB）含量与总有机碳含量成正比。土壤HCH含量与土壤中方解石含量成反比，γ-HCH含量与土壤中伊利石含量成正比。挥发性较低的p，p’-DDE和p，p’-DDT与总有机碳含量相关性不明显，但是与蒙脱石和绿泥石含量成正比。对于多环芳烃来说，多环芳烃含量与土壤矿物成分相关性不明显，和土壤总有机碳含量以及高程成正相关。说明土壤总有机碳是士壤多环芳烃残留的主要因素。气象因素对POPs的影响土壤有机氯农药含量与气象因素相关性不明显。干沉降中γ-HCH含量与降水量、温度和湿度成正比，而HCB、p,p’-DDE和p,p’-DDT则和这些因素为负相关。湿沉降中有机氯农药，特别是HCB、γ-HCH和p,p’-DDE与降水量、温度、湿度以及风速成正相关。干沉降中多环芳烃含量与温度和湿度为负相关。Nap湿沉降和湿度，BghiP湿沉降和风速也均为负相关。第三部分：盆地—山区POPs时空迁移模型监测数据显示山区对POPs具有冷凝效应，由于各种化学物质的物化性质不同、环境和气象条件不同，POPs迁移具有时空变化。本文采用四区间逸度动态模型模拟有机氯农药和多环芳烃的时空分布及迁移。模型设定了有机氯农药在无释放源和多环芳烃具有常量释放速度两种前提下的模拟。灵敏度分析表明：表征土壤特性的参数以及温度对模拟结果影响最大。模拟结果表明：研究区POPs正在由土壤向其他环境介质迁移，而沉积物始终是POPs受体；大气和水体中POPs含量随时间变化较大，并且高挥发性物质含量高于低挥发性物质含量。通过比较模拟值与初始值发现，低挥发性物质比高挥发性物质更难降解和迁移。高温季节POPs去除率高于低温季节去除率。大气迁移通量计算值表明挥发性较高的物质具有更长的传输距离。迁移通量随季节变化，冬季迁移量比其他季节小。在空间上看，盆地地区α-HCH迁移通量小于高山地区，而p,p’-DDE则相反，低海拔的盆地地区迁移通量较大，高山地区迁移量很小，再次印证挥发性越高迁移距离越长。多环芳烃迁移通量空间变异小，但是不同物质间差别很大。总体看，多环芳烃迁移通量大于有机氯农药迁移通量，各种多环芳烃迁移通量顺序为：Phe＞Pyr＞BghiP。上述研究表明，盆地—山区POPs的迁移能力与挥发性相关，挥发性越高，迁移能力越强。更多还原

【Abstract】 Persistent organic pollutants （POPs） are a series of toxic organic pollutants, they have longhalf-lives, and hard to degrade once released to environment. They are semi-volatile, can betransported to remote regions even polar regions by wind or water. Moreover, they are likelyaccumulated in organism by food chain, which will be disadvantageous for the health of humanand organism. They are toxic to liver, kidney, nerve, and incretion, which cause cancer and otherproblems. Hence, there are more concerns on POPs, and the problem of POPs has been a globalenvironmental issue.Due to their physicochemical properties, POPs are subject to long-range atmospherictransport. Therefore, POPs released to the source region could be dispersed rapidly by air andwater, and tend to be redistributed at a bigger or global scale. Recently, many studies haveshowed that atmospheric transport from tropical and subtropical which are high POPs emissionregions across the Pacific Ocean to high latitude regions, such as Canadian and Arctic regions.Similarly, high mountain areas usually have relatively low daytime air temperature andrelatively high precipitation compared with lowlands, and most experience long-lasting snowcover. Wind speed and solar radiation flux are higher than in adjacent low lands, whereasatmospheric pressure is lower in high mountains. Many of these characteristics will influence theenvironmental behavior of organic chemicals, which favor for mountain areas act as a "tank" or"reservoir" for POPs. On the other side, mountains have a high degree of habitat diversity and theyare main water source for low altitude regions. The pollution of mountains will be potential threatsto sensitive aquatic and terrestrial ecosystems. So it is of great importance to study the pollutionlevel and pollution process in mountains. Tibet Plateau is of great ecological signification due to its vast water source and lots of sparse animals and plants. The intergrades of mountains linkedTibet and lower land in Sichuan Basin （the west edge of Sichuan Basin） is the necessary path forwater supply and for pollutants transport to high mountains. However, at present, few studies havebeen focused on this region. Hence, in this thesis, a typical region between Tibet and SichuanBasin-Chengdu Economic Region was chosen. The concentration of POPs in this region, seasonaland spatial air-surface exchange and transport characteristics of selected POPs in basin-mountainregion of west edge of Sichuan Basin and the contribution fluxes of POPs from lower land tohigher altitude region were studied.Part one: The regional soil pollution level and distribution characteristics of POPs inChengdu Economic Region （CER）The half-lives of POPs in soil were longer than in other environmental media, so theconcentrations in soil were used to represent the general distribution and pollution level of POPsin CER. Gridding method was used to collect the surface soil samples. In sum, 245 soil sampleswere collected in April, 2006. The concentrations of OCPs and PAlls in soil were analysed.1. The regional pollution level and distribution characteristics of OCPs in CER（1）The concentration order of OCPs was: DDT> HCB >HCH. The concentrations of OCPs atthe centre of CER, like Chengdu, Deyang and some other places in Mianyang were higher thanplaces at surrounding mountains; （2） For HCHs, the concentrations were less than those in northand east of China, but higher than in less developed region, like Guiyang. The concentrations ofDDTs were more than reports on southeast and southwest of China and less than concentrations innortheast of China. Comparing with different mountains in the world, the level of OCPs washigher than those in mountains in Europe and South America; （3） The ratios ofα-HCH/γ-HCH andp,p’-DDE/p,p’-DDT indicated illegal OCPs was still used in some places of CER.2. The regional pollution level and distribution characteristics and geochemicalsignifications of PAHs in CER（1）The average concentration of total 16 PAHs in soil was 3233.92 ng g^-1. HMW-PAHs weremajor fractions of total PAHs in CER. Higher concentration was showed at the centre of CER andhigh mountains near Ya’an City; （2）The average concentration of total PAHs was one order ofmagnitude higher than that of south China, was equivalent to that in north China. Compared toother regions in the world, the concentration was much higher than those of background regions inAntarctic and European high mountain soils, and higher than in some Europe residential and arablesoils; （3） The ratios of different PAHs indicated grass, wood and coal combustion was the main source of LMW-PAHs in high mountains, traffic and industry petroleum combustion was the mainreason of high level PAHs in the centre of CER.3. The influences of environmental variables on Distribution of OCPs（1） Generally, the concentrations of OCPs in the subtropics and temperate zones were higherthan in frigid zones; （2） The concentrations of HCHs and HCB in plain and hilly land were higherthan in mountain area, while the concentrations of DDTs in mountains were higher; （3） In arableland, forests and artificial land, HCHs and DDTs concentrations were higher than in grasslandareas; （4） For most HCHs, the concentration had high positive relationship with soil TOC;however, for DDTs and HCB there was no such tendency; （5） The concentrations of OCPs in acidsoils were higher than in alkali and neutral soils; （6） The concentrations of OCPs in spinney forestwere higher than in conifer forest and broad-leaved forest.4. The influence of environmental variables on distribution of PAHs（1） The concentrations of PAHs were higher in warm temperate zone and subtropical zonethan in low temperature zone; （2） The concentration in plain, hilly land and Ya’an mountainousregion were higher than in other places; （3） The concentration in paddy fields, dry land andforests were higher than in artificial land and grass; （4） There was positive correlation betweenthe concentration of PAHs and TOC. The correlation was more obvious for 4-rings PAHs thanfor 5-, 6-rings PAHs; （5） The concentration of PAHs in acid soils was higher than in alkali andneutral soils; （6） The concentrations in conifer and spinney forest were higher than inbroad-leaved forest.Part two: The temporal and spatial distribution characteristics of POPs at Basin-MountainTransect （BMT）.After the regional investigation, the typical basin-mountain transect from Daying toQingping was selected for studying the temporal and spatial changes, air-surface exchange andtransport of POPs. 10 pairs of soil and air deposition sites along this transect were deployed. Thesamples were collected nearly every three months. The monitoring time was from Jun, 2007 toJun, 2008. 39 soil samples and 38 couples of wet and dry deposition were analysed. Theconclusions in this part were:1. General concentration characteristicsThe general tendency of concentration of OCPs was: in soil samples, the order was DDTs>HCB>HCHs; in rain waters, the order was HCB>HCHs>DDTs; and in dry particles, the orderwas HCB>DDTs>HCHs. For PAHs, the concentration of total HMW-PAHs （4-6 rings） were higher than those of total LMW-PAHs （2-3 rings）.2. Seasonal characteristicsIn soils, the concentrations of HCH and HCB were higher in winter and autumn than inspring and summer; on the contrary, high level DDTs was showed in summer and spring. Forrainwater samples, the concentrations in autumn and winter were higher than in other seasons.For dry deposition particles, high concentrations were found in winter and spring for most OCPs,and a notable high concentration forγ-HCH in summer. The concentrations of PAHs in winterand spring samples were mostly higher than the sample collected in summer and autumn.However, there was high concentration of PAHs in summer rain water.3. Spatial characteristicsFor HCH, the concentration in soil increased as altitude increasing, while the highestconcentrations of HCB and DDT and DDE were at low altitude site. For wet and dry deposition,the concentrations in low altitude were higher than in high altitude. There were positiverelationships between LMW-PAHs soil concentrations and altitude. However, there was noobvious relationship between wet and dry deposition and altitude.4. The deposition characteristics of POPsThe deposition levels of p.p’-DDE and p,p’- DDT were lower than those of HCB and HCH.The depositions at low altitude were more than those at high altitude region. For HCH and HCB,the depositions in spring and summer were more than in other seasons. Wet deposition was moreeffective than dry deposition for more volatile compounds HCH and HCB, while dry depositionwas important for less volatile chemicals.The depositions of PAHs were more than those of OCPs. Wet deposition was moreimportant for Nap than dry deposition, and dry deposition was important for HMW-PAHs,indicating wet deposition is more important for more volatile compound, while dry deposition ismore important for less volatile compounds. Spatially, highest deposition level was showed atthe middle of this transect. Seasonally, the depositions in winter and spring were higher thanthose in summer and autumn.5. The influence of environmental factors on the distribution of POPs at BMTThe impact of soil properties on POPsHigh volatile compounds like HCH and HCB had obvious relationship with the content ofTOC in soils. For HCH, negative relationship was observed with the percentage of calcite in soil,but positive relationship betweenγ-HCH and illite in soil. For low volatile p,p’-DDE and p,p’- DDT, no evident relationship was found between their concentration in soil and TOC, butpositive correlation of them with montmorillonite and chlorite.For PAHs, there was no strong relationship between PAHs concentrations and soil mineralcomposition. While positive relationships were found between PAHs concentration and TOC,PAHs concentration and altitude. TOC was dominating factor for retaining of PAHs in soil.The impact of meteorological factors on POPsMeteorological parameters did not significantly affect the concentration of OCPs in soil.Dry deposition ofγ-HCH had a positive relationship with precipitation, temperature andhumidity. While dry depositions of HCB, p,p’-DDE and p,p’-DDT had a negative correlationwith those factors. Wet deposition of OCPs had a positive relationship with precipitation,temperature, humidity and wind speed, especially for HCB,γ-HCH and p,p’-DDE.There were obvious negative relationships between dry deposition of PAHs and temperatureand humidity. Negative relationship was also found between wet deposition of Nap and humidity,wet deposition of BghiP and wind speed.Part three: The spatial and temporal characteristics transport model of POPs atBasin-Mountain Transect （BMT）Mountain cold trapping has been proved by monitoring data; however, there were spatialand temporal differences due to complex physicochemical properties, environmental andmeteorological parameters. A four compartments dynamic fugacity model was used to explainthe spatial and temporal characteristics, and no emission and constant emission scenarios wereconsidered for OCPs and PAHs respectively.Sensitivity analyse showed the varying of soil and temperature were the most importantparameters influenced the modeling result. Modeling results indicated that soil was the source ofPOPs in other media. Sediment was a more stable compartment for the store of POPs. Theconcentrations in air and water varied seasonally, with concentration of high volatile compoundswas higher than those of low volatile compounds. The comparison of modeling concentrationand initial concentration showed that high volatility compounds were more difficult to reducecomparing with high volatility compounds. The reduction ratio in high temperature seasons washigher than that in cold winter. The calculated air transport fluxes indicated more volatility willresult longer transport distance. And there was seasonal difference; the fluxes in winter weremuch less than those in other seasons. In spatially, the fluxes ofα-HCH at basin sites were lessthan those at high altitude mountains, while the result of p,p’-DDE was reverse, that high air transport fluxes were found at basin （low altitude）, while the fluxes at high altitude were verylow, indicating more volatility will result longer transport distance. There was no obvious spatialdifference for PAHs. However, great difference was showed between different compounds. Thefluxes of PAHs were higher than those of OCPs. The order of fluxes for PAHs was:Phe>Pyr>BghiP. The difference of PAHs also proved there was strong positive relationshipbetween the transport capability and volatility at BMT.更多还原