【作者】 蒋煜峰；

【导师】 傅家谟； 王家彤；

【作者基本信息】 上海大学 ， 环境工程， 2009， 博士

【摘要】 由于人口增长和工业迅猛发展,固体废物堆放倾倒、有害废水向土壤中渗透和污水灌溉、大气干/湿沉降等使土壤持久性有机污染物(POPs)污染日益严重。一些POPs具有突出的“三致”作用(致癌、致突变、致畸形)和内分泌干扰特性,日益受到人们的关注。土壤中的POPs可通过挥发、扩散、迁移,污染大气、地表水体和地下水,并可通过生物富集和生物放大作用在生物体内富集,最终危及人体健康。因此,土壤中POPs污染是一个亟需研究和解决的问题。本研究利用气相色谱-质谱(GC/MS)和气相色谱(GC/ECD)方法,对91个上海城区和农村表层土壤样品中的典型POPs包括PAHs,OCPs,PBDEs和PCBs的污染水平、空间分布特征、异构体组成特征、可能的污染来源和潜在的生态风险进行了系统的研究,旨在了解上海地区土壤中典型POPs的污染状况和潜在风险,为我国履行POPs公约提供科学依据。主要研究结果如下:(1)上海市城区土壤中22种多环芳烃(PAHs)的污染浓度在442~19700μg·kg-1之间,平均含量3780μg·kg-1;农村及郊区土壤中22种PAHs的浓度在141~2370μg·kg-1之间,平均浓度为757μg·kg-1。上海市城区土壤中PAHs的总量显著高于农村及郊区土壤。城区不同功能区土壤中的含量由高到低的次序为:路边样>绿化带>公园>商业区>居民区。农村及郊区土壤PAHs污染较高的区域主要在上海西部和南部区域,低污染浓度分布在崇明岛。无论是上海城区土壤还是农村及郊区土壤,污染主要以高分子量的致癌性PAHs为主,其中以Flu,Pyr,BbF和Chr为主要污染物。主成分分析和异构体比值法分析结果表明,上海市土壤中PAHs主要来源于燃烧源,尤其是化石燃料的燃烧。采用毒性当量评价方法对研究区域土壤中PAHs潜在致癌性分析显示,研究区域内城区土壤PAHs具有一定的潜在致癌性,特别是路边土壤样品中毒性当量浓度(TEQ)较高,应当引起重视。而农村土壤中PAHs潜在致癌性较低。(2)上海市土壤样品中六氯苯(HCB)、六六六(HCHs)和滴滴涕(DDTs)的检出率较高,为上海市土壤中主要有机氯农药(OCPs)污染物。上海市城区土壤中OCPs残留范围在3.28~94.7μg·kg-1之间,农村及郊区土壤样品中OCPs农药残留范围在3.16μg?kg-1~265μg?kg-1之间。无论是城区还是农村及郊区土壤,其OCPs残留都以p,p′-DDE为主,占OCPs残留总量的60%以上。从整个分布来看,农村及郊区OCPs污染高的区域主要分布在南部和西部区域;城区不同功能区土壤中,公园和绿化带可能存在历史使用污染,导致其残留高于其它功能区。根据OCPs残留组成推断,试区土壤残留的OCPs主要来源于历史应用,DDT主要是工业DDT和三氯杀螨醇的混合源;HCH则大部分来源于工业HCH,但部分采样点可能来源于林丹污染;氯丹及硫丹部分采样点可能存在近期污染。与我国土壤环境质量标准(GB15618-1995)和荷兰及加拿大土壤环境质量标准以及其它地区OCPs污染残留量比较,上海市土壤HCH残留水平较低。尽管DDT残留量低于其它研究区域,但部分采样点残留量高于国家一级标准。同时生态风险分析显示,DDT残留存在一定的生态风险,因此对研究区域内土壤中DDTs污染应当引起重视。(3)上海市城区土壤中检出的28种多溴二苯醚(PBDEs) (不包括BDE209)的浓度在22.3 ~889 ng·kg-1之间,平均含量258 ng·kg-1;BDE209浓度在0.291 ~ 2910 ng·kg-1之间,平均为477 ng·kg-1。农村及郊区土壤中检出的31种PBDEs (不包括BDE209)的浓度为41.7 ~ 962 ng·kg-1,平均为175 ng·kg-1;BDE209的浓度为33.2~796 ng·kg-1,平均浓度为254 ng·kg-1。农村及郊区土壤中低溴代PBDEs检出率和污染水平要高于城区土壤中低溴代PBDEs,而总量来看,无论是PBDEs总量还是BDE209,农村及郊区土壤中污染水平要低于城区土壤样品。城区污染浓度较高的点主要是P2、G11、G7、L11和C8。低污染浓度样品主要分布在居民区和马路边样。在农村及郊区土壤中较高浓度PBDEs主要是分布在金山区、闵行区、奉贤区和宝山区,崇明岛的污染水平较低。上海市土壤污染物主要以高溴代PBDEs为主,而少部分样品则以四到六溴代为主。相关性分析显示,土壤中PBDEs与TOC具有显著相关性,表明TOC是影响上海市土壤中PBDEs持留的重要因素之一。PBDEs组成特征和统计分析表明,上海市土壤中PBDEs主要来源于十溴和五溴工业品。同时,部分采样点可能存在八溴工业品来源的污染。本研究结果与同类研究结果比较分析显示,研究区域内PBDEs污染高于背景土壤,但显著低于其它有直接污染源的区域,对于当前PBDEs污染应当引起重视,需要进一步监测与研究。(4)上海市城区土壤中共检出74种PCBs同类物,城区土壤中PCBs的污染浓度在232~11300 ng·kg-1之间,平均含量3060 ng·kg-1。城区土壤污染浓度较高采样点主要是C4、C5、G6、G8、G9、L5、R1和R4,污染程度较高的区域主要是商业区和绿化带,低浓度样品主要分布在居民区和马路边样。农村及郊区土壤中共检出62种PCBs同类物,PCBs的污染浓度为71.7~2530 ng·kg-1,平均含量为534 ng·kg-1。农村及郊区污染浓度较高采样点主要是BS2、SJ6、JS4和FX4,从采样区域来看,整体污染水平较低,其污染可能主要来源于城区污染导致的区域大气沉降或是全球大气传输所致。城区土壤大部分采样点污染主要以四氯代、五氯代和六氯代同族体为主,而少部分则以三氯代和四氯代同族体为主;农村及郊区土壤污染主要三氯代和四氯代同族体为主,表明城区和农村PCBs来源不同。土壤中PCBs组成特征及统计分析显示,城区PCBs主要源于Aroclor1242和1254工业品,而农村主要来源于Aroclor1242工业品。相关性分析显示,土壤中PCBs与TOC具有明显相关性,表明TOC是影响上海市土壤中PCBs持留的重要因素之一。本研究结果与同类研究结果比较分析显示,研究区域内PCBs污染高于国内外背景土壤中PCBs水平,但显著低于其它有直接污染源的区域。更多还原

【Abstract】 With the growth of population, rapid development of industry, the soil contamination by persistent organic pollutants (POPs) has become more and more serious by leachate from waste solids, dry and wet deposition, and sewage irrigation. Due to their carcinogenicity, mutagenicity and teratogenicity, as well as endocrine disruptive activity, POPs contamination has increasingly aroused general concern. POPs in soil may contaminate the air, surface water and underground water by volatilization, diffusion and transfer. They easily accumulate in organism by bioconcentration and biomagnification, and finally endanger the health of human beings. So soil contamination by POPs is a key problem to be urgently solved and investigated. The contamination levels, spatial distribution, isomeric composition, possible sources and potential ecological risk of POPs including PAHs, OCPs, PBDEs and PCBs from soil in Shanghai urban areas and agricultural fields were systematically investigated. The study aimed to understanding the soil contamination status and potential risk posed by typical POPs in Shanghai region,and to providing the scientific basis for implementing the POPs convention. The main conclusions are summarized as follows:1. The results showed that the total concentrations of 22 PAHs (ΣPAHs) ranged from 442 to 19700μg kg-1 in urban soil and from 141 to 2370μg kg-1 in agricultural soil of Shanghai, with means of 3780μg kg-1 and 757μg kg-1, respectively. The seven possible carcinogenic PAHs (Σ7CarPAHs) accounted for higher percentage ofΣPAHs. Among different sampling areas, the higher levels of PAHs were found in the roadside, followed by greenbelt, commercial district, park, residential district, and the low concentrations of PAHs were found in agricultural soil. The composition of PAHs was characterized by the high molecular weight PAHs, among which Flu, Pyr, BbF and Chr were most dominant components. The good correlations among the individual PAHs were observed. The contents of individual PAHs were not correlated with soil total organic carbon (TOC) in urban soil; on the contrary, there were significant correlations between soil TOC and individual PAHs in agricultural soil. The principal component analysis (PCA) and PAHs isomeric ratios indicated that PAHs in soil from Shanghai originated mainly from combustion. The risk assessment suggested that soil PAHs carcinogenic potential merited attention at present contamination level in urban areas.2. The total concentrations of 24 OCPs ranged from 3.28 to 94.7μg kg-1 in urban soil and from 3.16 to 265μg kg-1 in agricultural soil of Shanghai, respectively. Among different sampling areas, the higher levels of PAHs were found in the greenbelt and park in urban soil, while the higher contaminated areas were distributed in south regions of Shanghai agricultural field (including Fengxian, Nanhui and Jinshan districts). According to the measured concentrations and detection frequencies, HCHs, DDTs, HCB and heptachlor epoxide were the most dominant compounds among the OCPs. The different compositions of DDTs, HCHs, Chlordane and endosulfan indicated that the residues of these compounds in most soil samples originated from historical application, besides slight recent introduction at some sampling locations. The correlation analysis showed there were no significant relations between TOC and OCPs. The soil quality of Shanghai was classified as low pollution by OCPs. The risk assessment showed that HCH residues in soil did not pose much risk to the geobiont therein, while DDTs posed some risk to the birds and geobiont.3. The concentrations ofΣPBDEs ranged from 22.3 to 889 ng kg-1 in urban soils and 41.7 to 962 ng kg-1 in agricultural soil, and BDE 209 varied from 0.291 to 2910 and from 33.2 to 796 ng kg-1, respectively. BDE 209 was the predominant congener detected among the 44 congeners detected in soil, consisting with the fact that technical deca-BDE mixture is the dominant technical PBDE mixture used in China. Meanwhile, PBDEs homologues analysis and PCA revealed that the major source of PBDEs in Shanghai might be associated with the prevalent use of deca-BDE as a flame retardant, in addition penta-BDE also had contribution on PBDEs contamination in one-third soil samples. Furthermore, high level of PBDEs contamination was observed in north Shanghai because of the rapid development of urbanization and industrialization in the area, while high PBDEs content in urban area were distributed in greenbelts and commercial districts because of point-sources contamination. The correlation analysis showed there were significant relations between TOC and individual PBDEs, suggesting important influence of soil TOC on PBDEs contamination.4. For PCBs contamination, 74 PCB congeners in urban areas and 62 PCB congeners in agricultural fields were identified, and the concentrations ofΣPCBs ranged from 232 to 11300 ng·kg-1 in urban soil and 71.7 to 2530 ng·kg-1 in agricultural soil, with means of 3060 ng·kg-1 and 534 ng·kg-1, respectively. For the urban sites, the higher PCB concentrations in the soil samples were found in commercial and greenbelt area, followed by park, residential and roadside sites, but the differences are not significant. The high level of PCBs were detected in BS2, SJ6, JS4 and FX4 in agricultural fields. The relative content of low weight molecular PCBs were higher in the rural sites than those in urban sites in Shanghai. PCBs homologues analysis and PCA revealed that PCBs in Shanghai might originate from Aroclor1242 and 1254 in urban areas, and Aroclor1242 in agricultural fields. The correlation analysis showed that there was relatively good correlation among the individual PCBs and soil TOC, suggesting important influence of soil TOC on PCBs contamination. Compared with related reports, the level of PCBs contamination was low in the studied areas.更多还原