【作者】 张志；

【导师】 李一凡； 任南琪；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2010， 博士

【摘要】 多氯联苯(PCBs)是一类最具有代表性的持久性有机污染物(POPs),对环境和人体健康会产生长期的、潜在的危害。本研究分析了中国PCBs产品的组成,计算其PCBs同系物“指纹”特征;利用被动大气采样器,在全国范围内采集97个大气样品,同步采集184个表层土壤样品,检测了大气和土壤样品的PCBs含量,分析了PCB在中国大气和土壤的空间分布特征和在大气土壤之间的交换特征,建立中国PCBs网格化使用清单,并拟合中国表层土壤PCBs监测数据与PCBs使用量间的回归方程,建立中国表层土壤PCBs网格化残留清单。中国表层土壤样品中共检出73种PCBs同系物,全部采样点Σ73PCBs浓度平均值为1799 pg/g dw,其中城市土壤3352 pg/g dw,农村土壤1354 pg/g dw,背景土壤1345 pg/g dw。土壤中以低氯代PCBs同系物为主,四氯PCBs同族体比例最高,城市土壤中高氯代PCBs组分稍有富集。中国大气样品共检出60种PCBs同系物,Σ60PCBs平均浓度为250 pg/m3,城市350 pg/m3,农村230 pg/m3,背景77 pg/m3,以低氯代PCBs为主,三氯PCBs比例最高。城市大气土壤PCBs水平明显高于农村和背景地区。相同采样点大气和表层土壤中ΣPCBs浓度数据具有极显著地正相关关系,Pearson相关系数R = 0.315,P < 0.01,说明大气和土壤之间进行着频繁的PCBs交换和迁移转化。中国大气和表层土壤中ΣPCBs浓度低于欧洲和北美等地区,高氯代PCBs的比例远低于欧洲和北美地区,本研究充分证明了中国并非欧美等地区PCBs的污染源。中国大气和表层土壤中PCBs组成与中国生产和使用的PCBs特征更接近,说明中国生产和使用的PCBs是中国大气和土壤中PCBs最主要的污染源。主成分分析表明,中国大部分农村地区土壤和大气中PCBs主要来源是中国PCBs产品;而重庆、昆明和包括上海及附近的几个采样点土壤中以及中国某些南部地区的大气PCBs的污染源可能包括进口PCBs产品。在中国范围内发现PCBs的“分馏”效应,大气和土壤中低氯代PCBs同族体的比例由城市到农村再到背景递增,高氯代PCBs同族体比例由城市到农村再到背景地区递减。中国背景/农村表层土壤的ΣPCBs浓度在东经80°-122°范围内与经度发现了较强的相关性,从东到西高氯代PCBs同族体比例降低,而低氯代PCBs同族体比例升高,由此在全世界POPs研究中第一次提出了PCBs的“经度分馏效应”。在上海地区土壤样品中以中国范围内土壤样品中发现并证实了PCBs的“城市分馏效应”。背景/农村地区低氯代PCBs同族体浓度在土壤-大气间有很强的相关性,城市地区高氯代PCBs同族体浓度在大气-土壤间具有很高的相关系数。建立中国精度为1/6o纬度×1/4o经度的PCBs网格化使用清单,清单表明中国PCBs的使用主要集中在中部和东部人口密集的地区。在东经96-130度,北纬20-50度区域内使用量较大。PCBs使用量最大的地区包括:四川、湖南、广东、河南、山东和江苏,PCBs累计使用量为1000-1640吨。北京、天津、上海和重庆等地区使用总量不大,但具有较高的使用密度。中国PCBs网格化使用清单数据与中国大气和土壤中PCBs监测数据都具有很强的相关性,利用该中国表层土壤与PCBs网格化使用清单的线性回归方程,计算出中国表层土壤PCBs残留清单。中国表层土壤PCBs残留量较高的地区主要集中在人口密度大,工业化程度高,经济相对发达的中部和东部,如北京、河北、河南、江苏、上海、四川、重庆和广州等地区。省会或较大的城市人口密集,在清单上表现为具有较高土壤PCBs残留量的点。中国表层土壤PCBs残留清单的建立为我国PCBs的进一步的研究打下了坚实的基础。更多还原

【Abstract】 Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) which can impose a threat to human health and the environment. In this study, congener and homologue profiles of Chinese PCBs production were studied, based on which fingerprint characteristics of Chinese PCBs production were identified; 97 air samples were collected by using passive air samplers and 184 surface soil samples were also concurrently collected; PCBs concentration of the air and soil samples were measured; the spatial distribution of PCB in Chinese air and soil was analyzed; the air-soil exchange of PCBs between Chinese air and soil was investigated; grided Chinese PCBs usage inventories were established; grided Chinese surface soil PCBs residue inventories were established by taking advantage of a significant correlation between PCBs usage and concentration of PCBs in Chinese surface soil.A total of 73 PCBs congeners were detected in Chinese surface soil. Mean concentration ofΣPCBs was 1799 pg/g dw (dry weight), 3352 pg/g dw in urban sites, 1354 pg/g dw in rural sites, and 1345 pg/g dw in background sites. The mainly homologues were lower molecular weight (LMW) PCBs, and 4Cl-PCBs have the highest concentration in soil sample. The higher molecular weight (HMW) PCBs were more enriched in urban soil. 60 PCBs congeners were detected in Chinese air samples. Mean concentration ofΣPCBs was 50 pg/m3 (urban: 350 pg/m3, rural: 230 pg/m3, and background: 77 pg/m3). The mainly homologue is LMW PCBs, and 3Cl-PCBs have the highest concentration in air sample. A highly significant correlation (R = 0.315, P < 0.001) was found inΣPCBs concentration between Chinese air and surface soil samples. The PCBs concentrations in both air and soil at urban sites were higher than those at rural and background sites. It was found that the PCB concentrations in Chinese air and surface soil were in general lower than those in Europe and North America, and there were more HMW PCBs in the air and soil in Europe and North America than those in China.The PCB homologue composition in Chinese air and surface soil was similar to that of the PCBs produced and used in China,which indicates that the PCBs produced and used in China were the major sources of PCBs in Chinese air and surface soil. A further study by using Principal Component Analysis (PCA) was carried out to identify the sources of PABs found in Chinese air and soil. Some sources other than China-produced PCBs were also identified. For example, the sources of PCBs in soil samples in shanghai, chongqing, and kunming and in Southern China air were probably came from imported PCBs products.The fractionation effect was investigated in China, and the phenomenon of the“longitude fractionation effect”was found for the first time in the world POP’s research, showing the decrease of total PCB concentrations and the proportion of MMW PCBs and increase of LMW PCBs from east to west in both Chinese rural/background air and soil. A significant correlation between concentrations of PCB congeners/homologues in Chinese surface soil with longitude in 80°-122°E was found, The“urban fractionation effect”was also confirmed in the soil samples around shanghai and in whole China, characterized by high portions of HMW PCBs in urban area and high portions of LMW PCBs in rural and background area., and a strong soil-air correlation for LMW PCBs in the background and rural sites, whereas a strong soil-air correlation for HMW PCBs in the urban sites.Gridded China PCB usage with a 1/6o latitude by 1/4o longitude resolution was established. The dense usage of Chinese PCBs focused on the eastern part of the country with highly developed industry and large population, and was in the region between 96-130°E longitude and 20-50°N latitude.Based on the gridded Chinese usage inventories and a significant correlation between PCBs usage and concentration of PCBs in Chinese surface soil, grided PCBs residue inventories in Chinese surface soil were established, which paved a way for further PCB studies in China.更多还原