上海快速城市化进程对多环芳烃湖泊沉积演变的影响研究

发布时间：2018-08-27 05:59

【摘要】：上海近百年来的快速城市化进程,带来人口的急剧增长,同时也带来了一系列的环境污染问题,阻碍了社会、经济与环境的可持续发展。多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)是一种持久性有机污染物,有较强的致癌、致畸、致突变的效应,普遍存在于环境各介质中并且能进行长距离迁移,对环境生态危害极大。本研究将从城市化与环境污染关系的角度出发,通过分析上海城市公园湖泊沉积物中的PAHs,系统探讨了其在不同时间和空间样品中的含量与特征、来源、生态风险,分析城市土地利用/土地覆被变化(LUCC)对表层沉积物PAHs赋存的影响,探究影响多环芳烃沉积的主要城市化参数及其作用机理,为控制城市化过程中的环境污染提供科学建议。表层沉积物样品采自上海市4个城市化区域32个公园湖泊,即核心城区(CUC,位于内环以内)、发达城区(DDU,位于内环和中环之间)、发展中城区(DIU,位于中环和外环之间)和郊区(SU,外环以外)。三沉积柱样品分别采自位于虹口区的鲁迅公园(C1)和杨浦区的复兴岛公园(C2)与新江湾湿地公园(C3)。研究分析得到如下几点认识:上海公园湖泊表层沉积物中16种PAHs总浓度范围是55.75-4928 ng/g,均值为1133ng/g。单因素方差分析结果表明各单体PAHs浓度在城市化区域之间差异较显著(p0.05),呈现出由核心城区向郊区逐渐递减的趋势,高值点主要出现在核心城区交通人口密集区、浦西老工业区和郊区新兴工业区附近。各采样点多环芳烃组分均以4环浓度为最高,各区域之间除2环以外,3环、4环、5环和6环的浓度均值核心城区均大于其他区域,郊区为最低。基于PAHs总浓度的风险评价表明,表层沉积物中TEQ浓度范围为3.42 ng/g-751.2 ng/g,PAHs毒性当量浓度变化情况整体呈现出CUCDDUDIUSU,浓度最高值出现在位于核心城区的鲁迅公园(S1)。基于风险熵(RQ)的风险评估结果表明,单体Flu为高生态风险,核心城区的公园湖泊沉积物PAHs的生态风险最高,发达城区和发展中城区为中等生态风险等级,郊区生态风险水平较低。城市LUCC对表层沉积物中PAHs赋存影响分析中,基于土地利用要素和PAHs浓度数据构建的土地利用回归(LUR)模型揭示了交通拥堵指数和工业点源个数对 PAHs 的显著贡献,以 ∑16PAHs、∑2ringPAHs、∑3ringPAHs、∑4ringPAHs、∑5ringPAHs和∑6ringPAHs浓度为因变量构建的LUR模型调整后的R2分别为0.984、0.529、0.979、0.977、0.974和0.943,三模型交叉检验拟合的PAHs浓度与实测浓度之间均显著相关(p0.01),相关系数分别为0.766、0.679、0.728、0.702、0.715、0.761,RMSE 值分别为 0.362、0.342、0.317、0.447、0.410、0.423。说明构建的模型能较好的模拟了 PAHs浓度的空间分布特征。~(210)Pb和~(137)Cs联合定年法结果表明C1、C2和C3沉积柱分别记录了 1761-2012、1861-2012和1779-2012年间多环芳烃的沉积特征。三沉积柱中∑16PAHs和强致癌∑7PAHs的沉积通量随着时间推进均呈现出波动式增长,尤其是在1949年新中国成立以后和1978年改革开放以后有明显的加速累积过程。经沉积物聚集因子校正后的三沉积柱中∑16PAHs沉积通量和人为沉积通量均值分别为96.03、88.68、220.4 ng/cm2/yr 和 91.80、109.6、280.5 ng/cm2/yr,强致癌∑7PAHs沉积通量和人为沉积通量均值分别为55.82、53.06、125.2 ng/cm2/yr和109.2、65.53、159.5 ng/cm2/yr。2000 年后三沉积柱中∑16PAHs(强致癌∑7PAHs)平均人为沉积通量比值高达 162.74(194.62)、98.82(98.95)、356.78(394.57)。较高的通量比值说明公园湖泊PAHs的历史沉积受到人类活动的强烈影响,C3沉积柱人为沉积通量校准后的数值显著增加可能与其所在的区域的周边环境和本身的地域特征有关。利用正定矩阵因子(PMF)对表层湖泊沉积物进行源解析表明结果PAHs来源主要是交通源和煤及生物质的燃烧,采用特征比值法对沉积柱中的多环芳烃的来源解析,主要来自热解源(主要是化石燃料和生物质的燃烧),其中城市交通源也是主要来源。进一步对城市化参数与多环芳烃沉积的相关性分析发现,上海城市公园多环芳烃湖泊沉积污染格局的形成与演变与城市人口集聚、经济发展水平、能源消耗和产业结构等因素关系紧密。从人口、经济和技术角度构建了扩展的随机影响模型(STIRPAT)并定量解析了城市化参数对多环芳烃沉积的贡献率,结果表明了人口总数、重工业比例和煤炭消耗量是多环芳烃沉积的主要影响因素,这三个指标每提高1%,多环芳烃通量分别增加0.172%-0.198%、0.314%-0.358%和0.297%-0.308%。通径分析结果也表明人口总数、重工业比例和煤炭消耗量对PAHs沉积的直接和间接影响都比较大。
[Abstract]:The rapid urbanization of Shanghai in the past century has brought about a rapid increase in population and a series of environmental pollution problems, hindering the sustainable development of society, economy and environment. Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent organic pollutants with strong carcinogenic, teratogenic and mutagenic effects. In this study, PAHs in lake sediments of urban parks in Shanghai were analyzed from the point of view of the relationship between urbanization and environmental pollution, and their contents, characteristics, sources and ecological risks in different time and space samples were systematically discussed. The effects of land use/land cover change (LUCC) on the occurrence of PAHs in surface sediments were analyzed, and the main urbanization parameters affecting PAHs deposition and their mechanisms were explored. Scientific suggestions were provided for controlling environmental pollution during urbanization. Core urban area (CUC, located within the inner ring), developed urban area (DDU, located between the inner and middle ring), developing urban area (DIU, located between the central and outer ring) and suburban area (SU, outside the outer ring). Three sediment column samples were collected from Luxun Park (C1) in Hongkou District and Fuxing Island Park (C2) and Xinjiangwan Wetland Park (C3) in Yangpu District, respectively. The results showed that the total PAHs concentration ranged from 55.75 ng/g to 4928 ng/g and the mean value was 1133 ng/g in the surface sediments of the lakes in Shanghai Park. The results of one-way ANOVA analysis showed that the PAHs concentration of each monomer was significantly different among the urbanized areas (p0.05), showing a gradual decrease trend from the core urban area to the suburbs, and the high-value points mainly appeared. The concentrations of PAHs in the four rings were the highest in all sampling sites. The mean concentrations of PAHs in the three rings, three rings, four rings, five rings and six rings were higher in the core city than in other areas, and the lowest in the suburbs. The concentration range of TEQ in surface sediments was 3.42 ng/g-751.2 ng/g. The variation of PAHs toxicity equivalent concentration showed CUCDDUDIUSU as a whole. The highest concentration appeared in Luxun Park (S1) located in the core city. Risk assessment based on risk entropy (RQ) showed that flu was a high ecological risk, and PAHs in park lake sediments in the core city was a high ecological risk. In the analysis of the influence of urban LUCC on the occurrence of PAHs in surface sediments, the land use regression (LUR) model based on land use factors and PAHs concentration data reveals that the traffic congestion index and the number of industrial sources affect P The significant contributions of AHs were as follows: the adjusted R2 values of LUR models were 0.984, 0.529, 0.979, 0.977, 0.974 and 0.943, respectively, with 16 PAHs, 2 ringPAHs, 3 ringPAHs, 4 ringPAHs, 5 ringPAHs, and 6 ringPAHs as dependent variables. The values of RMSE were 0.362, 0.342, 0.317, 0.447, 0.410, 0.423, respectively. The results show that the model can well simulate the spatial distribution characteristics of PAHs concentration. ~ (210) Pb and ~ (137) Cs dating results show that C1, C2 and C3 sedimentary columns recorded 1761-2012, 1861-2012 and 1779-2012, respectively. The deposition fluxes of 16PAHs and 7PAHs in the three sediment columns showed a fluctuating increase with time, especially after the founding of New China in 1949 and the reform and opening up in 1978. The 16PAHs deposition fluxes and human activities in the three sediment columns corrected by the sediment accumulation factor. The mean deposition fluxes of 7PAHs and anthropogenic fluxes were 96.03, 88.68, 220.4 ng/cm 2/yr and 91.80, 109.6, 280.5 ng/cm 2/yr, respectively. The mean deposition fluxes of 7PAHs and anthropogenic fluxes were 55.82, 53.06, 125.2 ng/cm 2/yr and 109.2, 65.53, 159.5 ng/cm 2/yr in the three deposition columns after 2000. The high flux ratios indicate that the historical deposition of PAHs in the park lake is strongly influenced by human activities. The significant increase of anthropogenic deposition flux in the C3 sediment column after calibration may be related to the surrounding environment and the regional characteristics of the area in which the PAHs are located. PMF) Source analysis of surface lake sediments shows that PAHs are mainly from traffic sources and combustion of coal and biomass. The source of PAHs in sediment columns is mainly from pyrolysis sources (mainly from combustion of fossil fuels and biomass), and urban traffic sources are also the main sources. The correlation analysis between urbanization parameters and PAH deposition shows that the formation and evolution of PAH lake sediment pollution pattern in Shanghai urban parks are closely related to urban population agglomeration, economic development level, energy consumption and industrial structure. The contribution rate of urbanization parameters to PAHs deposition was analyzed quantitatively. The results showed that population, heavy industry ratio and coal consumption were the main factors affecting PAHs deposition. For each increase of 1%, the flux of PAHs increased by 0.172% - 0.198%, 0.314% - 0.358% and 0.297% - 0.308% respectively. The total number of mouth, heavy industry and coal consumption had direct and indirect effects on PAHs deposition.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X524

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