【作者】 李彭辉；

【导师】 白志鹏；

【作者基本信息】 南开大学 ， 环境科学， 2013， 博士

【摘要】 PAHs因为其致癌、致癌、致突变的三致特性,一直环境学、毒理学等学科是研究的热点,附着在PM2.5上的PAHs组分可以随颗粒物沉积到人体肺泡深处,对人体有显著的健康影响。本论文对老年人这一特殊敏感群体的颗粒物PAHs暴露特征进行研究,分析PM2.5载带的PAHs与人体代谢生物标志物8-OHdG和OH-PAHs的关联,判别老年人的潜在暴露风险与污染物来源。研究在天津两个社区选取101名老人,分别于2011年6月13日-2011年7月2日,2011年11月30日-2011年12月12日两个时间段采集老年人个体暴露、室内环境和区域环境的PM2.5样品,分析其中PAHs组分。在颗粒物样品采样结束的当天,采集老年人的晨尿样品进行分析,反映经监测期PAHs暴露后受试者体内生物标志代谢物的浓度水平。研究结果显示,(1)监测期间区域环境的PM2.5污染严重,夏季PM2.5的平均浓度为98.6μg/m3(浓度范围为28.2-144.8μg/m3),冬季PM2.5的平均浓度为140.Oμg/m3(浓度范围为23.5-325.61μg/m3),均超过了我国《环境空气质量标准》中规定的二级标准。夏季PM2.5载带的PAHs浓度为16.56ng/m3, BbF,InP和BP为主要污染组分；冬季PAHs的浓度为139.82ng/m3, BbF, FluA和Chr为主要污染组分。通过特征PAH组分比值法和因子分析法的分析,得出天津大气中PAHs受包括汽车排放源、煤炭燃烧源和工业排放源等多种源影响。(2)夏季老年人个体暴露和室内PM2.5浓度分别为124.2和120.0μg/m3,冬季老年人个体暴露和室内PM2.5浓度分别为170.8和164.9μg/m3,夏、冬两季老年人个体暴露的PAHs平均浓度分别为22.24和92.12ng/m3,两季的室内PAHs平均浓度分别为21.46和88.06ng/m3。在夏季,PAHs中2环-3环的组分为主要污染物,占总浓度的46%以上；而在冬季,4-6环的大分子组分为主要污染物,占PAHs总浓度的80%以上。个体暴露样品中PAHs各组分浓度和室内样品中PAHs浓度显著相关,和区域环境样品的分析值没有很好的相关性。应用蒙特卡洛模型,结合毒性等价因子等参数对老年人增加的终身致癌风险进行评价,设置了低暴露和高暴露两个情景。在低暴露浓度情景下,老年人中50%人群增加的患癌症风险为5.4×10-7,10%高风险人群增加的患癌症几率为1.48×10-6。而在高暴露浓度情景下,老年人中50%人群增加的患癌症风险为4.29×10-6,10%高风险人群增加的患癌症几率为1.31×10-5。根据EPA对风险范围的描述,天津老年人存在潜在的健康风险。通过特征组分比值法和因子分析法的分析,结果显示在夏、冬两季老年人的PAHs暴露来源由汽车排放源、燃煤源、香烟烟雾等多种源组成。(3)在夏、冬两季季尿液中羟基PAHs分别有7和10种组分有很好的检出。具有挥发性和半挥发性2-3环组分(包括萘和菲)的羟基代谢产物的内暴露水平较高,作为大气暴露风险监测的标志物萘的代谢物,1-OHNaP和2-OHNaP,检出量占所有羟基PAHs检出物的46%以上,大部分检出组分均体现出很好的相关性。对应用最为广泛的1-OHP,天津老年人尿中1-OHP的浓度水平在夏、冬两季有显著的差异,夏天的浓度水平在国内报道值中处于较低的水平；而冬天的浓度超过了一些国家的职业暴露的检出浓度,说明天津老人的处于较高浓度的PAHs暴露环境中,存在着潜在的暴露风险。应用ELISA试剂盒对老年人冬季尿中8-OHdG进行检测,得出尿中8-OHdG的平均浓度为9.08μmol/molcr。与文献报道值相比较,冬季老年人尿中8-OHdG浓度高于健康成人和小学生的检出值,甚至高出了一些工人的职业暴露检出值,表明老年人体内较强的氧化应激反应和潜在健康风险。4)将OH-PAHs、8-OHdG的检出结果与颗粒物中PAHs进行相关性分析,结果显示1-ONaP、2-OHNaP和∑OHNaP均与PM2.5中的NaP具有很好的相关性,指示出PM2.5中NaP对于老年人群体NaP内暴露水平的贡献。而其他羟基PAHs组分和8-OHdG与PM2.5个体暴露样品中PAHs组分没有体现出很好的相关性,但8-OHdG和羟基PAHs各组分间具有很好的相关性。说明相比与呼吸途径暴露,饮食等其他途径的暴露可能对老年人的健康有更强烈的影响。更多还原

【Abstract】 Due to their well-known carcinogenic and mutagenic properties in humans, PAHs are a concern to more and more people and have been widely studied in various environmental and biologic compartments. PM2.5-bound PAHs can deposit deeply in the bronchioles and alveoli of the lungs, and are harmful to human health. Elderly are often at increased risk due to the physical conditions. In this research, PAHs exposure character of elderly was analyzed, and the health risk, PAHs potential soures were estimated. A total of101elderly participants living in two residential communities in Tianjin were recruited for the exposure study from June13to July2, and from November30to December12,2011. Personal exposure, indoor and region PM2.5samples were simultaneously monitored. And the first morning urine samples of elderly were collected after PM sample collecting, to analyze OH-PAHs and8-OHdG.The major results of the study included:1)The average concentration of PM2.5in region samples was98.6μg/m3(ranged from28.2to144.8μg/m3) in summer,140.0μg/m3(ranged from23.5to325.6μg/m3) in winter. China Environmental Protection Agency has recently established the PM2.5National Ambient Air Quality Class2Standard at35μg/m3for the annual standard and at75μg/m3for the24h standard. The PM2.5mass concentration in two seasons both exceeded the24h standard. The PM2.5bound-PAH concentration was16.56ng/m3in summer, BbF, InP and BP were the most abundant compounds. PAHs concentration was139.82ng/m3in winter, BbF, FluA and Chr were the most abundant compounds. Diagnostic ratio analysis and factor analysis indicated the major sources were vehicle emissions, coal combustion and industry emissions.2)In sumer, PM2.5concentration was122.0μg/m3for personal exposure sample,128.6μg/m3for indoor sample. And the concentration was164.8and169.2μg/m3，respectively for personal exposure and indoor samples in winter. The average PAHs concentrations of personal exposure samples in summer and winter were22.24and92.12ng/m3, respectively, and the PAHs concentrations of indoor samples were21.46and88.06ng/m3, respectively. In summer, low molecular weight PAHs (2-3rings) were the major compounds, accounting for over46%of the total PAHs, while in winter, higher molecular weight (4-6rings) were most abundant compounds, accounting for over80%of the total. PAHs in personal expouse samples were highly correlated with PAHs of indoor samples. A probabilistic risk assessment framework was integrated with the toxic equivalence factors (TEFs) and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for the elderly. In low exposure scenario, the median value of inhalation risk was estimated to be5.4×10-7. For10%of the high-risk population, the PAHs induced cancer rate was1.48×10-6. In the high exposure scenario, the median value of inhalation risk was estimated to be4.29×10-7, and for10%of the high-risk population, the PAHs induced cancer rate was1.31×10-5. The risk level higher than the acceptable level of10-6, posed an unacceptable potential cancer risk. Diagnostic ratio analysis and factor analysis indicated multiple sources contributed to the elder PAHs exposure, including vehicle emissions, coal combustion and industry and cigarette smoke.(3) In summer,7OH-PAH analytes were well detected, and in winter10OH-PAH analytes were well analyzed. Low molecular weight PAHs hydroxyl metabolites were the the most abundant compounds.The concentrations of1-and2-OH-Naphthalene were much higher than other analytes, accounting for over46%of the total. Good significant correlation was observed between PAHs hydroxyl metabolites.1-OHP was the most commonly used indicator in biomonitoring studies, the concentration exhibited significant difference between summer and winter. The average concentration of1-OHP in summer samples was lower than the reported dates in China, while in winter, the1-OHP concentration was even higher than the occupational exposure results, indicating potential health risk. The concentration of8-OHdG in morning urine samples was9.08μmol/molcr in winter, higher than the reported dates of healty adults, schoolchild and even some occupational exposure workers, suggesting potential health risk exsit for elderly.4) Good correlations were found between1-OHNaP,2-OHNaP,∑OHNaP and PM2.5-bound NaP, suggesting the PM2.5contribution to elderly exposure. However, no other significant corralations were observed between other urine metabolites and PM2.5-bound PAHs, indicating that ingestion could be the more exposure route for the general population.更多还原