【作者】 赵多勇；

【导师】 魏益民；

【作者基本信息】 中国农业科学院 ， 农产品质量与食物安全， 2012， 博士

【摘要】 重金属污染对农产品安全和人类健康构成了严重威胁。人体重金属暴露途径识别及污染来源分析对控制重金属污染，保障食用农产品安全，减少危害发生具有重要的意义。本研究通过解析陕西某工业区重金属污染来源、迁移途径和人体暴露途径，旨在（1）研究重金属在“环境—农产品—人体”系统中的迁移途径和规律；（2）为重金属在“环境—农产品—人体”系统中污染源解析奠定方法基础；（3）为环境和农产品重金属污染综合防治提供技术支撑。以工业区居民的人体生物标志物（头发和指甲）、食用农产品、土壤、灰尘和大气降尘等介质为实验材料，采用微波消解-电感耦合等离子质谱法，测定铅（Pb）、镉（Cd）、锌（Zn）、铜（Cu）和铬（Cr）等重金属元素含量及铅同位素比率特征值；借鉴美国环境保护局提供的暴露评估模型，分析工业区居民重金属暴露途径，评估居民不同暴露途径的健康风险。根据健康风险大小，确定工业区居民主要暴露途径及危害最大的重金属元素。在确定人体主要暴露途径和危害最大元素的基础上，利用地理信息技术定性识别该元素的主要污染源；结合同位素比率分析技术定量解析各污染源的贡献率，并确定该元素在“环境—人体”系统中迁移途径和规律。主要结论如下：（1）工业区食用农产品、土壤、灰尘和大气等介质均受到不同程度的Pb、Cd、Zn、Cu和Cr污染；人体生物标志物重金属超标证实环境重金属污染对人体造成了危害。（2）工业区居民人体重金属主要来源于膳食和灰尘；小麦籽粒中的铅主要来源于大气降尘；大气降尘中的铅主要来源于金属冶炼活动和工业燃煤。（3）工业区居民Pb、Cd、Zn、Cu和Cr5种重金属经膳食途径和“灰尘—人体”途径总暴露风险均达到不可接受水平。其中，膳食途径暴露风险高于“灰尘—人体”途径；铅暴露风险高于其他重金属。小麦作为调查工业区居民最主要的食用农产品，对人体铅负荷贡献最大。（4）在本研究区域内，在仅考虑“大气或土壤—小麦—人体”途径的情况下，铅主要经“大气—小麦—人体”途径进入人体；经“土壤—小麦—人体”途径进入人体的比例较少。铅经“环境—小麦—人体”迁移途径应引起高度重视。（5）降低工业区人群重金属暴露风险的主要途径为，减少当地产农产品摄入量的同时，应降低人群接触灰尘的频率；控制小麦籽粒铅污染应从大气铅污染控制着手；控制大气铅污染的根本途径为，减少铅锌冶炼排放和燃煤排放。本研究的创新点在于：系统研究了重金属污染物在“环境—农产品—人体”系统中的迁移轨迹，综合运用风险评估技术、3S技术和铅同位素指纹分析技术定性和定量解析了各污染源经“环境—农产品—人体”途径的相对贡献率，有效揭示了“环境—农产品—人体”系统中铅污染的来源。更多还原

【Abstract】 The heavy metal pollution in environment has posed great threat to agro-food products safety andhuman health. In order to control heavy metal pollution, guarantee agro-food products safety and reducethe hazard probability of human health, source identification/apportionment and transfer route ofheavy metal is of great significance. With a case study in an industrial area in Shaanxi Province, China,the heavy metal pollution source, as well as transfer route and the exposure pathway of local residents inenvironment-agro-food-human body system were identified and apportioned. Based on this research,the thesis tries:(1) to explore the law of transfer route of heavy metal inenvironment-agro-food-human body system;(2) to pave the way for heavy metal pollution sourceidentifying and apportioning of the environment-agro-food-human body system; and (3) to providetechnology support for controlling heavy metal pollution in the environment and agro-foods.Biomarker, agro-food products, soil, house dust and atmospheric deposit samples were collected inthe industrial area in northwestern China to analyze heavy metal (Pb, Cd, Zn, Cu and Cr) concentrationsand lead isotope compositions by microwave digest-inductively coupled plasma mass spectrometry(ICP-MS) method. Health risk of local residents in different exposure pathway in object area wasassessed under the guide of exposure model of United States of Environment Protection Agency(USEPA). Based on the result of health risk, the main exposure pathway and most hazardous element oflocal residents were identified. Then, the contribution rate of main pollution source to human body, aswell as transfer route of the most hazardous element, were identified and apportioned by GeographicInformation System (GIS) and lead isotope fingerprint technique. Finally, the transfer route of heavymetal in the environment-human body system was identified.The main conclusions were as follows:(1) Agro-food products, soil, house dust, and atmospheric deposits were all polluted by Pb, Cd, Zn,Cu and Cr in different levels. The exceeding rate of heavy metal in biomarkers (especially scalp hairand finger nail) of local residents proved that heavy metal pollution had brought adverse effects onhuman health.(2) Heavy metal in human body from the industrial area was mainly from agro-food products andhouse dust. Pb in wheat kernel was mainly from atmospheric deposit. Pb in atmospheric deposit wasmainly from Pb-Zn smelting and coal combustion in the local area.(3) The total health risk of local resident exposure to Pb, Cd, Zn, Cu, Cr through dietary pathwayand house dust-human body pathway were beyond the accepted level. Between the two pathways,health risk through dietary one was higher than that of house dust-human body pathway in terms ofTarget Hazard Quotient (THQ). THQ of Pb was higher than that of Cd, Zn, Cu, and Cr. Wheat, as astaple food of local residents, was also the main Pb contributor to human body.(4) Considering dietary pathway exclusively, the main transfer route of Pb from environment tohuman body was atmospheric deposit-wheat-human body route in the environment-agro-food products-human body system. The soil-wheat-human body route was secondary route. Therefore,the transfer of Pb through environment-wheat-human body route should be paid great attention.(5) The effective way to reduce health risk of local residents was to cut down the intake ofagro-food produced local area, as well as reduce the touching frequency of house dust. The effectiveway to control Pb pollution in wheat kernel should start with controlling Pb pollution of atmosphericaerosol. The effective way to control atmospheric aerosol pollution was to reduce the emission of Pb-Znsmelting and coal combustion.Innovative point of this research: The transfer trajectory of heavy metal in theenvironment-agro-food-human body system had been studied systematically. Based on riskassessment,3S and lead isotope fingerprint technique, the contribution rate of Pb pollution source tomedia in environment-wheat-human body system were identified and apportioned. Then the transferroute and law of Pb in the environment-wheat-human body system were effectively explained.更多还原