【作者】 杨波；

【导师】 尹观； 刘峰；

【作者基本信息】 成都理工大学 ， 地球化学， 2004， 硕士

【摘要】 铅同位素由于其质量重，同位素间的相对质量差较小，在地球化学过程中一般不会受所在系统的温度、压力、ph、Eh和生物等作用而发生分馏，外界条件的变化对其同位素组成的影响很小。由以上“指纹特征”的特点，铅同位素被广泛作为指示元素用来示踪环境污染物质的来源。 本文通过对成都市大气铅的主要污染端元物质（汽油、柴油和燃煤）中铅同位素组成的测定和比较，发现了成都市大气铅的两个主要来源（机动车尾气排放和燃煤）之间的铅同位素组成差异规律：成都市机动车尾气铅中的放射成因铅同位素的比重低于燃煤铅中的放射成因成因铅的比重，且成都市机动车尾气铅（汽油、柴油）中²⁰⁷Pb／²⁰⁶Pb值都远远高于燃煤铅中²⁰⁷Pb／²⁰⁶Pb值。并利用这一规律和成都市15个片区的大气浮尘铅同位素组成特征相比较分析研究，结合大气浮尘中其他相关元素的含量特征及当地环境背景，对这些片区的大气铅污染来源及各污染来源的相对贡献大小进行了详细的论证和解释。由此得出了成都市除了热电厂邻近片区以外，大部分地区大气铅污染的主要来源是机动车尾气排放所致。另外还通过大量的实验，探索出一条比较合理的测定大气浮尘及端元物质中铅同位素的实验室工作方法。更多还原

【Abstract】 Lead isotope tracing of major sources of lead pollution in the atmosphere of Chengdu cityThe mass of lead isotope is heavy and the deference of mass number is small. The factors of environment hardly change the composition of lead isotope, for example temperature, stress, Ph, Eh and so on. Based on the geochemical characteristics of lead isotope, the theory base of lead isotope for environmental pollution tracing is analyzed. After measuring and comparing the deference of composition of lead isotope in gasoline, diesel oil and coal, we discover the characteristic that the content of radiogenic lead in gasoline and diesel oil is lower than that in coal and the value of 207Pb/206Pb of gasoline and diesel oil are higher than coal’s in Chengdu, Sichuan. The characteristic of lead isotopic composition is used as a indicator to tracing the source of lead pollution on the atmosphere in Chengdu. We conclude that lead in atmosphere mostly originate from the exhaust of automobile. In addition, we discover a sort of experimental method on measuring the ratio of lead isotope in floating dust by a lot of experiment.更多还原