贵阳大气降水硫同位素地球化学特征  

Sulfur isotopic geochemical characteristics in precipitation at Guiyang

作　　者：肖红伟[1] 肖化云[2] 龙爱民[1] 王燕丽[2] 

机构地区：[1]中国科学院南海海洋研究所热带海洋环境国家重点实验室,广东广州510301 [2]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002

出　　处：《地球化学》2011年第6期559-565,共7页Geochimica

基　　金：国家自然科学基金(40573006;40721002;40373039)

摘　　要：对贵阳地区2008年10月1日至2009年9月30日降水样品的SO 42含量和δ34S值进行了测定。结果表明,研究时段内降水SO 24浓度为13.2 mg/L,δ34S值的变化范围为–12.0‰^+9.4‰,年均值为–2.8‰±1.4‰,主要来源于燃煤释放的含硫物质。大气降水SO 42浓度和δ34S值存在明显的季节性变化特征:冬季高,夏季低。SO 24浓度的季节性变化主要受降水量、污染来源的影响。δ34S值的季节性变化,其主控制因素可能是同位素平衡分馏的温度效应,但还可能受水汽气团来源、生物活动和降水量等多方面的影响。贵阳燃煤释放SO2的δ34S值比其他来源偏负,由于能源结构的调整和技术的改进,燃煤释放SO2量逐年下降,大气降水中δ34S值逐年升高。This study analyzed the concentrations of SO4^2- and values of δ^34S in precipitation taken at Guiyang throughout one year from October 1, 2008 to September 30, 2009. The results indicated that the volume-weighted average concentration of SO2 in one year was 13.2 mg/L, and value of δ^34S was 2.8‰± 1.4‰ within range of 12.0‰ and ±9.4‰. Significant seasonal variations in SO4^2- concentration and δ^34S value, which are high in winter and low in summer, showed that SO4^2- concentration was affected by precipitation amount and pollutant sources, while δ^34S value was mainly affected by isotopic fractionation of equilibrium reaction, and may also by others such as coal combustion, air mass, biological activity, precipitation amount, and the oxidation of atmospheric sulfur. Because the δ^34S value of SO2 from coal combustion is more negative than other sources and the amount of SO2 declined each year, the δ^34S value in precipitation increased each year.

关 键 词：降水 硫同位素组成 来源 季节变化 分馏 贵阳 

分 类 号：P597[天文地球—地球化学] P402[天文地球—地质学]