上海市区与郊区降水的离子组成特征及来源

通过测试上海市区与郊区2008年4月—2009年3月的降水样品中的主要离子浓度值，分析了各离子的浓度变化特征和来源。结果发现：市区总离子浓度值为冬季〉秋季〉春季〉夏季，各离子平均浓度值为SO4^2-〉Ca^2＋〉NH4〉Cl^-〉NO3^-〉Na^＋〉Mg^2＋〉F^＋〉K^＋;郊区总离子浓度值为秋季〉冬季〉春季〉夏季，各离子平均浓度值为SO4^2-〉NH4〉Ca^2＋〉Cl^-〉Na^＋〉NO3^-〉Mg^2＋〉F^-〉K^＋。经定量探源分析，发现降水中离子浓度受人为活动影响严重，市区、郊区降水离子的人为源分别占离子总量的76．8％和71．7％。阴离子中，市区与郊区SO4^2-的人为源所占比例均为最高，cl一的海源大于人为源，且郊区海源比例比市区高10．5％；NO3^-、F^-等均来自人为源。阳离子中，K^＋以陆源为主，市区有部分为人为源；Ca^2＋以人为源为主，且市区人为源比例高于郊区；Mg^2＋以陆源为主，且市区所占比例小于郊区。

Ion Composition and Its Sources of Rainwater from Shanghai Urban and Suburban Areas

Rainwater samples were collected from April 2008 to March 2009 in Shanghai urban and suburban areas. The result showed that total ion concentrations were Winter 〉 Autumn 〉 Spring 〉 Summer in urban areas, and various ion average concentrations were SO4^2- 〉 Ca^2＋ 〉 NH4 〉 Cl^- 〉 NO3- 〉 Na ^＋ 〉 Mg^2＋ 〉 F^- 〉 K^＋. General ion concentrations were Autumn 〉 Winter 〉 Spring 〉 Summer in suburban area, and various ion average concentrations were SO4^2- 〉 NH4 〉 Ca^2＋ 〉 Cl^ - 〉 Na^＋ 〉 NO3^- 〉 Mg^2 ＋〉 F^- 〉 K^＋. Quantitative source analysis showed that rainwater ion composi- tions were mainly affected by anthropogenic activities, anthropogenic source of rainwater ions in urban and suburban areas accounted for the total ion concentrations of 76.8% and 71.7%, separately. In negative ion, anthropogenic source of SO2- in urban and suburban areas was the highest among the total sources. Sea source proportion of Cl^- was bigger than anthropogenic source, and sea source proportion from suburban area was 10.5%, bigger than urban areas. NO3^- and F- were from anthropogenic source. In positive ion, K^＋ was mostly from land source, and part from anthropogenic source in urban areas. Ca^2＋ was mostly from anthropogenic source, and its proportion was bigger in urban areas than that in suburban areas. Mg^2＋ was mostly from land source, and its proportion was bigger in suburban area than that in urban area.