摘要
本研究于2012年3月-2013年2月,采集了贵州省典型酸雨城市—都匀市的大气降水,分析了其中pH、阴阳离子及重金属元素等分布特征及可能来源。研究结果表明：都匀市降水存在一定酸化现象,40.4%降水样品pH〈5.6。阴离子以SO4^2-和NO3^-为主,平均含量分别为180.7μmol/L、50.7μmol/L,SO4^2-/NO3^-值为1.44-15.62,降水属于硫酸-硝酸混合型。阳离子以NH4＋是最主要的,平均值为129.8μmol/L,占无机阳离子总量的50.8%。降水中重金属元素（Cu、Zn、As、Cd、Pb、Cr）含量较低,与国内其他地区相比,Hg的含量偏高。降水中总离子浓度表现为冬、春季较高,夏、秋季较低。相关性分析表明：降水中化学组分以CaSO4、MgSO4、NH4SO4、Ca（NO3）2等为主。Ca^2＋与Mg^2＋主要来自陆源性颗粒物,NO3^-、SO4^2-、F^-主要来自化石燃料燃烧及金属冶炼,重金属元素主要来源于燃煤以及人为活动污染。
Samples of precipitation collected during the period from March 2012 to February 2013 in Duyun City of Guizhou Province, a typical acid-rain area, and their distribution characteristics and possible sources of pH, anions, cations and heavy metals of precipitation were analyzed. The results showed that the precipitation of Duyun City has been acidified to some extent, and the samples with pH value being less than 5.6 account for 40.4%. SO4^2- and NO3^- are the major anions and their average concentrations are 180. 7 μmol/L and 50. 7 μmol/L, respectively. The ratios of SO4^2-/NO3^- range from 1.44 to 15.62, indicating that the precipitation of Duyun City belongs to sulfuric-nitric mixed acid rain. NH4^ ＋ is a major cation with an average concentration of 129.8 μmol/L, accounting for 50.8% of the total cations. The concentrations of main heavy metals （such as Cu, Zn, As, Cd, Pb, Cr） are relatively low, while the concentrations of Hg are higher than those of other cities. For seasonal variations, the concentrations of total ions are higher in winter and spring, but lower in summer and autumn. Correlation analysis showed that the chemical compositions of precipitation are mainly CaSO4, MgSO4 , NH4 SO4 and Ca（NO3 ）2. Ca^2＋ and Mg^2＋ are derived from terrestrial particles, NO3^ - , SO4^2- and F^- are mainly from fossil fuels and metal smelting, and heavy metals mainly stem from coal combustion and human activities.
出处
《地球与环境》
CAS
CSCD
北大核心
2014年第3期316-321,共6页
Earth and Environment
基金
贵州省环境保护厅环境科技项目(黔环科[2011]6号)
贵州大学研究生创新基金(研理工2013056)
关键词
大气降水
化学组成
来源分析
酸雨区
重金属污染
precipitation
chemical composition
source analysis
acid-rain area
pollution of heavy metals
