摘要
对采集于重庆市北碚区2009年10月-2010年8月的48场雨水样品进行Cl-,NO3-,SO24-以及pH值和电导率(EC)的测试分析,发现该地区雨水中pH值变化范围为4～7.73,EC变化范围为14～379μs/cm,出现酸雨的频率为46%,并且在不同季节均可出现;每场降雨中离子质量浓度的不同及离子间的相互作用决定其pH值和EC的变化,但是两者不具相关性;雨水中Cl-,NO3-,SO24-三种离子质量浓度的总和变化范围为4.61～178.84mg/L,相互之间具有明显的相关性,并且这三种主要阴离子的质量浓度与雨水的EC呈显著相关性,体现出"夏季偏低,冬季偏高"的时间变化特征.这是由于夏季降水量较多,其稀释效应导致这些酸根离子质量浓度在夏季降水中浓度降低,而冬季由于降水量较少,雨水中的这些酸根离子质量浓度相对升高.SO24-为雨水中主要的致酸离子,与该地区以煤为主的能源结构一致.
An investigation of the concentrations of Cl- , NO（^-,3） and SO（^（2-）,4） , and on the monitored values of pH and electrical conductivity （EC） from the rainwater collected in 48 precipitation events during the period from October, 2009 to August, 2010 in Beibei district, Chongqing showed that the variation range of rainwater pH and EC were from 4 to 7.33 and from 14 to 379 μs/cm respectively. Acid rain occurred in various seasons of the year with a total frequency of 460/00. The changes in pH and EC of the rainwater were determined by the difference in ion concentrations and the interactions among the ions in rainwater during every precipitation. However, there was no significant relevance between the pH and EC proxies. The summations （∑） of the concentration ofCl- , NO（^-,3） and SO（^（2-）,4） anions in rainwater changed from 4.61 to 178.84 mg/L, and there were significant correlations among these anions. ∑, was significantly correlated with EC of rainwater and characterized by ing the winter months, which might be at hig trib her values during the summer months and lower values dur uted to the dilution effect of rainwater during rainy summer and the accumulation of atmospheric impurity during cing anion for the rainwater in Chongqing area, which composition structure. winter. SO（^（2-）,4） proved to be the dominant acid-indu cing anion for the rainwater in Chongqing area, which was consistent with the local coal-dominated energy composition structure.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2012年第2期105-113,共9页
Journal of Southwest University(Natural Science Edition)
基金
国家自然科学基金资助项目(40802035
40971122
41030103
41172165)
黄土与第四纪地质国家重点实验室开放基金资助项目(SKLLQG0907)
西南大学基本科研业务费专项资金重点资助项目(XDJK2009B016
XDJK2009C106)
关键词
北碚
大气降水
酸根离子
大气污染
Beibei district
meteoric precipitation
acid radical ion
air pollution
