梧州市大气降水化学组分与离子平衡分析

Analysis of Ion Equilibrium and Chemical Components of AtmosphericPrecipitation in Wuzhou City

为了解梧州市大气降水阴、阳离子的平衡性,摸清各离子浓度对酸雨污染的影响,利用2023年3月~9月期间对梧州市3个降水自动采样点和1个手工监测点的大气降水样品开展降雨量、pH值、电导率、SO_(4)^(2-)、NO_(3)^(-)、F^(-)、Cl^(-)、NH_(4)^(+)、Ca^(2+)、Mg^(2+)、Na^(+)、K^(+)等常规项目监测,另外增加Br^(-)、NO_(2)^(-)、PO_(4)3^(-)、HCO_(3)^(-)、HCOO^(-)、CH3COO^(-)、SO_(3)2^(-)等离子项目进行实验室分析。结果表明:(1)HCOO^(-)、CH3COO^(-)等离子有助于提高阴阳离子浓度平衡合格率,有机酸对于降水酸性有一定的贡献作用;(2)总体上降水总离子浓度变化趋势与电导率变化趋势一致,酸根离子占比增大时pH值会下降;(3)SO_(4)2^(-)和NO_(3)^(-)仍是导致大气降水酸性的主要因子。

In order to understand the balance of atmospheric precipitation between cations and anions,and the impact of ion concentration on acid rain pollution in Wuzhou City,the monitoring of the regular items including precipitation volume,pH value,conductivity,SO_(4)^(2-),NO_(3)^(-),F^(-),Cl^(-),NH_(4)^(+),Ca^(2+),Mg^(2+),Na^(+),K^(+)were carried out for the atmospheric precipitation samples of three automatic sampling points and one manual monitoring point from March to September in 2023.In addition,Br^(-),NO_(2)^(-),PO_(4)^(3-),HCO_(3)^(-),HCOO^(-),CH3COO^(-),SO_(3)^(2-)and other related ions were analyzed in the laboratory.The results showed that:(1)HCOO^(-),CH3COO^(-)and other ions help to improve the qualified rate of balance between cations and anions.Organic acids have a certain contribution to the acidity of precipitation;(2)On the whole,the trend of changes in total ion concentration in precipitation is consistent with the trend of changes in conductivity.When the proportion of acid anions increases,pH value will decrease;(3)SO_(4)^(2-)and NO_(3)^(-)are still the main factors leading to acidity in atmospheric precipitation.