单 位：
陕西省河流湿地生态环境重点实验室/渭南师范学院化学与环境学院
关键词：
大气降水;化学特征;离子来源;气团轨迹;榆树沟流域;东天山
摘 要：
2013年5—8月按照GB13580.2-92规定的大气降水采样方法,采集了东天山喀尔力克山南坡榆树沟流域32场降水,进行了p H、EC及离子组成的测定,并运用综合描述法、相关性分析、气团来源轨迹、富集因子及端源贡献法探究其来源。结果表明:榆树沟流域夏季降水的p H平均值为6.8,呈弱酸性;电导率在3.79~239μs·cm~(-1),受降水量影响明显;阴阳离子质量浓度的平均值分别是SO_4~(2-)>NO_3~->Cl~->F~-和Ca~(2+)>NH_4~+>Na~+>K~+>Mg~(2+);SO_4~(2-)、NO_3~-、F~-和NH_4~+主要来自于人类活动;Cl~-基本来自海盐源,受地壳源的影响甚微;Na~+的来源受海盐源和陆源共同影响;Ca~(2+)和K~+来自于非海盐源的贡献。
译 名：
Chemical Properties of Summer Precipitation in the Yushugou River Basin in the East Tianshan Mountains
作 者：
WANG Xiao-yan;JIANG Chan-wen;College of Chemistry and Environment Sciences,Weinan Normal University/Key Laboratory for Ecology and Environment of River Wetlands in Shanxi Province;
关键词：
precipitation;;chemical property;;ion source;;air trajectories;;Yushugou River Basin;;East Tianshan
摘 要：
As an effective means to study the change of atmospheric chemical composition,atmospheric precipitation chemistry could accurately reflect the local atmospheric environmental quality and air pollution. The precipitation chemical properties far away from human colonies can reflect the background value of atmospheric chemistry,and can also help us to study the atmosphere chemical conversion,transmission and the formation process and mechanism of acid rain. Restricted by the seasonal precipitation distribution and the observation conditions in drainage basin,the p H value,EC and ion composition in precipitation in the Yushugou River Basin in the east Tianshan Mountains from May to August 2013 were analyzed. The ionic sources were simultaneously investigated. The results showed that precipitation was neutral with mean p H value of 6. 8. It suggested that there was no acid rain during the sampling period in the study area. The EC was in a range of 3. 79-239 μs·cm~(-1),and it was obviously affected by precipitation. With the increase of rainfall,the under cloud wash action diluted the conductive ions in precipitation,and the precipitation conductivity decreased correspondingly. The concentrations of cations and anions were in the orders of Ca~(2+)> NH_4~+> Na~+> K~+> Mg~(2+)and SO_4~(2-)> NO_3~-> Cl~-> F~- respectively. The cationic order was exactly the same as that of the elements in crust and different from that of cation concentration in seawater( Na~+>Mg~(2+)> Ca~(2+)> K~+). It may be due to the geographic location. The Yushugou River Basin is located in an arid area where large deserts are distributed. The SO_4~(2-)/NO_3~- ratio( 1. 76) indicated that SO_4~(2-) was the main acid-causing substance in precipitation. The sources of the different ions in summer precipitation were different. SO_4~(2-),NO_3~-,F~- and NH_4~+ came mainly from man-made sources,such as coal burning,vehicle emission and agricultural production activities. Cl-almost came from the sea salt source and crust source. The sodium concentration was mainly affected by sea salt,and a quite part of which was from terrigenous sources. Ca~(2+)and K+came from the non-sea-salt and affected mainly by the earth surface and human activities. In the study area,there were four water vapor paths including the northwest,southwest,southeast and north paths. Air mass from the northwest path originated from west Russia and Kazakhstan and passed through west Xinjiang. Water vapor originated from Mongolia passed across west Inner Mongolia with low population density and relatively underdeveloped economy. Human activities were frequent along the northwest path. There were the large deserts with alkaline soil along the northwest and north paths. Large amounts of alkaline substances were carried up to the atmosphere where alkaline substances could neutralize acid rain. Water vapor from the southwest path was from southwest inland of China and passed over the east Qinghai-Tibet Plateau. Vegetation in southwest inland grew well and less affected by human activities. Air mass along the southeast path was from the midwest region of China,and the vegetation coverage was very low,so precipitation was greatly influenced by terrigenous sources.
