Arsenic distribution and geological factors in the western Jilin province, China

摘要

In order to elucidate the arsenic distribution and its relation with geological background in the western Jilin Province, China, groundwater and soil samples were collected from wells at different depths (6 to 160 m),and from surface soil (2-40 cm). Based on the sample tested, characteristics of high arsenic groundwater distribution are discussed. In the horizontal direction, arsenic concentrations that exceed the standards (China drinking water standards), were distributed in the Huolin River, Tao'er river ended area, the southern part of Taonan city, the central part of Tongyu county, and in the depression between the rivers and low plain in the northern part of the study area. While in the vertical profile, arsenic contents mainly exist in the phre-atic aquifer which are less than 20 m deep and are enriched in the confined aquifer between 20 and 100 m. In addition, groundwater hydrogeochemical features have also been discussed. The overlay function in the GIS is used to illustrate the relations between the geological background and arsenic distribution. From the arsenic distribution map with the tectonic, geology, soil and geomorphology map, the results show that arsenic in groundwater is closely related to the geological background, as the tectonic activity provided enough space, low-lying and closed environment to allow arsenic storage and enrichment At the same time, volcanic rock and fragmentary rock of Mesozoic supplies the material sources. The application of GIS to determine arsenic distribution and its relationship with geological factor is helpful in the understanding of the arsenic transport and enrichment.