中国岩溶2018，Vol.37Issue(6)：875-882,8.DOI:10.11932/karst20180608
桂西北典型岩溶区水稻田成土剖面砷的垂向分布特征及其影响因素
Arsenic vertical distribution and its controlling factors in paddy soil profiles in a typical karst area, northwest of Guangxi, China
摘要
Abstract
The characteristics of topsoil soil arsenic (As) accumulation and vertical migration in karst areas is of great significance to understand the migration and transformation of soil As and its geochemical behavior in soil environment. To explore the concentrations and migration characters of As in karst region, three paddy soil profiles in a typical karst mining area, northwest of Guangxi, were investigated and analyzed. This study area is located in the Dachang mining area in the southwestern part of Nandan district, characterized by the south-middle subtropical monsoon climate. The contents of the soil samples collected from the soil profiles were analyzed in a geochemistry laboratory, where the soil As concentrations were analyzed using the atomic fluorescence spectrometric method; the concentrations of MgO, K2O, CaO and Na2O were analyzed using ICP spectrometric method; the soil organic carbon concentrations were analyzed using redox volumetric method; and the soil pH was analyzed using ion selective electrode method. Afterward, the statistical software SPSS was applied to perform the data analyses, combined with the background of study area. Results show that the soil profiles consists of limestone soils with high degree of chemical weathering originated from soil parent materials. The soil As concentration in all the profiles studied has similar character, with relatively high As levels near the surface which becomes stable at the deeper portions of the soil. The dominant controlling factor of As migration and transformation was considered to be the soil organic carbon. In the periphery of the mine, the analytical result of two soil samples shows that the soil As mainly concentrated at the depth of 10-20 cm, rather than 0-10 cm. The mean concentrations of soil As in these soil profiles are 5.5 mg·kg-1 and 5.0 mg·kg-1, respectively, with the ranges of 2.7 mg·kg-1-9.9 mg·kg-1 and 2.5 mg·kg-1-8.5 mg·kg-1. The soil As concentrations of the profile closer to the mining area are characterized by high As background value, and the mean concentration of soil As is 46.2 mg·kg-1 ranging from 34.2 mg·kg-1 to 84.5 mg·kg-1. The higher soil As concentrations in this soil profile gathers at the depth of 20-40 cm, while it is relatively lower in 10-20 cm deep. Notably, the soil As concentrations in this soil profile at 0-10 cm is also significantly higher than that of 10-20 cm deep, indicating that exogenous sources had significant effects on the surface soil of this profile. The ecological environment of karst mining area is extremely vulnerable, and the issue of agricultural soil As pollution in the surrounding areas should be paid sufficient attentions.关键词
岩溶/砷/土壤剖面/迁移/有机碳Key words
karst/Arsenic/soil profile/migration and transformation/soil organic carbon分类
资源环境引用本文复制引用
钟聪,王成,李杰,黄金兰,陈美君,何萍,张新英,胡宝清..桂西北典型岩溶区水稻田成土剖面砷的垂向分布特征及其影响因素[J].中国岩溶,2018,37(6):875-882,8.基金项目
国家自然科学基金(41867049) （41867049）
国家重点研发计划(2016YFC0502401) （2016YFC0502401）
广西自然科学基金(2016GXNSFBA380106,2018GXNSFAA281263) （2016GXNSFBA380106,2018GXNSFAA281263）
江苏省自然科学基金(BK20160947) （BK20160947）
广西中青年教师基础能力提升项目(2017KY0404) （2017KY0404）
