Monitoring and Modeling the Effects of Groundwater Flow on Arsenic Transport in Datong Basin  

作　　者：Qian Yu Yanxin Wang Rui Ma Chunli Su Ya Wu Junxia Li 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies,China University of Geosciences

出　　处：《Journal of Earth Science》2014年第2期386-396,共11页地球科学学刊（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 40830748, 40902071 and 41120124003);the Ministry of Science and Technology of China (No. 2012AA062602);the Ministry of Education of China (111 project and Priority Development Projects of SRFDP)

摘　　要：Although arsenic-contaminated groundwater in the Datong Basin has been studied for more than 10 years, little has been known about the complex patterns of solute transport in the aquifer systems. Field monitoring and transient 3D unsaturated groundwater flow modeling studies were car- ried out on the riparian zone of the Sanggan River at the Datong Basin, northern China, to better un- derstand the effects of groundwater flow on As mobilization and transport. The results indicate that ir- rigation is the primary factor in determining the groundwater flow paths. Irrigation can not only in- crease groundwater level and reduce horizontal groundwater velocity and thereby accelerate vertical and horizontal groundwater exchange among sand, silt and clay formations, but also change the HS concentration, redox conditions of the shallow groundwater. Results of net groundwater flux estimation suggest that vertical infiltration is likely the primary control of As transport in the vadose zone, while horizontal water exchange is dominant in controlling As migration within the sand aquifers. Recharge water, including irrigation return water and flushed saltwater, travels downward from the ground surface to the aquifer and then nearly horizontally across the sand aquifer. The maximum value of As enriched in the riparian zone is roughly estimated to be 1 706.2 mg.d-1 for a horizontal water exchange of 8.98 m3.d-1 close to the river and an As concentration of 190 μg.L-1.Although arsenic-contaminated groundwater in the Datong Basin has been studied for more than 10 years, little has been known about the complex patterns of solute transport in the aquifer systems. Field monitoring and transient 3D unsaturated groundwater flow modeling studies were car- ried out on the riparian zone of the Sanggan River at the Datong Basin, northern China, to better un- derstand the effects of groundwater flow on As mobilization and transport. The results indicate that ir- rigation is the primary factor in determining the groundwater flow paths. Irrigation can not only in- crease groundwater level and reduce horizontal groundwater velocity and thereby accelerate vertical and horizontal groundwater exchange among sand, silt and clay formations, but also change the HS concentration, redox conditions of the shallow groundwater. Results of net groundwater flux estimation suggest that vertical infiltration is likely the primary control of As transport in the vadose zone, while horizontal water exchange is dominant in controlling As migration within the sand aquifers. Recharge water, including irrigation return water and flushed saltwater, travels downward from the ground surface to the aquifer and then nearly horizontally across the sand aquifer. The maximum value of As enriched in the riparian zone is roughly estimated to be 1 706.2 mg.d-1 for a horizontal water exchange of 8.98 m3.d-1 close to the river and an As concentration of 190 μg.L-1.

关 键 词：ARSENIC groundwater flow model Datong Basin. 

分 类 号：X523[环境科学与工程—环境工程]