Arsenic mobilization in the piedmont area of the Hetao basin: an insight from a reactive transport model

Zhipeng Gao, Huaming Guo, Di Zhang, Bo Zhao, O. Shouakar-Stash, O. Chudaev, R. Millot, R. Harmon, Y. Kharaka
2019 E3S Web of Conferences  
Groundwater showed a trend from oxic-suboxic conditions in the alluvial fan to anoxic conditions in the flat plain in the Hetao basin, with increases in As, Fe2+, NH4+, alkalinity and pH, and decreases in Eh and NO3-. A 1D reactive transport model was constructed using a model flow column by PHREEQC to quantitatively interpret geochemical processes related to As mobilization in a 5000 m-long hydrogeological unit. Results indicated that groundwater As concentration was mostly controlled by
more » ... controlled by Fe(III) oxide reduction and As adsorption processes. Observed Fe2+ was the combination of Fe(III) oxide reduction and mackinawite/siderite precipitation. Increasing alkalinity was the result of oxidation of organic carbon, rather than the dissolution of carbonates.
doi:10.1051/e3sconf/20199805008 fatcat:s5nlwf4qivcqnko3v3rfzj7gvi