Geochemical characteristics of arsenic in groundwater during riverbank filtration: A case study of Liao River, Northeast China

Abstract

Affected by groundwater exploitation in the riverside, the infiltration of river water to recharge groundwater will cause changes in the groundwater environment, which has an important impact on the geochemical behavior of arsenic in groundwater. In this study, the groundwater environment zones in the process of river water infiltration were divided, and the arsenic content in groundwater in the study area had a good correlation with the environment zones. In the weak oxidation environment zone and the weak reductive environment zone, as the distance from the riverbank increased, the arsenic content gradually increased. In the reduction environment zone, there was a decreasing trend in arsenic content in groundwater. The arsenic content in groundwater varied significantly with the seasons, and its dynamic characteristics were closely related to the water level. The arsenic content in groundwater decreased with the rise in groundwater level, and it responded obviously to the change of water level in the shallows. Overall, arsenic entered the groundwater from the solid phase through adsorption and desorption of exchangeable arsenic and exchangeable iron, and reductive dissolution of iron or manganese oxides bound iron in the medium during riverbank filtration.