Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China

Yu, Kai1; Gan, Yiqun1; Zhou, Aiguo1; Liu, Chongxuan2; Duan, Yanhua1; Han, Li1; Zhang, Yanan1

2018-10

10.1016/j.chemosphere.2018.05.188

CHEMOSPHERE   影响因子和分区

0045-6535

1879-1298

Groundwater arsenic contamination is a common environmental problem that threatens the health of over 100 million people globally. Apparent seasonal fluctuations in groundwater arsenic concentrations have been reported in various locations worldwide, including the Jianghan Plain, central China. This phenomenon has been attributed to shifts in redox conditions induced by seasonal incursions of surface water. However, it is not clear what processes during the incursion lead to changes in the redox conditions and what is the source of the organic carbon driving these processes. Therefore, we conducted a long-term investigation of stable carbon isotopic compositions in surface water and groundwater, as well as long-term monitoring of hydraulic gradients and geochemical compositions at the Jianghan Plain. Results indicated that a series of biogeochemical processes occurred during surface water incursion, including aerobic microbial respiration, nitrate and sulfate reduction. Groundwater arsenic was removed by adsorption on iron oxyhydroxides produced during oxidation of ferrous iron, resulting in dramatic decreases in arsenic concentrations during surface water recharge seasons. These processes were likely driven by organic carbon vertically transported from surface water and released from the surficial aquitard above 15 m. Groundwater pumping may accelerate the vertical infiltration of oxidizing recharge water and drive exogenous organic carbon to depth. Findings of this study advance the understandings of the mechanisms that cause temporal variations in groundwater As and the importance of exogenous organic carbon that may influence the temporal behavior of arsenic in groundwater. (C) 2018 Elsevier Ltd. All rights reserved.

Seasonal fluctuations Groundwater arsenic Organic carbon Stable carbon isotope

SCI ; EI

英语

其他

Southern University of Science and Technology[GG01296001]

Environmental Sciences & Ecology

Environmental Sciences

WOS:000441999400086

PERGAMON-ELSEVIER SCIENCE LTD

20182705403714

Aquifers ; Arsenic ; Groundwater pollution ; Groundwater resources ; Infiltration ; Iron compounds ; Isotopes ; Organic carbon ; Sulfur compounds ; Surface waters

Surface Water:444.1 ; Groundwater:444.2 ; Chemical Products Generally:804 ; Organic Compounds:804.1

ENVIRONMENT/ECOLOGY

Web of Science

1.China Univ Geosci, Sch Environm Studies, Wuhan 430074, Hubei, Peoples R China
2.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Shenzhen 518055, Guangdong, Peoples R China

Yu, Kai,Gan, Yiqun,Zhou, Aiguo,et al. Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China[J]. CHEMOSPHERE,2018,208:773-781.

Yu, Kai.,Gan, Yiqun.,Zhou, Aiguo.,Liu, Chongxuan.,Duan, Yanhua.,...&Zhang, Yanan.(2018).Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China.CHEMOSPHERE,208,773-781.

Yu, Kai,et al."Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China".CHEMOSPHERE 208(2018):773-781.