Dissolved methane in groundwater of domestic wells and its potential emissions in arid and semi-arid regions of Inner Mongolia, China

Zhi-Ping Wang; Lin Zhang; Bin Wang; Long-Yu Hou; Chun-Wang Xiao; Xi-Mei Zhang; Xing-Guo Han

doi:10.1016/j.scitotenv.2018.01.205

Dissolved methane in groundwater of domestic wells and its potential emissions in arid and semi-arid regions of Inner Mongolia, China

Sci Total Environ. 2018 Jun 1:626:1193-1199. doi: 10.1016/j.scitotenv.2018.01.205. Epub 2018 Feb 19.

Authors

Zhi-Ping Wang¹, Lin Zhang², Bin Wang³, Long-Yu Hou², Chun-Wang Xiao⁴, Xi-Mei Zhang⁵, Xing-Guo Han⁶

Affiliations

¹ State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China. Electronic address: wangzp5@ibcas.ac.cn.
² State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China.
³ Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
⁴ College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China.
⁵ Key Laboratory of Dryland Agriculture, MOA, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
⁶ State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China; Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China; University of Chinese Academy of Sciences, Yuquanlu, Beijing 100049, China.

PMID: 29898526
DOI: 10.1016/j.scitotenv.2018.01.205

Abstract

Methane (CH₄) is widely present in groundwater. Dissolved CH₄ in groundwater is less understood when compared with that in wetlands. In this study, the concentrations and origin of dissolved CH₄ in groundwater were investigated and the potential importance of groundwater CH₄ emissions in arid and semi-arid regions of Inner Mongolia was discussed. Groundwater was extracted from domestic wells using a submersible pump or manual power and was analyzed for CH₄ concentrations, δ¹³C-CH₄, and physico-chemical variables. The results show that the concentrations of dissolved CH₄ in groundwater had large spatial variability, ranging from 0 to 0.10 mg L^-1 with a mean of 0.01 mg L^-1 in Xilingol and from 0 to 8.99 mg L^-1 with a mean of 1.44 mg L^-1 in Xingan-Tongliao. Substantial CH₄ concentrations of about 2.5-5.5 mg L^-1 were found in central areas of Xingan-Tongliao in the winter and the summer. The δ¹³C-CH₄ of about -85‰ was highly depleted while CH₄ concentration was significantly negatively correlated with SO₄^2- concentration, indicating that dissolved CH₄ in groundwater was microbial in origin. This study suggests that groundwater as a source of CH₄ might have great implications in arid and semi-arid regions worldwide and should deserve more research.

Keywords: Aquifer; Ground wetland; Isotope signature; Microbial CH(4); Sandy soils.