Microbial compositional and functional traits of BTEX and salinity co-contaminated shallow groundwater by produced water

Xianglong Chen; Yizhi Sheng; Guangcai Wang; Liang Guo; Hongyu Zhang; Fan Zhang; Tao Yang; Dandan Huang; Xu Han; Ling Zhou

doi:10.1016/j.watres.2022.118277

Microbial compositional and functional traits of BTEX and salinity co-contaminated shallow groundwater by produced water

Water Res. 2022 May 15:215:118277. doi: 10.1016/j.watres.2022.118277. Epub 2022 Mar 10.

Authors

Xianglong Chen¹, Yizhi Sheng², Guangcai Wang³, Liang Guo⁴, Hongyu Zhang¹, Fan Zhang¹, Tao Yang¹, Dandan Huang⁵, Xu Han⁶, Ling Zhou⁷

Affiliations

¹ State Key Laboratory of Biogeology and Environmental Geology & MOE Key Laboratory of Groundwater Circulation and Environment Evolution, China University of Geosciences, No.29, Xueyuan Road, Haidian District, Beijing 100083, PR China; School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China.
² State Key Laboratory of Biogeology and Environmental Geology & MOE Key Laboratory of Groundwater Circulation and Environment Evolution, China University of Geosciences, No.29, Xueyuan Road, Haidian District, Beijing 100083, PR China; School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China; Department of Geology and Environmental Earth Science, Miami University, OH 45056, USA. Electronic address: shengyz0330@163.com.
³ State Key Laboratory of Biogeology and Environmental Geology & MOE Key Laboratory of Groundwater Circulation and Environment Evolution, China University of Geosciences, No.29, Xueyuan Road, Haidian District, Beijing 100083, PR China; School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China. Electronic address: wanggc@pku.edu.cn.
⁴ College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, PR China.
⁵ School of Water Resources and Environmental Engineering, East China University of Technology, Nanchang 330013, PR China.
⁶ Geology Institute of China Chemical Geology and Mine Bureau, Beijing, PR China.
⁷ Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology, College of Water Sciences, Beijing Normal University, Beijing 100875, PR China.

PMID: 35305487
DOI: 10.1016/j.watres.2022.118277

Abstract

Intrusion of salinity and petroleum hydrocarbons (e.g., benzene, toluene, ethylbenzene, and xylenes, BTEX) into shallow groundwater by so-called 'produced water' (the water associated with oil and gas production) has recently drawn much attention. However, how this co-contamination affects the groundwater microbial community remains unknown. Herein, geochemical methods (e.g., ion ratios) and high-throughput sequencing (amplicon and shotgun metagenomic) were used to study the contaminant source, hydrogeochemical conditions, microbial community and function in salinity and BTEX co-contaminated shallow groundwater in an oil field, northwest China. The desulfurization coefficient (100rSO₄^2-/rCl^-), coefficient of sodium and chloride (rNa⁺/rCl^-), and coefficient of magnesium and chloride (rMg²⁺/rCl^-) revealed an intrusion of produced water into groundwater, resulting in elevated levels of salinity and BTEX. The consumption of terminal electron acceptors (e.g., NO₃^-, Fe³⁺, and SO₄^2-) was likely coupled with BTEX degradation. Relative to the bacteria, decreased archaeal diversity and enriched community in produced water-contaminated groundwater suggested that archaea were more susceptible to elevated BTEX and salinity. Relative to the nitrate and sulfate reduction genes, the abundance of marker genes encoding fermentation (acetate and hydrogen production) and methanogenesis (aceticlastic and methylotrophic) was more proportional to BTEX concentration. The produced water intrusion significantly enriched the salt-tolerant anaerobic fermentative heterotroph Woesearchaeia in shallow groundwater, and its co-occurrence with BTEX-degrading bacteria and methanogen Methanomicrobia suggested mutualistic interactions among the archaeal and bacterial communities to couple BTEX degradation with fermentation and methanogenesis. This study offers a first insight into the microbial community and function in groundwater contaminated by produced water.

Keywords: Functional genes; Microbial community; Oil contamination; Produced water; Salinity contamination; Shallow groundwater.

MeSH terms

Biodegradation, Environmental
Groundwater*
Salinity
Water
Water Pollutants, Chemical* / metabolism

Substances

Water Pollutants, Chemical
Water