Fractionation behaviors of Cu, Zn, and S-O isotopes in groundwater contaminated with petroleum and treated by oxidation

Duk-Min Kim; Woong-Lim Lim; Dae-Gyu Im; Jung-Woo Hwang; Soonyoung Yu; Seong-Taek Yun; Jeong-Hee Kim

doi:10.1016/j.jhazmat.2023.131901

Fractionation behaviors of Cu, Zn, and S-O isotopes in groundwater contaminated with petroleum and treated by oxidation

J Hazard Mater. 2023 Sep 15:458:131901. doi: 10.1016/j.jhazmat.2023.131901. Epub 2023 Jun 20.

Authors

Duk-Min Kim¹, Woong-Lim Lim², Dae-Gyu Im³, Jung-Woo Hwang⁴, Soonyoung Yu⁵, Seong-Taek Yun⁴, Jeong-Hee Kim⁶

Affiliations

¹ Department of New Energy and Mining Engineering, Sangji University, Wonju, Gangwon-do 26339, Republic of Korea. Electronic address: kdukmin8@sangji.ac.kr.
² Department of New Energy and Mining Engineering, Sangji University, Wonju, Gangwon-do 26339, Republic of Korea.
³ Department of New Energy and Mining Engineering, Sangji University, Wonju, Gangwon-do 26339, Republic of Korea; Department of Earth and Environmental Sciences, Korea University, Seoul 02841, Republic of Korea.
⁴ Department of Earth and Environmental Sciences, Korea University, Seoul 02841, Republic of Korea.
⁵ Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea.
⁶ Gyeonggi Regional Headquarter, Korea Rural Community Corporation, Suwon, Gyeonggi-do 16346, Republic of Korea.

PMID: 37356179
DOI: 10.1016/j.jhazmat.2023.131901

Abstract

Fractionation behaviors of Cu and Zn isotopes have been increasingly studied at the field scale, but those in various redox conditions of groundwater contaminated with petroleum and treated by oxidation have not been assessed. In this study, δ⁶⁵Cu and δ⁶⁶Zn as well as δ³⁴S_SO4 and Δδ¹⁸O_SO4-H2O were assessed in wells undergoing contamination by total petroleum hydrocarbons (TPH) and oxidation using H₂O₂ in 2021 and 2022. High δ³⁴S_SO4 and relevant parameters (e.g., dissolved sulfide and HCO₃^-) indicated the occurrence of sulfate reduction. The plot of δ⁶⁵Cu versus δ³⁴S_SO4 effectively indicated precipitation of Cu sulfides and their reoxidation at oxidation wells. Although the plot of δ⁶⁶Zn versus δ³⁴S_SO4 could also indicate reoxidation of Zn sulfides, the Zn isotopic fingerprint of sulfide precipitation may have been masked by fractionation by sorption. The advantage of using δ⁶⁵Cu in the redox reactions resulted from the wider range of δ⁶⁵Cu owing to the redox behavior of Cu. The plot combining isotopic fractionations of Cu and S can assist in assessing sulfide precipitation and oxidative treatment in TPH-contaminated groundwater.

Keywords: Oxidative treatment; Sulfate reduction; Sulfide oxidation; Sulfide precipitation; TPH.