Effect of electric fields strength on soil factors and microorganisms during electro-bioremediation of benzo[a]pyrene-contaminated soil

Fengmei Li; Jingming Li; Menghan Tong; Kailu Xi; Shuhai Guo

doi:10.1016/j.chemosphere.2023.139845

Effect of electric fields strength on soil factors and microorganisms during electro-bioremediation of benzo[a]pyrene-contaminated soil

Chemosphere. 2023 Nov:341:139845. doi: 10.1016/j.chemosphere.2023.139845. Epub 2023 Aug 25.

Authors

Fengmei Li¹, Jingming Li², Menghan Tong², Kailu Xi², Shuhai Guo³

Affiliations

¹ Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; National-Local Joint Engineering Laboratory of Contaminated Soil Remediation By Bio-physicochemical Synergistic Process, Shenyang 110016, China.
² Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China.
³ Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; National-Local Joint Engineering Laboratory of Contaminated Soil Remediation By Bio-physicochemical Synergistic Process, Shenyang 110016, China. Electronic address: shuhaiguo@iae.ac.cn.

PMID: 37634583
DOI: 10.1016/j.chemosphere.2023.139845

Abstract

Electro-bioremediation is a promising technology for remediating soils contaminated with polycyclic aromatic hydrocarbons (PAHs). However, the resulting electrokinetic effects and electrochemical reactions may inevitably cause changes in soil factors and microorganism, thereby reducing the remediation efficiency. To avoid negative effect of electric field on soil and microbes and maximize microbial degradability, it is necessary to select a suitable electric field. In this study, artificial benzo [a]pyrene (BaP)-contaminated soil was selected as the object of remediation. Changes in soil factors and microorganisms were investigated under the voltage of 1.0, 2.0, and 2.5 V cm^-1 using chemical analysis, real-time PCR, and high-throughput sequencing. The results revealed noticeable changes in soil factors (pH, moisture, electrical conductivity [EC], and BaP concentration) and microbes (PAHs ring-hydroxylating dioxygenase [PAHs-RHDα] gene and bacterial community) after the application of electric field. The degree of change was related to the electric field strength, with a suitable strength being more conducive to BaP removal. At 70 d, the highest mean extent of BaP removal and PAHs-RHDα gene copies were observed in EK2.0 + BIO, reaching 3.37 and 109.62 times those in BIO, respectively, indicating that the voltage of 2.0 V cm^-1 was the most suitable for soil microbial growth and metabolism. Changes in soil factors caused by electric fields can affect microbial activity and community composition. Redundancy analysis revealed that soil pH and moisture had the most significant effects on microbial community composition (P < 0.05). The purpose of this study was to determine the appropriate electric field that could be used for electro-bioremediation of PAH-contaminated soil by evaluating the effects of electric fields on soil factors and microbial communities. This study also provides a reference for efficiency enhancement and successful application of electro-bioremediation of soil contaminated with PAHs.

Keywords: Benzo[a]pyrene; Electric field; Electro-bioremediation; Microbial; Polycyclic aromatic hydrocarbons; Soil.

MeSH terms

Benzo(a)pyrene / analysis
Biodegradation, Environmental
Polycyclic Aromatic Hydrocarbons* / analysis
Soil / chemistry
Soil Microbiology
Soil Pollutants* / analysis

Substances

Soil
Benzo(a)pyrene
Soil Pollutants
Polycyclic Aromatic Hydrocarbons