Distribution, influence factors, and biotoxicity of environmentally persistent free radical in soil at a typical coking plant

Qianqian Li; Lingwen Dai; Mengjing Wang; Guijin Su; Tieyu Wang; Xu Zhao; Xihui Liu; Yulin Xu; Jing Meng; Bin Shi

doi:10.1016/j.scitotenv.2022.155493

Distribution, influence factors, and biotoxicity of environmentally persistent free radical in soil at a typical coking plant

Sci Total Environ. 2022 Aug 20:835:155493. doi: 10.1016/j.scitotenv.2022.155493. Epub 2022 Apr 25.

Authors

Qianqian Li¹, Lingwen Dai¹, Mengjing Wang², Guijin Su³, Tieyu Wang⁴, Xu Zhao¹, Xihui Liu¹, Yulin Xu¹, Jing Meng¹, Bin Shi¹

Affiliations

¹ Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China.
³ Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: gjsu@rcees.ac.cn.
⁴ Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou 515063, China.

PMID: 35483459
DOI: 10.1016/j.scitotenv.2022.155493

Abstract

Environmentally persistent free radicals (EPFRs) are emerging pollutants in contaminated soils and have attracted significant attention. Chinese coke production making a great contribution to the globe is increasingly identified as the non-ignorable source of EPFRs. However, the distribution level, influence factors, and biotoxicity of EPFRs at coking sites remain poorly understood. Herein, a typical coking plant in Tangshan, China, featuring two functional regions (the reconstructed project (RP) and elimination engineering (EE)) was used to study the existence of EPFRs. The spin density of the EPFRs in coking soils was 3.20 × 10²⁰-3.11 × 10²¹ spins/g with g-factor values of 2.0020-2.0036. The EPFRs presented higher concentrations and g-factor values in RP region than in EE region, and a mixture of carbon-centered radicals and carbon-centered radicals with adjacent oxygen atoms as well as carbon-centered radical was ascertained in the former and the latter, respectively. Correlation analysis and FT-ICR-MS results indicated that polycyclic aromatic hydrocarbons (PAH) together with other unsaturated hydrocarbons and condensed aromatic contaminants, might contribute to the EPFRs formation in the soils of RP region, whereas PAHs were the main source of EPFRs in EE region. Soil components were determined to investigate the influence factors in EPFRs formation. Cu and Fe₂O₃ were recognized as the markedly positive influence factors, while TOC had a negative impact on EPFR formation. Visible light irradiation can induce the transformation and generation of EPFRs. As representative contaminants, both toluene and 2-chlorophenol can create EPFRs in coking soil under visible light irradiation. The potential biotoxicity tests of Photobacterium phosphoreum T3 spp. showed that EPFRs from the soils diminished bacterial luminescence. Such effect was proven to be induced by the OH based on the quenching experiment. Understanding the influence factors of EPFRs formation and their biotoxicity in coking soils is critical for developing risk assessments and prevention strategies.

Keywords: Biotoxicity; Coking soils; Distribution level; Environmentally persistent free radicals; Influence factors.

MeSH terms

Carbon
Coke* / analysis
Free Radicals / analysis
Polycyclic Aromatic Hydrocarbons* / analysis
Polycyclic Aromatic Hydrocarbons* / toxicity
Soil

Substances

Coke
Free Radicals
Polycyclic Aromatic Hydrocarbons
Soil
Carbon