Molecular fractionation mediates genotoxicity evolution of hydrochar-derived dissolved organic matter at the iron oxyhydroxides-water interface

Yan-Jun Liu; He-Yun Yang; Shu-Xian Gao; Zheng-Hao Li; Yan-Yun Hu; Xing Zheng; Guo-Ping Sheng

doi:10.1016/j.watres.2024.122584

Molecular fractionation mediates genotoxicity evolution of hydrochar-derived dissolved organic matter at the iron oxyhydroxides-water interface

Water Res. 2024 Oct 6;268(Pt A):122584. doi: 10.1016/j.watres.2024.122584. Online ahead of print.

Authors

Yan-Jun Liu¹, He-Yun Yang², Shu-Xian Gao³, Zheng-Hao Li⁴, Yan-Yun Hu⁵, Xing Zheng², Guo-Ping Sheng⁶

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
² State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an 710048, China.
³ Research Group BioGeoOmics, Department Environmental Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, Leipzig D-04318, Germany.
⁴ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China. Electronic address: lizhhao@ustc.edu.cn.
⁵ Instruments Center for Physical Science, University of Science and Technology of China, Hefei 230026, China.
⁶ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China. Electronic address: gpsheng@ustc.edu.cn.

PMID: 39395367
DOI: 10.1016/j.watres.2024.122584

Abstract

Adsorption fractionation of dissolved organic matter (DOM) induced by soil minerals is a common geochemical process, which has been widely documented on natural DOM. Hydrochar is a promising functional material in soil remediation but can continuously release abundant endogenic DOM with potential biotoxicity. However, adsorption fractionation at molecular level and its influence on toxicity evolution of hydrochar-derived DOM (HDOM) at genetic level at the soil-water interface remain poorly understood. Herein, we investigated the molecular fractionation of HDOM on three typical soil iron minerals (i.e., ferrihydrite, goethite, and hematite). Results from ultrahigh-resolution mass spectrum showed that HDOM molecules with high molecular weight and high contents of unsaturated oxidized or aromatic structures (e.g., unsaturated phenolic compounds, polyphenols, and organic acids) were preferentially absorbed by iron oxyhydroxides, while aliphatic molecules and poorly oxygenated compounds (e.g., hydrocarbon, phenols, and alcohols) were retained in aqueous phase. Furthermore, we quantitatively evaluated their genotoxicity variation using a toxicogenomics assay using green fluorescence protein-fused whole-cell array, and results showed that oxidative, protein, membrane, and DNA stresses were primary responses upon exposure to original HDOM. Interface fractionation induced by iron oxyhydroxides significantly reduced genotoxicity of HDOM, especially for oxidative, membrane and DNA stresses. Overall, the selective absorption of HDOM molecules by iron oxyhydroxides shifted its biotoxicity, which might change the ecological effects of hydrochar amendment, e.g., microbial community structure, environmental pollutant transformation, and even the ecological function of terrestrial and aquatic ecosystems. These findings would contribute to unraveling the environmental geochemistry process of HDOM in the natural soil-water interface and provide a new insight into the biotoxicity of hydrochar usage to terrestrial and aquatic environments.

Keywords: Dissolved organic matter; Hydrochar; Molecular fractionation; Soil-water interface; Toxicogenomics assay.