Integrating compound-specific stable isotope and enantiomer-specific analysis to characterize the isomeric and enantiomeric signatures of hexachlorocyclohexanes (HCHs) in paddy soils

Muhammad Aamir; Zili Guo; Jiawei Yu; Lu Zhao; Dongmei Xu; Xiaohui Sun; Chao Xu; Lili Niu; Weiping Liu

doi:10.1016/j.jhazmat.2023.132196

Integrating compound-specific stable isotope and enantiomer-specific analysis to characterize the isomeric and enantiomeric signatures of hexachlorocyclohexanes (HCHs) in paddy soils

J Hazard Mater. 2023 Oct 5:459:132196. doi: 10.1016/j.jhazmat.2023.132196. Epub 2023 Jul 31.

Authors

Muhammad Aamir¹, Zili Guo¹, Jiawei Yu², Lu Zhao¹, Dongmei Xu³, Xiaohui Sun⁴, Chao Xu⁵, Lili Niu⁶, Weiping Liu⁷

Affiliations

¹ Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China.
² Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China; College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China.
³ College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China.
⁴ Zhejiang Environmental Monitoring Centre, Hangzhou 310012, China.
⁵ College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
⁶ Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China. Electronic address: niulili@zjsru.edu.cn.
⁷ Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China; MOE Key Laboratory of Environmental Remediation and Ecosystem Health, Institute of Environmental Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.

PMID: 37536155
DOI: 10.1016/j.jhazmat.2023.132196

Abstract

Organic pollutants in paddy fields may undergo different processes from those in dryland due to the anaerobic environment. The integrated use of compound-specific stable isotope analysis (CSIA) and enantiomer-specific analysis is a promising technique for understanding the behavior and fate of organic pollutants in soils. In this study, soil samples were collected from paddy fields in three major rice cultivation regions of China, spanning a transect of 4000 km. The mean concentrations of ƩHCHs in paddy soils from the Taihu Plain were the highest (1.44 ng/g). The ratios of α-HCH/β-HCH (all below 11.8) and α-HCH/γ-HCH (92% below 4.64), as well as the enantiomeric fractions (EFs) of chiral α-HCH (mean of 0.81), reflected that the distribution of HCHs was affected by the use of both technical HCHs and lindane. The preferential depletion of (-)-α-HCH and pronounced carbon isotope fractionation of α-HCH (δ¹³C of -28.22 ± 0.92‰ -23.63 ± 1.89‰) demonstrated its effective transformation. Factors such as altitude, soil temperature, soil pH, soil conductivity and soil organic matter significantly influenced the fate and transformation of HCHs. The current study highlights the integrated application of CSIA and enantiomer-specific analysis to provide multiple lines of evidence for the transformation of HCHs in soils.

Keywords: Agricultural Soil; Chiral compound; Persistent organic pollutant; Stable isotope; Transformation.