Aging affects isomer-specific occurrence of dechlorane plus in soil profiles: A case study in a geographically isolated landfill from the Tibetan Plateau

Ruwen Chang; Qi Wang; Xiyu Ban; He Zhang; Jun Li; Guo-Li Yuan

doi:10.1016/j.scitotenv.2023.163119

Aging affects isomer-specific occurrence of dechlorane plus in soil profiles: A case study in a geographically isolated landfill from the Tibetan Plateau

Sci Total Environ. 2023 Jun 20:878:163119. doi: 10.1016/j.scitotenv.2023.163119. Epub 2023 Mar 28.

Authors

Ruwen Chang¹, Qi Wang¹, Xiyu Ban¹, He Zhang¹, Jun Li², Guo-Li Yuan³

Affiliations

¹ School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
² School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China. Electronic address: junli@cugb.edu.cn.
³ School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.

PMID: 36996972
DOI: 10.1016/j.scitotenv.2023.163119

Abstract

Two major structural isomers in commercial dechlorane plus (DP) mixtures, anti-DP and syn-DP, generally displayed varied desorption and partitioning efficiencies in soils, which may be linked to their different aging rates. However, the molecular parameters that govern the degree of aging and its associated effects on the occurrence of DP isomers have not been comprehensively investigated. In this study, the relative abundance of rapid desorption concentration (R_rapid) was measured for anti-DP, syn-DP, anti-Cl₁₁-DP, anti-Cl₁₀-DP, Dechlorane-604 (Dec-604), and Dechlorane-602 (Dec-602) at a geographically isolated landfill area in the Tibetan Plateau. The R_rapid values were used as an indicator of aging degree, exhibiting a close correlation with the three-dimension conformation of the molecules for the dechlorane series compounds. This observation suggested that planar molecules may have a greater tendency to accumulate in the condensed phase of organic matter and undergo more rapid aging. The fractional abundances and dechlorinated products of anti-DP were found to be predominantly controlled by the aging degree of DP isomers. The multiple nonlinear regression model indicated that differences in aging between anti-CP and syn-DP were primarily driven by the total desorption concentration and soil organic matter content. Aging plays a significant role in both the transport processes and metabolism of DP isomers and should be taken into account to refine the assessment of their environmental behaviors.

Keywords: Aging; Dechlorane plus; Fractional abundance; Molecular descriptor; Tibetan Plateau.