%0 Journal Article
%T Isomer, enantiomer and compound-specific stable isotope evidences for the transformation of dichlorodiphenyltrichloroethanes (DDTs) in soils from three typical paddy fields in China.
%A Guo Z
%A Gao X
%A Wang C
%A Liu S
%A Xu C
%A Mao S
%A Sun X
%A Niu L
%A Liu W
%J J Hazard Mater
%V 476
%N 0
%D 2024 Sep 5
%M 39029190
%F 14.224
%R 10.1016/j.jhazmat.2024.135233
%X Chlorinated pollutants may follow distinct degradation pathways in anaerobic environments compared to aerobic settings. However, the understanding of the behaviors and fate of dichlorodiphenyltrichloroethanes (DDTs) under anaerobic conditions remains limited. To address this knowledge gap, we conducted a study on flooded soil samples collected from three typical paddy fields in China using an integrated approach of enantiomer-specific analysis and compound-specific stable carbon isotope analysis. It is unexpected that the dichlorodiphenyldichloroethane /dichlorodiphenyldichloroethylene ratios (DDD/DDE=(o,p'-DDD+p,p'-DDD)/(o,p'-DDE+p,p'-DDE)) were below 1 in over 90 % of the samples. This might be attributed to the higher recalcitrance of p,p'-DDE, which concentrations were found to be 36 times higher than p,p'-DDD on average. There were 71.7 % of the samples showing enantiomeric fractions (EFs) of o,p'-DDT below 0.5, indicating a preferential accumulation of the (-)-enantiomer. The δ13C values of the anaerobic metabolite o,p'-DDD (-24.76 ± 1.35 ‰ to -34.39 ± 0.20 ‰) all deviated negatively from the initial product, while those of the aerobic metabolite o,p'-DDE (-23.61 ± 0.48 ‰ to -38.95 ± 0.81 ‰) displayed either negative or positive deviations. This demonstrates that o,p'-DDD is the primary metabolite of o,p'-DDT under anaerobic conditions. However, no clear correlations were observed between the δ13C and EF of o,p'-DDT. This study underscores the importance of such an integrated methodology in unraveling the fate and behaviors of DDTs in complex environmental systems.