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Fractions Transformation and Dissipation Mechanism of Dechlorane Plus in the Rhizosphere of the Soil–Plant System
journal contribution
posted on 2020-04-10, 10:43 authored by Yu Cheng, Jue Ding, Xiuyu Liang, Xiaowen Ji, Ling Xu, Xianchuan Xie, You-Kuan ZhangThe
fractions transformation and dissipation mechanism of Dechlorane
Plus (DP) in the rhizosphere of soil–plant system were investigated
and characterized by a 150-day experiment using a rhizobox system.
The depuration, accumulation, and translocation of DP in rice plants
were observed. The contributions of plant uptake, microbial degradation,
and bound-residue formation to DP dissipation under the rhizosphere
effect were modeled and quantified. The gradients of DP concentrations
correlated well with microbial biomass in the rhizosphere (R2 = 0.898). The rhizosphere facilitated the
bioavailability of DP (excitation) and modified the bound-residue
formation of DP (aging). DP concentrations in roots were positively
correlated with the labile fraction of DP in soil (R2 = 0.852–0.961). There were spatiotemporal variations
in the DP fractions. Dissolved and soil organic carbon were important
influences on fraction transformation. Contributions to total DP dissipation
were in the following ranges: microbial degradation (8.33–54.14%),
bound-residue formation (3.64–16.43%), and plant uptake (0.54–3.85%).
With all of these processes operating, the half-life of DP in the
rhizosphere was 105 days. The stereoselectivity of DP isomers in both
rice and DP fractions in soil were observed, suggesting a link between
stereoselective bioaccumulation of DP in terrestrial organisms and
dissipation pathways in soil.