Fractions Transformation and Dissipation Mechanism of Dechlorane Plus in the Rhizosphere of the Soil-Plant System

Environ Sci Technol. 2020 Jun 2;54(11):6610-6620. doi: 10.1021/acs.est.9b06748. Epub 2020 Apr 10.

Abstract

The 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon
  • Hydrocarbons, Chlorinated* / analysis
  • Plant Roots / chemistry
  • Polycyclic Compounds
  • Rhizosphere
  • Soil
  • Soil Microbiology
  • Soil Pollutants* / analysis

Substances

  • Hydrocarbons, Chlorinated
  • Polycyclic Compounds
  • Soil
  • Soil Pollutants
  • dechlorane plus
  • Carbon