Assessment of Diffusion Gradients in Thin Films Technique for Measurement of the Arsenic Bioavailability in Soils

【Objective】This study was conducted to evaluate the feasibility and accuracy of bioavailable arsenic(As) measurement in soils using DGT(Diffusive Gradients in Thin Films Technique) and in further to shed light on the risk evaluation of As-contaminated soils.【Method】 A pot experiment was used to study the relationship between rape As in rape(Brassica campestris) and the effective concentration(CE) by DGT,soil solution As,NaHCO3-extracted As,NH4Cl-extracted As,and total soil As.Furthermore,the kinetic process of As transporting in soils was simulated using DIFS(DGT Induced Fluxes in Sediments and Soils) model and DGT data.【Result】A significant correlation between As contants in rape(B.campestris) and CE in soils was obtained with the coefficient determination(R2) of 0.990,and the results of DIFS model indicated that the shorter response time(Tc) and a higher desorption rate constants(kb) were both observed in the soils with a greater As bioavailibility.【Conclusion】 DGT was a reliable and an effective method for pre-concentration of bioavailable As and helped to elucidate the bioavailable process of As in soils on conjugation with the resupply parameters from DIFS model.