Dynamic simulation of the release of Pb from sediments
沉积物中重金属铅的释放动力学模拟

A DIFS model was used to investigate the kinetics of release of Pb from sediments.The simulation results show that in a sustained case (sample S1,R→1) ,when the dissolved Pb adjacent to DGT (diffusive gradient in thin films) was depleted,the re-supply from the sediment was sufficiantly fast to maintain the Pb concentration in the pore water to its initial level as the labile content of Pb and the deserption coefficient,k_(-1) were high.For sample S2 (R→0,a non-sustained case),the re-supply from sediment was very low,as the labile content of Pb was low and Pb concentration in the pore water adjacent to the DGT device was progressively depleted.For sample 33 (a partial sustained case,R =0.39) ,the re-supply from sediment was between 31 and S2,as the intermediate labile Pb content and k_(-1).As a result,the release of Ph from the sediments was influenced by the pool of labile Pb and the kinetic parameters of the release.