Abstract

Since a large part of heavy metals input in aquatic system accumulates in sediment, their concentrations in sediment are regarded as an important indicator of the heavy metal pollution of aquatic environment. The partition coefficient (K_d) is an empirical parameter that can represent the interaction of heavy metals at the sediment-water interface in aquatic system, however, it is not always stable with environmental conditions. Therefore, the introduction of K_d model with dominant physicochemical parameters would facilitate and improve the simulation of heavy metals concentrations in riverine sediment. The present study aims to develop a K_d model considering four physicochemical properties in stream water in order to simulate heavy metal concentrations in sediment of severely polluted urban rivers. Lead (Pb) concentrations in sediment of Harrach River, Algeria, were simulated using one-dimensional distributed hydrological model incorporating with presented K_d model. Multivariable equation of K_d model with physicochemical parameters (pH, suspended solid concentration (SS), chemical oxygen demand (COD) and biological oxygen demand (BOD)) was obtained from multiple regression analysis with observation data in various environmental condition. Hydrological simulations were tested with K_d model comparing to giving constant K_d. The numerical results agreed better with K_d model than with constant K_d, where the results accuracy increased from R2 0.05 for constant K_d to R2 0.67 for K_d model.