EFFECT OF COMPLEXATION ON COPPER MOBILITY IN LANDFILL LEACHATE POLLUTED GROUNDWATER: A EXPERIMENTALLY VALIDATED CONCEPTUAL MODEL FOR MODELING HEAVY METALS TRANSPORT
Laboratory batch studies (two sandy aquifer materials, landfill leachate polluted groundwater with DOC (163 mg/l) and without DOC of salt matrix), ion-exchange speciation techniques and WHAM model (Tipping, 1994) speciation were conducted to investigate copper mobility in DOC contaminated groundwater in terms of Kd variation with pH to test the conceptual model. Also, Kd values and speciation from 82 copper contaminated soil samples reported in the literature were used to re-evaluate the conceptual model. The investigations confirmed the model was capable of predicting Kd values of copper, at a mean deviation of about 0.5 orders of magnitude at pH 5-8 in our study, and a fair prediction for a variety of contaminated soils at pH 5-8. Two empirical equations for Kd,ion values of copper correlated with pH at pH 5-8 were generated in this study for sandy aquifer materials and contaminated soils.
This study suggests that the combination of the conceptual model with empirical Kd,ion values might be an useful approach in a reactive transport model coupled with speciation model or geochemical model for modeling long-term metal contamination transport at field scale.