| The subsurface partitioning and transport of trace metals such as copper (Cu(II)) are influenced by natural organic matter (NOM). Subsurface migration of contaminants involves adsorption and desorption of metals of organic species dissolved in water. Adsorption is of great importance in determining the magnitude and extent of soil and groundwater contamination.; In this research, experiments were designed to determine the effects of dissolved natural organic matter, simple inorganic ligands, divalent cations, and aluminum oxide mineral surfaces on the transport of Cu(II) in (saturated) groundwater. The NOM sources chosen for this research represent different NOM origins and evolutionary pathways. An NOM source designated as NOM-I was an injected surface water, injected into a shallow aquifer. The corresponding NOM source designated as NOM-B was derived from the injected water infiltrated through a shallow aquifer, and withdrawn/recovered as "breakthrough" water. Another NOM source, soil-derived humic acid, was used to represent soil organic matter prior to leaching through the vadose zone to groundwater.; Complexometric titrations, batch experiments, and column experiments were conducted to study the subsurface partitioning and transport of NOM in various binary systems (Cu(II)-NOM, Cu(II)-Mineral, and NOM-Mineral), as well as the ternary system (Cu(II)-NOM-Quartz and Cu(II)-NOM-Mineral). Data obtained were modelled by two advection/dispersion software packages, CFITIM and REACT programs, accounting for linear and nonlinear adsorption, respectively.; The results of this study showed: (1) hardness (Ca{dollar}sp{lcub}+2{rcub}{dollar}) can moderately affect the binding capacity of NOM, while Cu(II) addition significantly enhances the adsorption of NOM to minerals; (2) dissolved humic substances facilitate the transport of copper, while sorbed humic substances attenuate transport for Cu(II)-NOM-Mixed Mineral systems; and (3) time-dependent kinetic adsorption dominates the NOM-Mixed mineral system. |
