A study on kinetics and equilibrium is presented on the adsorption of arsenic species from simulated groundwater containing arsenic (As(III):As(V)::1:1), Fe and Mn in concentrations of 0.188 mg/L, 2.8 mg/L and 0.6 mg/L, respectively, by iron impregnated granular activated charcoal (GAC-Fe). Also presented is the interaction effect of As, Fe and Mn on the removal of arsenic species from water, Which simulates contaminated groundwater. Among conventional models, pseudo second-order kinetic model and Freundlich isotherm were adequate to explain the kinetics and equilibrium of adsorption process, respectively. However, in comparison to conventional isotherm empirical polynomial isotherm provided a more accurate prediction on equilibrium specific uptakes of arsenic species. Effects of initial concentrations of As, Fe and Mn on the removal of total arsenic (As(T)), As(V) & As(III) have been correlated within the error limit of -0.2 to +5.64%. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 1860-1871, 2009