The influence of silicate on the adsorption and desorption of arsenite on goethite has been evaluated. Results from the current study indicate that previously adsorbed silicate inhibits the rate and total quantity of arsenite adsorbed on goethite. Furthermore, the formation of silicate polymers at higher loadings further reduced the total quantity and rate of arsenite adsorption. The addition of silicate to previously adsorbed arsenite results in a net desorption of arsenite. For arsenite adsorption and desorption the change in total quantity of arsenite adsorbed was always less than 8% of the total adsorbed in the absence of silicate. However, these relatively small changes in arsenite surface concentrations lead to dramatic changes in the solution concentration when compared to the drinking water MCL. Our findings suggest that anion displacement of adsorbed arsenite in contaminated environments may play a larger role in arsenite bioavailabilty than previously thought.