A major problem faced by utilities considering arsenic (As) adsorption media is that pilot testing requires very long runs and therefore is very costly. For example, a 200 mL lab scale column (5 cm diameter by 10 cm long) operated for 10,000 BVs at a 5 minute empty bed contact time (EBCT) requires a run length of 35 d and will use 500 L of water. An accelerated testing protocol is being developed to rapidly determine the adsorption characteristics of new media using procedures similar to those developed for granular activated carbon (GAC) adsorption which are referred to as rapid small scale column testing (RSSCT). Adsorption involves a sequence of steps including mass transfer processes and adsorption kinetics. For GAC, the intraparticle surface diffusion rate often controls the overall rate of adsorption, hence experiments conducted with smaller particles than used in a full scale adsorber can accelerate the testing process. Similitude was used to develop scaling relationships between laboratory columns and full scale GAC adsorption systems. There are important differences between adsorption of organics onto GAC and adsorption of As onto metal oxy-hydroxide surfaces. These include differences in the nature of the bonds and the internal pore structure of the adsorbents. These scaling relationships developed for GAC are being examined for As adsorption onto four metal oxide media; activated alumina, two iron oxy-hydroxide media, and a proprietary metal oxide media. The testing involves determination of the adsorption equilibria in batch studies, measurement of the intraparticle surface diffusion, and column studies using media of various sizes. The most important differences are the nature of the bonds and the physical characteristics of metal oxide adsorbents. In contrast to the hydrophobic bonds between organic solutes and GAC arsenic adsorption onto metal oxide surfaces is dominated by electrostatic attraction, at least initially. Also, metal oxide surfaces have much less internal porosity than GAC which results in less surface area and different types of mass transfer. Includes 16 references, tables, figures.