Arsenate species are toxic compounds widely found as contaminants in industrial and metallurgical environments. Environmental health problems related to industrial waste streams and related drinking water contaminations can commonly occur. Around the world, from Bangladeshi water wells to Oklahoman metal plating sites, toxic levels of arsenic (As) leach into potable water. This paper describes a flow loop system that relies on magnetic nanoscale particles, iron oxide (nanorust), for the removal of these toxic metals. The nanorust particles have an extremely high surface area which allows for the rapid removal of these metal oxides. Perhaps even more importantly, nanorust (iron oxide) also has the unique advantage that it can be easily removed and re-concentrated using inexpensive low field magnetic (125 T) separation techniques. In this study we will present results on treating low levels of As in water with nano particles of mesh size at 50 nm and 26 nm. Determination of As concentrations below 100 ppb level was attained using an Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) system and a continuous flow loop system.