Ground water samples obtained from West Bengal, India were analyzed for total arsenic and its inorganic species contents by
instrumental neutron activation analysis (INAA). Two anion exchange separation methods using Dowex 1X8 in chloride and acetate
forms were standardized for the speciation of As(III) and As(V) using radiotracers. The method by Dowex 1X8 in the acetate
form was validated using synthetic mixtures of As(III) and As(V), and applied to water samples; the species concentrations
were determined by INAA. The accuracy of the INAA method was evaluated by analyzing the NRCC CRM DORM-2 for total arsenic.