AWWA JAW62925

This research describes the development of a dual preservation and field speciation technique for the arsenic species arsenite [As(III)] and arsenate [As(V)] using ion exchange field speciation of a sample preserved with EDTA and acetic acid. The new method is compared with existing speciation methods and is shown to be simple, robust, free of hazardous chemicals, and capable of recovering >90% of As(III) and As(V) despite possible interference from ferrous iron in the sample. The method was further refined through testing on 20 drinking water wells in five states. Results indicated that As(III) measured by field speciation agreed with subsequent lab speciation (conducted two to four days later) on the preserved sample with a correlation coefficient of R² = 0.997. Includes 31 references, tables, figures.