Chemical Distribution and Gaseous Evolution of Arsenic‐74 Added to Soils as DSMA‐74As

Abstract

AbstractGaseous evolution of 74 As from a soil treated with arsenic‐74 labeled disodium methanearsonate (DSMA‐74 As) at 100 µg/g was a function of organic matter addition and moisture conditions. Loss of 74As was greatest from soils that received an exogenous carbon source and were maintained under wet conditions.Arsenic‐74 sorbed by soils of pH 4, 6, and 8 was fractionated by a differential dissolution procedure commonly used for phosphorus. Iron arsenate (soluble in 0.1N NaOH) was the most abundant form followed by aluminum arsenate (soluble in 0.5N NH4F). The soils generally contained more aluminum arsenate at pH 4 than at pH 6 or 8. Calcium arsenate fractions (soluble in 0.5N H2SO4) were usually higher at pH 6 and 8 than at pH 4. Water‐soluble forms and nonextractable forms were inversely proportional to each other.