Effects of substrate type and arsenic dosage level on arsenic behavior in grassland microcosms. Part I. Preliminary results on 74As transport

Microcosm design is an important factor in interpreting results obtained from studies of the environmental effects, mobility and persistence of contaminants. The behavior of pentavalent arsenic and a radioarsenic tracer was studied in three substrate types exposed to differing levels of stable As dosage. Soil cores excised intact from a natural grassland ecosystem were considered to most reliably represent the natural system under study since they retained the soil structure, and closely simulated the abiotic and biotic complexity, of the grassland ecosystem. The behavior of 74As in the components of intact soil core microcosms differed appreciably from that observed for the other microcosm types where soil underwent manipulation. These differences were explained primarily on the basis of differences in soil structure