(PM091) Bioavailability of arsenic to edible plants grown in poultry litter applied soils.
Bloom, N1, Parker, J1, Gurleyuk, H1, 1 Frontier Geosciences, Seattle, WA, USA
ABSTRACT- The poultry industry is one of the largest and fastest growing livestock production systems in the world. Poultry is often treated with organo-arsenical feed additives used to control coccidial intestinal parasites, improve feed efficiency, and promote rapid weight gain. Since these arsenic compounds are not readily absorbed by poultry, poultry litter may contain as much as 30-50 mg As/kg. Approximately, 90% of the 13 million metric tons of poultry litter annually produced in the U.S. is applied as a fertilizer on cropland and pasture. There are already reports of high inorganic arsenic concentrations in rivers close to these chicken farms and chicken litter applied fields during/after storm events. Another important but unstudied aspect of this application is the possible accumulation of arsenic in agricultural plants. This study focuses on the bioavailability of As to various edible plants grown in soils amended with poultry litter. Arsenic speciation changes in the soil and plants over time was also monitored. For comparison, soils were also amended with inorganic As species and differences in plant bioavailability was assessed. In addition, we evaluated the ability of different leach solutions to target the desired As species, as well as a variety of chemical soil extractions to determine their usefulness in predicting plant bioavailable As in soils. Arsenic speciation was conducted using both ion chromatography - inductively coupled mass spectrometry (IC-ICP-MS) and hydride generation - cryogenic trapping - atomic absorption spectroscopy (HG-CT-AAS).
Key words: arsenic, bioavailability, roxarsone, poultry litter