HR: 0800h
AN: B51B-0370    [Abstracts]
TI: Geochemical fate of arsenic in swine litter
AU: * Quazi, S
EM: squazi@utsa.edu
AF: Environmental GEochemistry Laboratory University of Texas, San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Makris, K
EM: konstantinos.makris@utsa.edu
AF: Environmental GEochemistry Laboratory University of Texas, San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Sarkar, D
EM: dibyendu.sarkar@utsa.edu
AF: Environmental GEochemistry Laboratory University of Texas, San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Datta, R
EM: rupali.datta@utsa.edu
AF: Environmental GEochemistry Laboratory University of Texas, San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Punamiya, P
EM: pravin.punamiya@utsa.edu
AF: Environmental GEochemistry Laboratory University of Texas, San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AB: Swine diet is often supplemented by organoarsenicals, such as roxarsone to treat diseases and to promote growth. Recent data reported roxarsone degradation under anaerobic conditions in poultry litter, but no such data exist for swine wastes typically stored in unprotected lagoons in concentrated animal feeding operations (CAFOs). However, serious environmental health risk may arise upon significant arsenic (As) release into solution. The problem may be exacerbated under certain environmental conditions where organoarsenicals, such as roxarsone transform into the more toxic inorganic As, posing serious health risk to the surrounding ecosystem. The objective of this study were to analyze swine wastes collected from 19 randomly selected CAFOs in the USA for As concentrations, and to determine the geochemical fate of As in the swine waste suspensions. Swine wastes were analyzed for total-recoverable, total soluble, and water-extractable As, which were measured by ICP-MS. Speciation of As was performed following a well-established hyphenated technique using HPLC- ICPMS. Swine waste suspensions differed in solids contents; thus, the particulate matters with varying As concentrations were spiked with roxarsone and incubated under dark/light and aerobic/anaerobic conditions. Findings show the prevalence of inorganic As [As(V)] in swine waste suspension solutions. Roxarsone underwent degradation to both organoarsenicals, such as p-ASA, as well as inorganic arsenate and to a number of unidentified metabolites. Roxarsone degradation kinetics was influenced by the solids content and the air conditions (anaerobic/aerobic) of the swine waste suspensions. Maximum degradation rates were observed under anaerobic conditions, in suspensions which were low in solids content. Roxarsone degradation was primarily microbially-mediated, but in certain cases abiotic degradation was also observed, which were significantly slower.
DE: 0409 Bioavailability: chemical speciation and complexation
DE: 0463 Microbe/mineral interactions
DE: 0496 Water quality
DE: 1065 Major and trace element geochemistry
SC: Biogeosciences [B]
MN: 2007 Fall Meeting