|Lerch, Robert - Bob|
Submitted to: American Water Resources Association Spring Specialty Conference
Publication Type: Abstract only
Publication Acceptance Date: 11/20/2012
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Veterinary antibiotic (VA) presence in the environment, often associated with land application of manure, has generated significant interest in VA fate and transport in soil. However, few studies have focused on land management practices, such as vegetative filter strips, that might mitigate VA loss to water resources. Objectives of this study were to investigate the effects of vegetative management, soil properties, and dissolved organic matter (DOM) on sulfamethazine (SMZ) sorption to soil. Sorption experiments were performed over a range of SMZ concentrations (2.5 – 50 µmol L-1) using samples from three soils (Armstrong, Huntington, and Menfro) each planted to one of three vegetative treatments: agroforestry filter strip (ABS); grass filter strip (GBS); and row crop (RC) agriculture. Sorption isotherms were well fitted by the Freundlich isotherm model (log Kf = 0.44 to 0.93 and N = 0.59 to 0.79). Furthermore, evaluation of solid-to-solution distribution coefficients (Kd) indicated that vegetative management significantly (p < 0.01) influences SMZ sorption, following the order ABS > GBS > RC. Multiple linear regression analyses identified organic carbon (OC) content, pH, initial SMZ concentration, and clay content as important properties controlling SMZ sorption. Further study of SMZ sorption to the two most contrasting soils as a function of pH demonstrated decreased SMZ sorption to the smectitic, Armstrong GBS soil as pH increased from pH 6 to 7.5, but no substantial change in SMZ sorption with pH was observed for the kaolinitic, Huntington GBS soil. Presence of manure-derived dissolved organic matter (150 mg L-1 OC) had little effect on Freundlich model parameters, although DOM slightly reduced SMZ Kd values. These results support the use of vegetative filter strips for mitigating VA loss from agroecosystems, provide guidance for properly managing VBS to increase SMZ sorption, and enhance understanding of SMZ sorption in soils.