|Ong, Say Kee|
|Moorman, Thomas - Tom|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2005
Publication Date: 4/26/2005
Citation: Kolz, A.C., Ong, S., Moorman, T.B. 2005. Sorption of tylosin onto swine manure. Chemosphere. 60:284-289.
Interpretive Summary: The recent detection of antibiotics in stream waters has raised questions about the behavior of these chemicals in the environment. Tylosin is an antibiotic used in swine production. Tylosin is excreted by the animals and enters the environment during land application of manure. We found that tylosin is tightly bound to manure solids and to colloid particulates (ultra-fine solid materials) in swine manure lagoons. This fact suggests that tylosin leaching through soil will be minimized by this binding, except where large pores allow tylosin to move through the soil or in runoff attached to the colloid particulates. This also suggests that the soil materials at the bottom of the lagoons will contain more tylosin than the lagoon water. This knowledge will be used by agricultural and environmental scientists seeking to design practices that reduce manure impacts on water quality.
Technical Abstract: Sorption of tylosin was conducted on manure solids (< 2 mm) and colloidal materials (< 1.2 micrograms) collected from open (OL) and covered (CL) anaerobic swine manure lagoons. The aqueous concentration of tylosin in the sorption studies bracket the levels expected in lagoons, between 1 mg/L and 30 mg/L. Sorption isotherms were found to be slightly non-linear for 2-mm solids, with Freundlich distribution coefficients (Kf) of 39.4 with n = 1.32 for CL slurry and 99.5 with n = 1.02 for OL. These values are comparable to those reported for loam soils, but higher than those reported for sandy or clay soils and lower than those reported for fresh manure. Normalization of Kd to the organic carbon content of the solids gave Koc values of 570 L/kg and 818 L/kg, for CL and OL solids, respectively. Isotherms for colloids showed more non-linearity than 2-mm solids. The Kd and Kf values were not significantly different between colloids and 2-mm solids in OL slurry, but were significantly different in CL due to the non-linearity of the colloid isotherm.