|WATSON, JACK - Pennsylvania State University
|NELSON, SHAD - Texas A&M University
|WALKER, CHARLES - Us Geological Survey (USGS)
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2013
Publication Date: N/A
Interpretive Summary: The reuse of sewage effluent for irrigation is an effective way to increase water supplies in the desert southwest. Contaminants such as antibiotics, found in treated effluent, have been identified as a potential problem for use of this water for irrigation due to the potential for development of antibiotic resistance. Initial environmental fate parameters were determined for lincomycin in soils. It was found that lincomycin sorption is related to soil pH. When soil pH is below 7.6 lincomycin exhibits little sorption to soil, however, when soil pH is above 7.6 sorption of lincomycin is increased 10 fold. These results can be used to determine site-specific guidelines for disposal and use of reclaimed water.
Technical Abstract: The antibiotic lincomycin is commonly found in treated municipal waste water as well as waste from swine and poultry production. Environmental disposal of these wastes have the potential to introduce a significant mass of lincomycin into the ecosystem. In the present study a series of sorption and desorption experiments were conducted to determine the potential mobility of lincomycin in soils from arid environments. Sorption and desorption isotherms were obtained for lincomycin using three different soils. Isotherms were fit to the Freundlich equation. Adsorption of lincomycin was found to have a Kf of 11.98 for a biosolid treated soil (1.58% OC) and 210.15 to a similar unamended soil (1.42% OC). It was also found that for a low organic content soil the Kf was 5.09. The differences in adsorption can be related to the soil pH and the pKa of lincomycin (7.5-7.8). When the soil solution pH is below the pKa the cationic species of lincomycin dominates resulting in increased water solubility. Interaction with the cation exchange complex is minimal due to high solution cation concentration (Ca2+ and Na+). Desorption isotherms also indicate that when the solution pH is lower than the pKa retention of lincomycin is reduced. Results indicate that the mobility of lincomycin in these arid region soils will be dependent on soil pH.