Investigating the Abiotic Mechanism of Veterinary Antibiotics Influencing Boron and Molybdenum Cycling in the Environment
Veterinary antibiotics and micronutrient can co-exist in the soil environment in situations in which livestock manure is applied to agricultural lands, fertilizer application is followed by manure application, or when agricultural lands are irrigated with surface or groundwater contaminated with antibiotics. In these scenarios, strong retention of these antibiotics on soil minerals can potentially influence the biogeochemical cycling of micronutrients such as boron (B) and molybdenum (Mo). Thus, detailed evaluation of B and Mo sorption mechanisms in single ion and in a competitive sorption scenario is vital to predicting their mobility in the soil environment. This study evaluated B and Mo competitive adsorption with selected veterinary antibiotics (oxytetracycline and tylosin) on hematite as a function of pH and initial B, Mo and OTC/TYL concentrations using macroscopic sorption studies, and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to understand the surface interaction mechanisms. The major IR bands of sorbed B indicated that sorption occurred via inner-sphere and outer-sphere complexation mechanism, while for Mo, inner-sphere surface complex is most likely the predominant mechanism of interaction. OTC interacted with the hematite surface through – CONH2, - N(CH3)2, and the phenolic- OH functional group as indicated by the major OTC IR bands, while TYL interacted with the hematite surface primarily through the - N(CH3)2 and the phenolic- OH functional group. For binary systems, the major IR bands of sorbed B was affected in the presence of OTC. B retention had minor effect on TYL sorption. For Mo and OTC/ TYL competitive sorption, the major IR bands indicative of Mo sorption on hematite was affected due to OTC/TYL retention. Macroscopic sorption results of B and OTC, and B and TYL competition are consistent with the spectroscopic results. However, macroscopic competitive sorption results of Mo and OTC did not show clear evidence of OTC effect on Mo sorption, although minor effect was observed at lower pH values. These findings are important for predicting micronutrients availability in agricultural lands where animal manure is used as a major source of nutrient or as a complementary to inorganic or chemical fertilizers
Environmental science|Agronomy|Soil sciences
"Investigating the Abiotic Mechanism of Veterinary Antibiotics Influencing Boron and Molybdenum Cycling in the Environment"
ETD Collection for Tennessee State University.