Sorption of Lincomycin Antibiotics By Manure-Derived Biochars.

Lincomycin is widely used in animal feeding operations for disease prevention and livestock growth promotion. Lincomycin is only partially metabolized after administration to animals, and the residual lincomycin is excreted. Consequently, lincomycin may enter the environment through land-applied animal manure. The presence of lincomycin in the environment raises serious concerns for the proliferation of antibiotic resistant genes in bacteria and potential negative health effects to humans. To develop mitigation strategies, a better understanding of mechanisms controlling environmental fate and transport of lincomycin is urgently needed. Biochars are carbon-enriched porous materials produced from a variety of biomass or agricultural waste, and are promoted as soil amendments for agronomic and environmental benefits, including in-situ contaminant immobilization. In this study, lincomycin sorption by manure-derived biochars was examined in detail using batch sorption experiments. Sorption kinetic results indicate lincomycin sorption process is characterized by fast and slow sorption stages. Lincomycin sorption on biochars occurred rapidly for the first hour, and reached the plateau of the fast stage in two days. The lincomycin sorption increased continuously and did not reach equilibrium by the end of study period (i.e., 6 months). The fast sorption may be primarily from surface sorption, i.e., lincomycin being sorbed on external surface of biochars. The long-term slow sorption is considered to be controlled by pore-filling processes, through which lincomycin penetrates deeply into the pore structure of biochars. The sorption experiment results showed that biochar had high lincomycin sorption capacity, implying that the distribution and transport of lincomycin in the environment will be profoundly impacted by biochar. Therefore, land application of manure-derived biochars may have beneficial consequences, through decreasing bioavailability and mobility of lincomycin in the environment.