Antibiotics Transport in Different Soils Amended with Biochar.

Biochar as a soil amendment plays a potentially important role in the mobility of pollutants including antibiotics in soil and water environment. Among the antibiotics, tylosin is commonly used for human therapy and veterinary purposes as well as agricultural feed additives. However, few studies have examined how biochar influences the sorption/desorption and transport of antibiotics. In this study, two biochars were characterized for their phyico-chemical properties. We compared tylosin retention and transport in two different soils (corn field and forest soil) with four different application rate of biochar. Kinetic batch type and column experiments were carried out to understand retention and transport behavior of tylosin with the amendment of different biochars. Sorption isotherms of tylosin on biochar amended soils can be well described by a Freudlich model. The Kf values were compared among the treatments. Additionally, desorption hysteresis were characterized. The computer program CXTFIT was used to fit the breakthrough data of tylosin in transport with linear/nonlinear sorption. These research findings are of importance to an assessment of the fate and transport of tylosin in soil system under different environmental conditions.