Biochar reduces antibiotic transport by altering soil hydrology and enhancing antibiotic sorption.

The performance of biochar (BC) in reducing the transport of antibiotics under field conditions has not been sufficiently explored. In repacked sloping boxes of a calcareous soil, the effects of different BC treatments on the discharge of three relatively weakly sorbing antibiotics (sulfadiazine, sulfamethazine, and florfenicol) via runoff and drainage were monitored for three natural rain events. Surface application of 1 % BC (1 %BC-SA) led to the most effective reduction in runoff discharge of the two sulfonamide antibiotics, which can be partly ascribed to the enhanced water infiltration.

[Effects of Biochar Application and Ageing on the Adsorption of Antibiotics in Purple Soil].

Effects of biochar application (at rates of 0%, 1%, and 5%) and field ageing (for 1 a) on the sorption of three antibiotics (sulfadiazine, sulfamethazine, and florfenicol) were studied by batch equilibrium tests for a calcareous purple soil of sloping cropland, which is widely distributed in hilly areas of the upper Yangtze River. A soil-water ratio of 1 g:1 mL, which was close to the actual field soil water content condition, was adopted in the experiment, and comparisons were made to the commonly used ratio of 1 g:10 mL. The results showed that adsorption isotherm data of the studied antibiotics were fitted well by the linear and Freundlich model, and the free energy (Δ) ranged from -0.