RESUMEN
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. The construction of 5 % BC amended permeable reactive wall (5 %BC-PRW) at the lower end of soil box was more effective than the 1 %BC-SA treatment in reducing the leaching of the most weakly sorbing antibiotic (florfenicol), which can be mainly ascribed to the much higher plant available and drainable water contents in the 5 %BC-PRW soil than in the unamended soil. The results of this study highlight the importance of BC's ability to regulate flow pattern by modifying soil hydraulic properties, which can make a significant contribution to the achieved reduction in the transport of antibiotics offsite or to groundwater.
Asunto(s)
Antibacterianos , Carbón Orgánico , Contaminantes del Suelo , Suelo , Antibacterianos/química , Carbón Orgánico/química , Adsorción , Suelo/química , Contaminantes del Suelo/química , Contaminantes Químicos del Agua/química , Movimientos del Agua , Agua Subterránea/química , Tianfenicol/análogos & derivados , Tianfenicol/químicaRESUMEN
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 (ΔGθ) ranged from -0.39 to 11.53 kJ·mol-1, thus indicating that the adsorption of the three antibiotics on the control soils and biochar amended soils was mainly physical adsorption. Application of fresh biochar was found to markedly enhance the adsorption of antibiotics, especially for sulfamethazine and florfenicol of low Kow values, while such an effect was strongly weakened after ageing. The fluorescence peak response intensity of the adsorption equilibrium solution of the aged biochar amended soil was lower than that of the fresh biochar amended soil, so the difference in adsorption performance between fresh and aged biochar amended soils may have been due to the decrease of unstable and soluble organic matter in the latter's biochar after aging.