生物质炭施用及老化对石灰性紫色土中磺胺类抗生素迁移特征的影响

以长江上游低山丘陵区广泛分布的石灰性紫色土旱地的耕作层土壤为对象,采用室内批量平衡吸附试验和填装土柱穿透试验,研究了施用1%生物质炭及3年老化作用对2种磺胺类抗生素(磺胺嘧啶和磺胺二甲基嘧啶)吸附和迁移特征的影响。结果表明,Freundlich方程能更好地拟合抗生素在土壤中的等温吸附曲线,施用生物质炭提高了土壤对抗生素的吸附能力,吸附常数KF值依次为:老化1%施炭土新鲜1%施炭土对照土;土柱出流液的磺胺嘧啶和磺胺二甲基嘧啶相对浓度峰值均表现为:老化1%施炭土新鲜1%施炭土对照土,说明生物质炭的添加能有效减少控制紫色土中抗生素的淋失迁移,以对磺胺二甲基嘧啶的阻控效果较好;生物质炭老化3 a后土壤对抗生素的吸附作用与阻控效果均有所提高,主要归因于土壤pH的提高。

Effects of Biochar Application and Ageing on the Transport of Sulfonamides in Calcareous Purple Soil

The effects of biochar addition (at rate of 1%) and field aging (for 3 years) on antibiotic transport were investigated in calcareous purple soil of farmland, which is distributed widely in the hilly areas of the upper Yangtze River. The sorption and transport of sulfadiazine and sulfamethazine in the soils were studied by batch equilibrium method and breakthrough experiments with repacked soil columns, respectively. The results showed that The isotherm adsorption data of both antibiotics were fitted better by the Freundlich equation. Biochar application improved the adsorption of both antibiotics to the soils, with the values of the Freundlich adsorption capacity (Kf) following the order: 1% biochar amended soil after 3 years of ageing > 1% fresh biochar amended soil > control soil. The peak relative concentrations of both antibiotics in the column effluents followed the order: 1% biochar amended soil after 3 years of ageing < 1% fresh biochar amended soil < control soil, indicating that biochar application could effectively reduce the leaching of the antibiotics. Field ageing enhanced the retention and transport of the two antibiotics in the soils, probably as the result of the observed increase in soil pH, and such effects were more pronounced for sulfamethazine than for sulfadiazine.