微塑料影响下土壤中抗生素的解吸行为对抗生素迁移转化和生物有效性具有重要意义，本研究主要探讨不同类型微塑料对土壤抗生素解吸特征的影响。采用酸性水稻土为供试土壤，通过在土壤中添加33.4 mg·kg–1磺胺甲恶唑后老化5 d进行批平衡解吸试验。选择聚乙烯、聚苯乙烯、聚氯乙烯、聚丙烯、聚酯5种不同类型微塑料单一添加到供试土壤中，并调节不同氯化钠和富里酸浓度研究盐度和水溶性有机质探讨对土壤—微塑料混合体系中磺胺甲恶唑解吸行为的影响。结果显示：添加聚乙烯和聚苯乙烯微塑料可使土壤中磺胺甲恶唑的解吸速率降低，使土壤磺胺甲恶唑在10～48 h之间出现明显的慢解吸过程；并且添加聚乙烯和聚氯乙烯微塑料还能显著（P<0.05）降低溶液中磺胺甲恶唑的平衡解吸浓度。溶液的离子类型及其强度对供试土壤磺胺甲恶唑解吸的影响未受微塑料添加的影响，但体系中添加微塑料后可减小富里酸对土壤磺胺甲恶唑解吸的影响，使磺胺甲恶唑解吸量不会随着富里酸浓度的增加而降低。总体上，在土壤—微塑料混合体系下，微塑料可改变土壤抗生素的解吸，尤其是在富含水溶性有机质土壤中，微塑料的存在能增加抗生素解吸。因此，需要进一步关注微塑料对土壤抗生素迁移性和生物有效性的影响。
[Objective] Desorption of antibiotics in soils in the presence of microplastics is key to its migration, transformation, and bioavailability. The objective of this study was to reveal the desorption characteristics of sulfamethoxazole in an artificial antibiotic contaminated soil in the presence of five different microplastics.[Method] Batch equilibrium desorption experiments were carried out using an acid paddy soil that was spiked with 33.4 mg·kg–1 sulfamethoxazole and was aged for 5 days before use. Five polymeric microplastics including polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET) (1.67% and 3.33%). The microplastics were added to the soil individually and a soil:solution ratio of 1:10 was maintained in the experiment. The supernate was sampled for the sulfamethoxazole analysis using high-performance liquid chromatography (HPLC) from 0.25 to 96 h during the desorption kinetic experiment. Also, different concentration of NaCl and fulvic acid were added into the soil-microplastics mixture system to study the effect of salinity and dissolved organic matter (DOC) on sulfamethoxazole desorption, respectively.[Result] The results indicated that the desorption rate of sulfamethoxazole declined significantly and a slow desorption phase was observed from 10 h to 48 h after the addition of polyethylene and polystyrene microplastics. The equilibrium desorbed concentration of sulfamethoxazole declined significantly (P < 0.05) in the presence of polyethylene and polyvinyl chloride microplastics. The influence of sodium and calcium ions on sulfamethoxazole desorption from the soil was not affected by the addition of microplastics. However, the influence of fulvic acid on sulfamethoxazole desorption was mitigated after the addition of microplastics in general. Importantly, with an elevated concentration of fulvic acid, the decline of sulfamethoxazole desorption was negligible.[Conclusion] Generally, the desorption of sulfamethoxazole from soils was altered in the presence of microplastics. In soils with a relatively high concentration of DOC, elevated sulfamethoxazole desorption was observed. Therefore, this study highlights the migration and bioavailability of sulfamethoxazole in soils contaminated with microplastics and how different solvents influenced its desorption.
王佳青,俞奔,马绍峰,陈一阳,骆永明,章海波.土壤—微塑料混合体系中磺胺甲恶唑的解吸行为研究[J].土壤学报,2022,59(4):1048-1056. DOI:10.11766/trxb202101220038 WANG Jiaqing, YU Ben, MA Shaofeng, CHEN Yiyang, LUO Yongming, ZHANG Haibo. Desorption of Sulfamethoxazole from a Soil-Microplastics Mixture System[J]. Acta Pedologica Sinica,2022,59(4):1048-1056.复制