长期施用粪肥土壤中喹诺酮类抗生素的含量与分布特征

针对珠江三角洲地区长期施用粪肥的“无公害蔬菜”生产基地,利用固相萃取-高效液相色谱-串联质谱(LC-MS/MS)分析方法,探讨了土壤中喹诺酮类(QNs)抗生素4种化合物的含量与分布特征.结果表明,土壤中4种化合物的总含量(ΣQNs)为3.97~32.03μg/kg,平均17.99μg/kg.各化合物的检出率除了洛美沙星(92%)以外均为100%,最高含量为17.21μg/kg,平均含量为0.17~9.31μg/kg,以环丙沙星为主,其次是诺氟沙星和恩诺沙星.化合物的含量与组成特征无论在平面上还是在剖面上均存在明显的空间分布差异,且随着深度增加含量迅速降低,但在80cm深度仍有检出.珠江三角洲地区长期施用粪肥蔬菜基地土壤中喹诺酮类抗生素含量较低,土壤生态毒性风险较小,但各化合物均很高的检出率而导致的协同生态毒性尤其是耐药性问题值得进一步研究.

Concentration and distribution of quinolone antibiotics in long-term manure-amended soils

The concentration and distribution of quinolone antibiotics in soil of vegetable field chronically fertilized with manures was studied using solid-phase extraction followed by high-performance liquid chromatography- electrospray ionization tandem mass spectrometry. The total concentrations of four quinolone compounds ranged from3.97 to 32.03μg/kg with an average of 17.99μg/kg. There were very high detection rates (above 90%) observed for four compounds which dominated mostly with ciprofloxacin and secondly with norfloxacin and enrofloxacin. The concentrations of these compounds were all comparatively lower, with maximum concentration of 17.21μg/kg and average concentrations of 0.17~9.31μg/kg. There was obvious difference in spatial distribution of concentration and constitute of quinolone compounds in both horizontal and profile soil. All four compounds decreased rapidly with soil depth, but they were still detected at soil depths between 60 and 80cm. Quinolone antibiotics in soils from vegetable field chronically fertilized with manure in subtropical area were high frequently detected, but the concentration of them was comparatively lower and the ecotoxic risk was less owing to high degradation of antibiotics under hot and humid climate and heavy cultivation.