Fate of the veterinary antibiotic 14C-difloxacin in soil including simultaneous amendment of pig manure with the focus on non-extractable residues
Fate of the veterinary antibiotic 14C-difloxacin in soil including simultaneous amendment of pig manure with the focus on non-extractable residues
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DOI：
10.1080/03601234.2012.693868
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
Thorsten Junge;N. Classen;A. Schäffer;B. Schmidt
中科院分区：
文献类型：
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作者：
Thorsten Junge;N. Classen;A. Schäffer;B. Schmidt
采用时间过程试验研究了14 C-二氟沙星（14 C-DIF）在土壤中的残留行为（粉壤土Ap层）和添加猪粪的正宗DIF的改良（146 mL kg−1; 4.17 MBq kg−1; 0.85 mg kg−1）或水（124 mL kg−1; 0.42 MBq kg−1; 0.09 mg kg−1）分别孵育56天和120天。在56天或120天后，14 C-DIF的矿化在两个实验中均低于0.2%。在实验过程中，部分可提取的放射性（加速溶剂萃取（ASE）;乙腈-水）下降到19-21%，这仅取决于粪肥的修改。14 C-DIF在土壤中的非提取性残留分别在56天和120天后增加到70-74%，因此是14 C-DIF在土壤中的主要途径。根据放射性分析HPLC和LC-MS/MS，在整个实验时间内，在所有浸提液中仅发现母体化合物。根据分馏的不可提取的残留物（NER）到颗粒大小的部分，14 C部分相关的分馏，粉砂和粘土馏分所用的水，而在砂馏分中没有检测到放射性。大部分的14 C被发现在粘土馏分。腐殖酸组分的分馏表明，来自14 C-DIF的放射性与腐殖酸，富里酸，胡敏素和矿物质和非常小的可溶性，非腐殖酸盐酸馏分。在富里酸部分中发现了最高的放射性部分。通过纯化的富里酸的尺寸排阻色谱法（SEC）获得的结果对于分析的每个样品是相似的。大部分14 C与分子量低于910 g mol−1的富里酸共洗脱。这两种分馏方法表明，母体化合物DIF或初始代谢产物迅速整合到腐殖物质，因此，NER的主要成分。
The fate of 14C-labeled difloxacin (14C-DIF) was studied in time course experiments after application on soil (Ap horizon of silt loam) and amendment of authentic DIF containing pig manure (146 mL kg−1; 4.17 MBq kg−1; 0.85 mg kg−1) or water (124 mL kg−1; 0.42 MBq kg−1; 0.09 mg kg−1) for 56 and 120 days of incubation, respectively. Mineralization of 14C-DIF was below 0.2% in both experiments after 56 days or 120 days. In the course of the experiments, portions of extractable radioactivity (Accelerated Solvent Extraction (ASE); acetonitrile-water) decreased to 19–21% depending only little on manure amendment. Non-extractable residues of 14C-DIF increased to 70–74% after 56 days and 120 days, respectively, and therefore were the main route of 14C-DIF in soil. According to radioanalytical HPLC and LC-MS/MS, only the parent compound was found in all extracts over the whole time of the experiment. According to fractionation of the non-extractable residues (NER) into particle size fractions, 14C portions were associated to the water used for fractionation, the silt and clay fractions, whereas no radioactivity was detected in the sand fraction. The majority of 14C was found within the clay fractions. Fractionation of humic components showed that radioactivity derived from 14C-DIF was associated with humic acids, fulvic acids, humins and minerals and very little with soluble, non-humic HCl fraction. The highest portions of radioactivity were found in the fulvic acid fraction. Results obtained by size exclusion chromatography (SEC) of the purified fulvic acids were similar for every sample analyzed. One large portion of 14C co-eluted with fulvic acids of a molecular weight below 910 g mol−1. Both fractionation methods demonstrated that the parent compound DIF or initial metabolites were rapidly integrated into humic materials and, thus, were major components of NER.