Biodegradation of imidacloprid in sandy loam soil by Bacillus aerophilus
Biodegradation of imidacloprid in sandy loam soil by Bacillus aerophilus
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DOI：
10.1080/03067319.2015.1055470
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发表时间：
2015-06-21
影响因子：
2.6
通讯作者：
Singh, Balwinder
中科院分区：
文献类型：
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作者：
Akoijam, Romila;Singh, Balwinder
在实验室条件下对吡虫啉在土壤中的生物降解进行了研究。用50、100和150mgkg(-1)的吡虫啉以及45×10(7)个嗜气芽孢杆菌菌落形成单位(CFU)强化沙土，并与未改良的土壤进行比较。样品用乙腈提取，用伯仲胺吸附剂和石墨化炭黑处理后净化。采用高效液相色谱法测定了吡虫啉及其代谢物的残留量。研究发现，吡虫啉的母体化合物在两种治疗中都更持久。在代谢物中，尿素和烯烃的含量最高，而5-羟基，6-氯烟酸(6-CNA)，亚硝胺和亚硝胺(NTG)也在所有处理中被检测到。在未改良(对照)土壤中，6-CNA是最持久的代谢物，其次是烯烃、尿素、5-羟基、亚硝胺和NTG代谢物。对照土壤中吡虫啉及其代谢物的总残留量在50和150mgkg(-1)时符合一级动力学，而在对照土壤中添加100mgkg(-1)时，吡虫啉及其代谢物的总残留符合准一级动力学。100mgkg(-1)和150mgkg(-1)的半衰期分别为25.08天和30.10天。然而，吡虫啉在土壤中的总残留量在50、100和150mgkg(-1)时均符合准一级动力学规律。50、100和150mgkg(-1)的半衰期分别为14.33、15.05和18.81天。结果表明，在嗜气性芽孢杆菌的作用下，3种剂量的吡虫啉在砂壤土中的减少率均高于对照。
A study of the biodegradation of imidacloprid in soil was carried out under laboratory conditions. Sandy soil samples were fortified with imidacloprid at 50, 100 and 150mgkg(-1) along with 45x10(7) colony forming units (cfus) of Bacillus aerophilus and the samples were compared with unamended soil. The samples were extracted with acetonitrile, cleaned up by treatment with primary secondary amine sorbent and graphitised carbon black. The residues of imidacloprid and its metabolites were analysed by high performance liquid chromatography. The parent compound, imidacloprid, was found to be more persistent in both the treatments. Among metabolites, the highest values were obtained for urea and olefin while 5-hydroxy, 6-chloronicotinic acid (6-CNA), nitrosimine and nitroguanidine (NTG) were also observed in all the treatments in amended soil. In case of unamended (control) soil, 6-CNA was found to be the most persistent metabolite followed by olefin, urea, 5-hydroxy, nitrosimine and NTG metabolites. Total imidacloprid residues for control soil samples followed first-order kinetics at 50 and 150mgkg(-1) but in case of control imidacloprid fortified at 100mgkg(-1), the total residues of imidacloprid and its metabolites followed pseudo-first-order kinetics. The respective half-life value for 50mgkg(-1) was 25.08days and 30.10days for both 100 and 150mgkg(-1). However, total imidacloprid residues followed pseudo-first-order kinetics for its applications at 50, 100 and 150mgkg(-1) in sandy loam soil amended with B. aerophilus. The half-life values for 50, 100 and 150mgkg(-1) were worked out to be 14.33, 15.05 and 18.81days, respectively. With the use of B. aerophilus, the reduction percentage of initial applied dose imidacloprid in sandy loam soil was found to be higher in all the three doses as compared to that of the control samples.