Adsorption and degradation of two kinds of strobilurin fungicides in red soil from Jiangxi, black soil from Northeast China and paddy soil from the Taihu region were systematically studied through an in-lab simulation experiment, and their impacts on groundwater analyzed with GUS index.Results show that the two fungicides vary quite sharply in degradation rates, because they have different functional groups.Under room temperature and aerobic conditions, Picoxystrobin is fairly hard to degrade in the red soil and black soil, and hard to degrade pesticides in the paddy soil, while trifloxystrobin degrades easily in all the 3 types of soils.But under room temperature and anaerobic waterlogging conditions, picoxystrobin is moderate in degradability, while trifloxystrobin is high in all the three types of soils.Obviously, anaerobic waterlogging conditions facilitate degradation of the pesticides and anaerobia is an important factor affecting the degradation of strobilurin fungicides.Picoxystrobin is well adsorbed in the 3 types of soils, which fits the Freundlich equation well, with Koc being 811, 613 and 926 in the red soil, black soil and paddy soil, respectively, indicating that the soils are quite low in adsorption capability.Content of organic matter in the soil is the major factor affecting the soil′s capacity of adsorbing picoxystrobin.HPLC reveals that trifloxystrobin is higher than 20 000 in Koc indicating that trifloxystrobin belongs to the category of chemicals easily adsorbed.In all the three types of soils picoxystrobin varies between 1.8 and 2.8 in GUS index, indicating that the pesticide is leachable and poses a potential risk of polluting the groundwater, while trifloxystrobin is lower than 1.8 in GUS index, indicating that the chemical poses little pollution risk to the groundwater.%采用室内模拟试验,以江西红壤、东北黑土和太湖水稻土为代表性土壤,研究了啶氧菌酯和肟菌酯在土壤中的降解、吸附特性,并利用地下水污染指数(GUS)分析了其对地下水污染的影响.结果表明,杀菌剂的降解速率因含有的官能团不同而差异较大,常温、好氧条件下,啶氧菌酯在江西红壤和东北黑土中为较难降解性,在太湖水稻土中为难降解性,肟菌酯在上述3种土壤中均为易降解性;常温、积水厌气条件下,啶氧菌酯在江西红壤、太湖水稻土和东北黑土中均为中等降解性,肟菌酯在3种土壤中均为易降解性.积水厌气条件有利于啶氧菌酯和肟菌酯的降解,厌氧微生物是影响甲氧基丙烯酸酯类杀菌剂降解的重要因素.啶氧菌酯在江西红壤、东北黑土和太湖水稻土中的吸附均较好地符合Freundlich吸附等温方程,土壤有机碳分配系数(Koc)分别为811、613和926,属较难吸附等级,土壤有机质含量是影响啶氧菌酯在土壤中吸附性能的主要因素.采用高效液相色谱法估算可知,肟菌酯Koc>20 000,属易吸附等级.啶氧菌酯在3种土壤中的GUS值介于1.8~2.8,具有一定的淋溶性,对地下水具有一定的潜在污染风险;肟菌酯在3种土壤中的GUS值均<1.8,不淋溶,对地下水的潜在污染风险较小.
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