摘要
研究了室外条件下河水和海水中三环唑、氟环唑和苯醚甲环唑的非生物降解(光解和水解)行为,并考察了室内条件下硝酸盐、腐殖酸和颗粒物对光解的影响.结果表明,3种目标农药在水环境中的非生物降解(光解和水解)动力学符合一级动力学模型.在厦门夏季室外条件下(平均气温25—32℃),河水中三环唑、氟环唑和苯醚甲环唑的非生物降解半衰期(t1/2)分别为17.6—49.8 d、25.6—90.5 d、16.5—42.6 d,光解t1/2分别为19.9—73.6 d、28.0—131.8 d、17.6—50.5 d,水解t1/2分别为154.0 d、288.8 d、271.8 d;海水中三环唑、氟环唑和苯醚甲环唑的非生物降解t1/2分别为22.8—48.1 d、74.8—93.8 d、37.2—48.4 d,光解t1/2分别为34.1—160.6 d、113.4—163.8 d、87.4—193.0 d,水解t1/2分别为68.6 d、219.7 d、64.6 d.目标农药的光解在非生物降解中占主导地位,河水中的光解速率普遍快于海水.pH升高促进三环唑和苯醚甲环唑的水解,但抑制氟环唑的水解.室内实验发现,硝酸盐抑制目标农药的光解,腐殖酸抑制氟环唑和苯醚甲环唑的光解,但促进三环唑的光解;河水中的颗粒物抑制目标农药的光解,但海水中的颗粒物却能促进目标农药的光解.总体而言,水环境中3种唑类农药的降解半衰期都较长,在实际水环境中的存在状况和毒理效应值得进一步研究.
The present study describes the abiotic degradation （photolysis and hydrolysis） and its influencing factors of three azole pesticides （tricyclazole,pyraclostrobin and difenoconazole） in river water and seawater under both natural and indoor controlled conditions. Results indicated the degradation of the 3 target pesticides in river water and sea water could be well fit to a first-order kinetic model. Under outdoor conditions at summer in Xiamen with mean temperature 25—32 ℃,abiotic degradation half-lives in river water were 17.6—49.8 d for tricyclazole,25.6—90.5 d for epoxiconazole,and 16.5—42.6 d for difenoconazole,and photolysis half-lives were 19.9—73.6 d for tricyclazole,28.0—131.8 d for epoxiconazole,17.6—50.5 d for difenoconazole,and hydrolysis half-lives were 154.0 d for tricyclazole,288.8 d for epoxiconazole and 271.8 d for difenoconazole. While in seawater the abiotic degradation half-lives were 22.8—48.1 d for tricyclazole,74.8—93.8 d for epoxiconazole,37.2—48.4 d for difenoconazole, the photolysis half-lives were 34.1—160.6 d for tricyclazole,113.4—163.8 d for epoxiconazole and 87.4—193.0 d for difenoconazole,and the hydrolysis half-lives were 68.6 d for tricyclazole,219.7 d for epoxiconazole and 64.6 d for difenoconazole. Photolysis played predominant roles in the abiotic degradation. Photolysis rates in river water were faster than those in seawater. In indoor controlled photolysis experiments,NO-3 inhibited the photolysis of the target compounds. Humic acids showed inhibitory effects on the photolysis of pyraclostrobin and difenoconazole while enhaced tricyclazole photolysis. Particulate matter inhibited photolysis of the 3 pesticides in river water while had positive effects on the degradation in seawater. In summary,tricyclazole,pyraclostrobin and difenoconazole are relatively persistent in the aquatic environment and their occurrence in natural waters and toxic effects deserve further study.
出处
《环境化学》
CAS
CSCD
北大核心
2014年第1期30-36,共7页
Environmental Chemistry
关键词
唑类农药
光解
水解
河水
海水
azoles, photolysis, hydrolysis, river water, seawater.
