溴氰菊酯茶园残留与使用安全性

Security Analysis of Residual Deltamethrin in Tea Plantation

为了探讨溴氰菊酯在绿茶和乌龙茶品种上的残留及其消解动态的差异,明确其在福建茶区使用的安全性,在福安、安溪和武夷山进行了福云6号、金观音、铁观音和水仙等4个不同品种茶树上溴氰菊酯残留田间试验,用2.5%溴氰菊酯乳油500～3 000倍液进行施药,药液干后1h以及1、3、5、7、10、15d分别取样制样供检测。检测统计结果表明,溴氰菊酯在茶叶上的残留量随着农药稀释倍数的增加而线性减少;相同浓度处理下,春茶的残留量一般高于夏茶和秋茶,而乌龙茶(金观音)品种高于绿茶(福云6号)品种。残留半衰期总体上表现为随着使用浓度提高而延长的特点,但各浓度处理间差异不显著;在相同气候条件下,相同浓度处理福安乌龙茶的残留半衰期比福安绿茶长,其中春季的差异达显著水平;各地同一茶季同一浓度条件下乌龙茶品种间的残留半衰期也不一致,差异达极显著水平。2.5%溴氰菊酯乳油500～3 000倍液在茶园的使用相对安全,目前GB/T 8321.1-2000农药合理使用准则(一)要求的安全间隔期(5d)的要求是合适的,但无公害茶叶生产基地和出口欧盟的基地如果使用2.5%溴氰菊酯乳油500～1 000倍液建议安全间隔期定为7d。

To investigate the final residues and dynamic degradation of deltamethrin sprayed on Fuyun 6, Jinguanyin, Tieguanyin and Shuixian （Camellia sinensis）, a security analysis of residual deltamethrin in different tea plantation （Fu＇an, Anxi and Wuyishan） was carried out after 500--3 000 times of 2.5% deltamethrin was air-dried or 1, 3, 5, 7, 10, 15 days after spraying. The results showed that the reduce residues has a linear relation with diluted times of the pesticides. On the one hand, the residual amounts treated with the same concentrations were higher in spring tea than those of summer tea or autumn tea, and more residual contents would be found in green tea varieties （Fuyun 6） than those of oolong tea varieties （Jinguanyin）. The half-life of the degradation was prolonged with the increased concentrations but with no significant differences. On the other hand, oolong teas had a long half-life of the degradation than those of green teas at the same concentrations, which respectively reached a significant level in spring. And there were significant difference of halblife among oolong tea varieties in every season sprayed with the same concentration of pesticides in each region. The usages of 500--3 000 times of 2.5% deltamethrin in the tea garden were relative safety concentrations. The status quo requirement of 5 days as the safety interval was appropriate according to the proposal of GB/T 8321.1-2000, Guideline for safety application of pesticides （ I ）, but 7 days was recommended for non-polluted tea garden and export base to the European Union member countries.