堆敷灭螺法土壤中氯硝柳胺含量动态变化及其实验室灭螺效果

Change of niclosamide concentration in soil through heaping and the effect of Oncomelania control

目的分析堆敷灭螺法氯硝柳胺在土壤中的分布、随时间的变化趋势及其实验室灭螺效果,并探讨其合理的用药量。方法在四川省普格县特兹乡选择6个试验点,实施氯硝柳胺堆敷灭螺,施药剂量分别为16、8、4、2、1和0 g/m2。采集的土壤样品经超声萃取、离心、浓缩以后用高效液相色谱测定其含量;灭螺试验分别计算3 d、7 d钉螺死亡率。结果各施药组土壤中氯硝柳胺含量的标准差均较大,各组表层土与深层土氯硝柳胺的含量差异均无统计学意义(P>0.05);4 g/m2组施药后5个月土壤中还能检测到氯硝柳胺。随着土壤中氯硝柳胺含量的降低,施药后0个月、5个月各组表层、深层土壤样品的3 d、7 d钉螺死亡率也均呈下降的趋势(P<0.05);4 g/m2组施药后5个月仍有一定的灭螺效果,其表层土壤样品的3 d、7 d钉螺死亡率分别为5.33%、9.33%,高于对照组(P<0.05)。结论堆敷灭螺法是一种比较有效的灭螺方法,建议堆敷灭螺现场使用4 g/m2的剂量。

Objective To analyze the concentration,distribution and decreasing trend of niclosamide in soil through soil heaping mixed with niclosamide and the effect of Oncomelania control,and to explore the appropriate dosage for the ＇heaping＇ method. Methods The soil samples were collected from six groups in Tezi township,Puge county,Sichuan Province,and the dosages were 16,8,4,2,1 and 0 g/m^2,respectively.After ultrasonic extraction,centrifugence and concentration,the samples were finally determined by high-performance liquid chromatography（HPLC）.The mortality rate of snails was observed after 3 days and 7 days. Results The standard error and range of niclosamide in soil were large.There was no significant difference in concentration of niclosamide between the surface layer and deep layer of soil（P0.05）.After 5 months,niclosamide still could be determined in groups of 4 g/m^2.The mortality rate of snails decreased as the concentration of niclosamide decreased（P0.05）.After 5 months,in the group of 4 g/m2 dosage,the 3 and 7 days mortality rate of snails were 5.33% and 9.33% in the surface layer,higher than the control group（P0.05）. Conclusions The heaping method is an efficacious measure of controlling snails and its recommended dosage is 4 g/m^2.