不同浓度下四种除草剂对福寿螺和坑螺的生态毒理效应

以化学除草剂应用为前提的水稻免耕抛秧栽培技术是近年来推广的节本栽培新技术。为更好地评价除草剂的环境风险,为防治除草剂的负效应提供科学依据,采用室内静水模拟实验研究了4种免耕稻田除草剂丁草胺、苄嘧磺隆、丁苄混剂和氯酸钾的3种浓度梯度下对典型水生动物福寿螺、坑螺的影响。结果表明,各除草剂对水生动物的代谢都有不同程度的影响, 氯酸钾和苄嘧磺隆对2种水生动物的呼吸作用影响不大,而丁草胺和丁苄混剂对3种水生动物的呼吸作用的影响有显著的抑制作用,且呈现一定的剂量效应;在本实验染毒剂量下, 丁草胺和丁苄混剂对2种水生动物的存活率影响很大,而氯酸钾和苄嘧磺隆对其存活率影响较小。丁草胺和丁苄混剂处理对福寿螺的氮代谢影响远远大于氯酸钾和苄嘧磺隆处理,而从水体总氮和总磷含量的影响来看,4种除草剂对其影响都较大。总之,从4种除草剂对实验用螺存活率和主要代谢生理指标的综合影响大小来看,丁草胺>丁苄混剂>苄嘧磺隆>氯酸钾。

Eco-toxicological effects of four herbicides on typical aquatic snail Pomacea canaliculata and Crown conchs

There has been an increase in the use of other herbicides for both agricultural and non-agricultural purposes. The use of herbicides in China also has increased faster than that of insecticides and fungicides since last 30 years. The new technique of rice seedling-broadcasting with no-tillage (RSB-NT) is widely used and it was based on the applition of herbicides. The increasing pollution of herbicides in soil and water has been of concerns. The effect of four herbicides including butachlor, bensulfuron-methyl, the mixture of bensulfuron and butachlor, potassium chlorate on typical aquatic animals (Pomacea canaliculata Spix, Tunnel snail) in rice paddy wetland were studied in laboratory. In the immersion experiment, both of the aquatic animals divided into four groups with three concentrations. The results showed that the metabolism of them was affected by these herbicides. The respirations of those two aquatic animals were little affected by potassium chlorate and bensulfuron-methyl, but the respirations of them were significantly inhibited by butachlor and the mixture of bensulfuron and butachlor. Butachlor and the mixture of bensulfuron and butachlor have more infection than potassium chlorate and bensulfuron-methyl to the livability of them. The results also indicated that the NH₄-N, phosphor, and total nitrogen in water with the aquatic animals were affected by these herbicides. Butachlor and the mixture of bensulfuron and butachlor have more influence on excretion rate and phosphor excretion rate of Pomacea canaliculata and Tunnel snail were significantly affected by these four herbicides. In conclusion, the results demonstrated that the best choice for herbicides in rice paddy was the mix of bensulfuron and butachlor, the second was bensulfuron-methyl, the third was butachlor and the last was potassium chlorate according to the impacts of herbicides to the typical aquatic organisms in rice wetland.