毒死蜱对我国南方稻区水域中12种淡水鱼的毒性

毒死蜱作为稻田常用农药,普遍存在于稻区沟渠、池塘和河流中,从而对生活在其中的鱼类具有潜在风险。通过短期暴露试验,比较了毒死蜱在纯水、水-沉积物体系中对淡水鱼的毒性效应,进一步研究了毒死蜱在不同鱼体内的生物富集作用,以及对鱼脑Ach E活性的影响。试验结果表明:毒死蜱对12种淡水鱼均表现为高毒或剧毒,最敏感的是太阳鱼,但体系中沉积物的存在会通过吸附作用降低农药对鱼类的毒性;毒死蜱在鱼体内表现为中等或高富集性,其中斑马鱼的富集系数最大;毒死蜱对鱼脑Ach E酶活性有明显抑制作用,其中以虹鳟最敏感。研究结果为稻田常用农药对水生态环境中鱼类安全的风险性评价提供了科学依据。

Toxic Effects of Chlorpyrifos on Different Species of Freshwater Fish in Southern China

Chlorpyrifos, a commonly used insecticide, is widespread in the paddy field, ditch, pond and river, and accordingly, it poses a potential risk to fish in the aquatic environment. Using short term exposure measurement, the toxicity of chlorpyrifos to freshwater fish in the aquatic ecosystem and water-sediment system was examined, with the further investigation of bioaccumulation of chlorpyrifos in different fish species and influence of chlorpyrifos on activity of AchE in fish-brain. As a result, it showed that chlorpyrifos was high toxic or hypertoxic to 12 species of freshwater fishes, of which Lepomisgibbosus was identified as the most sensitive species, despite that adsorption of pesticides by environmental sediments decreased their toxicities to fishes. In addition, enrichment of chlorpyrifos in fishes was shown in a moderate or high level, and moreover, bioconcentration factor was calculated highest in Daniorerio. Inhibitory effect of chlorpyrifos on brain AchE activity was also remarkable and Oncorhynchusmykiss was identified as the most sensitive species. Taken together, the data presented in this work provide scientific basis for the risk assessment of the pesticides commonly used in the paddy field to the fishes in the aquatic ecosystem.