酵母提取物对大型蚤急性毒性实验的影响

Impact of yeast extract on acute toxicity test using Daphnia magna

为了缩短大型蚤急性毒性实验的周期,并且验证毒性实验的灵敏度和稳定性,对投加酵母提取物饲养的大型蚤的生长周期、2次产卵时间间隔、产卵数量、以及幼蚤灵敏度和稳定性进行研究,并将其应用于已知毒性物质和环境样品的毒性检测。结果表明,酵母提取物的适宜投加量为18.00~22.00 mg/L。在该浓度下饲养的大型蚤可保持较好的怀卵量,生长至成熟期和2次怀卵的时间间隔较短,幼蚤的灵敏度较好,毒性测试结果稳定。采用此方法测定的4种重金属和4种有机物的大型蚤急性毒性的24 h-EC50和48 h-LC50与已发表的实验结果比较相近,证明该方法准确、可靠。将该方法应用于城市生活污水急性毒性的测定发现,投加酵母提取物饲养的大型蚤所产幼蚤可以明显区分生活污水原水和处理后最终出水。因此,采用投加适量酵母提取物饲养大型蚤的方法可以缩短实验周期,为测定环境样品生物毒性提供方便。

To shorten the cycle of the acute toxicity test using Daphnia magna,the growth cycle,spawning interval,propagation ability of mature D. magna as well as the sensitivity and stability of Daphnia neonates were studied after yeast extract was added during the culture process. The acute toxicity test using the D. magna neonates was further optimized and applied on the known toxicants and environmental samples. The results show that the appropriate concentration of yeast extract is 18. 00 ~ 22. 00 mg / L on the account of good propagation ability,short growth cycle and spawning interval of mature D. magna,high sensitivity and stability. The acute toxicity of 4heavy metals and 4 organic compounds using this method is close to the already published results in terms of 24h-EC50 and 48 h-LC50,indicating that the developed method is accurate and reliable. This method was also applied to domestic wastewater,suggesting that D. magna could distrint raw water and secondary effluent. Hence,the method that appropriate yeast extract is used to culture D. magna could shorten the experimental time,which could provide a convenient method for detecting the biological toxicity of environmental samples.