非离子氨氮和亚硝酸盐氮对暗纹东方鲀稚鱼的急性毒性试验

Acute Toxicity of Non-ionized Ammonia and Nitrite to Postlarva Puffer Takifugu fasciatus

在水温21~23℃,pH 8.2~8.5,溶解氧6.00~7.50mg/L的条件下,采用半静水法研究了非离子氨氮和亚硝酸盐氮对全长（1.6±0.2）cm、体质量为（0.11±0.05）g的暗纹东方鲀稚鱼的急性毒性效应。试验结果表明,暗纹东方鲀稚鱼受到非离子氨氮和亚硝酸盐氮胁迫后,先后出现鱼体体色变白、扭曲、侧游、失去平衡、昏迷等中毒症状。随着非离子氨氮和亚硝酸盐氮质量浓度的提高和胁迫时间的延长,暗纹东方鲀稚鱼死亡率逐渐升高,存在明显的剂量效应和时间效应关系。非离子氨氮和亚硝酸盐氮对暗纹东方鲀稚鱼96h半致死质量浓度分别为0.46mg/L（95%置信限0.34~0.64mg/L）和290.12mg/L（95%置信限255.16~329.87mg/L）,安全质量浓度分别为0.046 mg/L和29.01mg/L。非离子氨氮和亚硝酸盐氮对暗纹东方鲀稚鱼具有一定毒性,且非离子氨氮毒性大于亚硝酸盐氮毒性。

The acute toxicity of non-ionized ammonia and nitrite to postlarvae of puffer Takifugu fasciatus with total length of（1.6 ± 0.2）cm and wet body weight of（0.11 ± 0.05）g was studied by 96 hsemistatic bioassays under conditions of water temperature 21—23℃,pH 8.0—8.5and dissolved oxygen level of 6.00—7.50 mg/L.The postlarvae exposed to the non-ionized ammonia and nitrite showed a series of poisoning symptoms,such as body whitening and bending,and loss of equilibrium and had elevated mortality gradually with increase in the toxicant concentration and exposure elapse,with dose-time dependent.The 96 h median lethal concentration（96hLC50）values of the postlarvae was found to be 0.46 mg/L（95% confidence limits：0.34—0.64mg/L）with safe concentration（SC）values of 0.046mg/L for non-ionized ammonia and 290.12mg/L（95%confidence limits：255.16—329.87mg/L）with SC of 29.01mg/L for nitrite.The findings demonstrated that both non-ionized ammonia and nitrite were toxic to the puffer and that non-ionized ammonia had stronger toxicity than nitrite.