4 种重金属离子对中华鳖(Trionyx sinensis)稚鳖的急性致毒效应

以5日龄中华鳖稚鳖为实验动物,采用静水停食实验法,在水温(27.4±1.3)℃条件下,开展了Hg2+、Cr6+、Cu2+、Zn2+对中华鳖稚鳖的急性毒性和加和等毒性强度联合毒性试验。结果表明,4种重金属离子对中华鳖稚鳖均呈现以蓄积为主导的急性毒发效应,Cr6+、Zn2+对中华鳖稚鳖的急性致毒高峰期明显滞后于Hg2+、Cu2+;4种重金属离子毒性大小依次为Hg2+、Cu2+、Cr6+、Zn2+,其对中华鳖稚鳖96h的半致死质量浓度分别为5.98、16.42、28.90和91.88mg/L;所构建的中华鳖稚鳖累积死亡概率与重金属质量浓度和实验时间之间的数学模型,以及半致死时间-质量浓度回归方程,可作为侦查和分析重金属离子排放时间和致中华鳖稚鳖大量死亡时间的重要计算工具;Hg2+、Cr6+、Cu2+、Zn2+离子两两组合在加和等毒性强度下对中华鳖稚鳖96h联合急性毒性所呈现的致毒特征与离子种类及其毒性强度匹配情形密切相关。

ACUTE TOXIC EFFECTS OF FOUR HEAVY METALS ON TRIONYX SINENSIS JUVENILES

Acute toxicity of Hg~(2+), Cr~(6+), Cu~(2+), and Zn~(2+) and their joint toxicity on 5-day-old Trionyx sinensis juveniles in water temperature at (27.4±1.3)℃ were studied. Accumulative nature was revealed. The degree of toxicity was in the order of Hg~(2+)>Cu~(2+)>Cr~(6+)>Zn~(2+) as the mortality occurred, from early to late; and the median lethal concentrations (IC_(50)) at 96h were 5.98, 16.42, 28.90, and 91.88mg/L. The joint toxicity of the four heavy metal ions at 96h was closely related to ion species and toxicity intensity. Mathematical model and regression equation were built on the death cumulative prob-ability, the concentration of heavy metal ions, the massive death occurrence time, etc., and are important tools for detecting and forecasting the toxicity and mass mortality.