不同重金属混合液对萼花臂尾轮虫(Brachionus calyciflorus)实验种群增长的影响

摘要

为探究重金属复合污染对轮虫种群增长的影响,以萼花臂尾轮虫(Brachionus calyciflorus)为受试生物,采用析因设计方法设置ρ(Cu2+)为0.001和0.01 mg·L-1、ρ(Zn2+)为0.01和0.1 mg·L-1、ρ(Cd2+)为0.01和0.1mg·L-1、ρ(Cr6+)为0.01和0.1 mg.L-1和ρ(Mn2+)为0.1和1 mg.L-1不同组合的混合液,利用轮虫群体累积培养方法,研究暴露于不同重金属混合液中的轮虫18d实验种群增长的变化情况,探讨不同处理组对轮虫种群增长率和轮虫最大种群密度的影响.结果显示,重金属混合液组成成分浓度的变化显著影响其对轮虫的毒性,高浓度重金属混合液均显著降低轮虫种群增长率和轮虫最大种群密度.每种重金属离子和其他4种重金属混合液浓度的交互作用均显著影响轮虫种群增长率;Zn2+和其他4种重金属混合液浓度的交互作用显著影响轮虫最大种群密度.轮虫种群增长率对重金属混合物中各组成成分之间的交互作用更加敏感,适合用来监测重金属复合污染对轮虫种群的长期、慢性毒性影响.%To explore effects of combined heavy metal pollution on aquatic organisms,an experiment was carried out using fresh water rotifers,Brachionus calyciflorus,which are among the most important groups of zooplankton in terms of biomass,ecological importance and bio-diversity,and are recognized as ideal bioassay animals for toxicity tests because of their small size,short generation time and rapid reproduction rate.However,few reports are available in the literature on impacts of combined heavy metal pollution on rotifers.This experiment was designed to use solutions of heavy metal mixture,containing Cu2+(0.001 and 0.01 mg · L-1),Zn2+(0.01 and 0.1 mg · L-1),Cd2+(0.01 and 0.1 mg · L-1),Cr6+ (0.01 and 0.1 mg · L-1),Mn2+(0.1 and 1 mg · L-1) and 18 d old freshwater rotifers in the cumulative culture test.Population growth rate and maximal population density of the rotifers were monitored.Results show that concentrations of the metals in the solution was the major factor affecting toxicity of the solution to the rotifers.Population growth rate and maximal population density of the rotifers were significantly lowered by solutions high in heavy metal concentration.Interactions of any given element with the other 4 in concentration in the solution all significantly influenced population growth rate of the rotifers,while interactions of Zn2+ with the other 4 in concentration in the solution significantly influenced maximal population density of the rotifers.The rotifers were more sensitive to interactions between the elements in the solution in population growth rate than in maximal population density.So they can be used as bio-indicator to monitor combined heavy metals pollution of water bodies.