Effects on the population dynamics of Brachionus rubens(Rotifera)caused by mercury and cadmium administered through medium and algal food Chlorella vulgaris  

在培养基和食料中添加铅和镉对轮虫种群动态的影响

作　　者：S.S.S.SARMA Hilda Fabiola NUÑEZ-CRUZ S.NANDINI S.S.S.SARMA;Hilda Fabiola NUÑEZ-CRUZ;S.NANDINI(Laboratory of Aquatic Zoology,Division of Investigation&Postgraduate Studies Building UMF,National Autonomous University of Mexico,Campus Iztacala,AP 314,CP 54090,Tlalnepantla;UIICSE,Division of Investigation&Postgraduate Studies,National Autonomous University of Mexico,Campus Iztacala,AP 314,CP 54090 Tlalnepantla,State of Mexico,Mexico)

机构地区：[1]Laboratory of Aquatic Zoology,Division of Investigation&Postgraduate Studies Building UMF,National Autonomous University of Mexico,Campus Iztacala,AP 314,CP 54090,Tlalnepantla [2]UIICSE,Division of Investigation&Postgraduate Studies,National Autonomous University of Mexico,Campus Iztacala,AP 314,CP 54090 Tlalnepantla,State of Mexico,Mexico

出　　处：《动物学报》2005年第1期46-52,共7页ACTA ZOOLOGICA SINICA

基　　金：This research was funded by a grant from PAPIIT—IN204101.SSSS and SN also thank National System of Investigators(SNI一18723&20520)

摘　　要：Due to industrial activities,heavy metal concentrations in aquatic systems of Mexico,are on the rise.Zooplankton,particularly rotifers,being sensitive and common components of freshwater,are widely used in ecotoxicological tests for establishing water quality criteria.Depending on the route of exposure(i.e.via medium or algal food),the toxicity of heavy metals varies.In the present study we evaluated the effect of cadmium and mercury exposed through medium and via algal food for the rotifer B.rubens.For both the heavy metals,we exposed rotifers via medium containing Chlorella at 0.5×10^(6)cells/ml or fed daily on previously exposed(1,2 and 4 h)alga to the toxicants(using 5 times the value of LC_(50)for B.rubens).For cadmium toxicity through medium,we used 3 toxicant levels(0.1,0.2 and 0.4 mg/L)and for mercury,we used 0.005,0.010 and 0.015 mg/L.Based on the LC_(50),B.rubens was 24 times more sensitive to mercury(0.035±0.002 mg/L)than cadmium.At a concentration of 0.4 mg/L,cadmium through the medium caused increased lag phase of B.rubens.When grown on Chlorella exposed for different durations to cadmium,the rotifer density decreased with the increasing duration of algal exposure to the heavy metal.When mercury was used in the medium or via algal food,the trends in the population growth of B.rubens were similar to those for cadmium.An increase in heavy metal concentration in the medium resulted in a decrease of the rate of population increase per day(r).The r varied from 0.33(in control)to 0.02 d^(-1)(in heavy metal treatment)depending on the mode of exposure though medium or via algal food.由于工业活动的影响,墨西哥水体环境中的重金属浓度在上升。浮游动物,尤其是轮虫类,由于对环境变化十分敏感而且是淡水中的常见组成部分,因此被广泛用于生态毒理试验以确定水质标准。在不同的胁迫途径下(如通过培养基或食料),重金属的毒性是不同的。在本研究中,通过在轮虫Brachionusrubens的培养基和食料中添加重金属这两种途径,我们评估了镉和铅的效应。对于这两种重金属,均采用将轮虫置于含05×10^(6)个/ml绿藻的培养基中或每天喂食经5倍于LC_(50)值的金属处理(1,2和4h)的绿藻。对于在培养基中添加镉,使用了三个毒性水平(01,02和04mg/L),铅的浓度分别为0005,0010和0015mg/L。基于LC_(50)的数据,B.rubens对铅的敏感性要比镉高24倍。镉浓度为04mg/L时,培养基中加入镉造成B.rubens的生长趋缓。而喂食经不同时间处理的绿藻后,轮虫的密度随着食料在重金属中处理时间的延长而减小。培养基中或食料中添加铅时,轮虫种群生长的的趋势与在镉处理下的情况类似。随着培养基中重金属浓度的增加,每天种群增长率(r值)会减小。在培养基和食料处理两种不同途径下,r值会在033(对照)到002d^(-1)(经重金属处理)

关 键 词：ROTIFERA Brachionus rubens Heavy metal toxicity Population growth Chronic toxicity Acute toxicity 

分 类 号：X174[环境科学与工程—环境科学]