低pH和铝对几种淡水鱼类早期生活阶段的影响

在实验室条件下,把早期生活阶段的白链(Hyhophthalmichthys molitrix)、鳙鱼(Arist-ichthys nobilis)和草鱼(Ctenopharyngodon idellus)突然置于一系列低pH值水中,以测试产生毒性影响的pH水平.在受试的三种鱼中,未发现对低pH的敏感性有显著差异,但在发育过程中其敏感性逐渐降低.在pH5.0的水中,Al(0.1—16mg/L)对草鱼仔鱼毒性测试结果表明,96h的LC_(50)为0.26mg/L(0.21—0.31mg/L),致死阈浓度为0.1mg/L.

TOXIC EFFECTS OF LOW pH AND ELEVATED Al CONCENTRATION ON EARLY LIFE STAGES OF SEVERAL SPECIES OF FRESHWATER FISHES

Silver carp (Hypophthalmichthys molitrix), bighead Carp (Aristichthys nobilis) and grass carp (Ctenopharyngodon idellus) were abruptly exposed to a range of low pH under laboratory conditions to determine effect levels of pH at early life stages, Mortality, hatching, development and deformation were monitored. No significant differences in sensitivity were observed among the three species, while sensitivity to low pH levels decreased with increasing age. Eggs showed delayed hatching below pH 6.5, increased mortality and deformation rate at pH 6.0 or lower. A significant decrease occurred below pH 5.5 in fries survival and below pH 4.6 in Juveniles, compared with control at pH 8.0. Acutely toxic effects of dissolved Al were studied in fries of grass carp exposed to concentrations of 0.1-16mg Al/L at pH 5.0. Results showed the LC50 value to be 0.28mg/L (0.21-0.31mg/L),with a lethal threshold concentration of 0.1mg/L.