水体酸化条件下Cu(II)对斑马鱼胚胎的毒性效应

为评价由酸雨、酸性矿山排水等环境污染导致的水体酸化及水体重金属联合作用对水生生物的生态毒性效应,研究了不同pH值(pH=3、4、5、6、7和7.8)条件下Cu2+对斑马鱼胚胎发育的影响。结果表明,酸性水体及Cu2+单一存在时,酸对斑马鱼胚胎24h半数效应浓度值EC50为pH=3.65,Cu2+(pH=7.8)对斑马鱼胚胎24h-EC50为0.267mg·L-1;当水体酸化及水体中的Cu2+共存时,较低的pH对Cu2+的生物毒性起协同作用,表现为随溶液pH的降低,各浓度Cu2+对斑马鱼胚胎的24h凝结率显著增高(P24h致死率=0.001),而斑马鱼胚胎96h孵化率显著降低(P96h孵化率=0.002),且不同浓度的Cu2+之间的生物毒性效应存在显著性差异(P24h致死率=0.0321;P96h孵化率=0.0028)。这说明酸性水体和Cu2+都显著影响斑马鱼胚胎的发育,且Cu2+在酸性水体中对斑马鱼胚胎的毒性显著增强。因此,在受重金属Cu2+污染的地区,如同时受到酸雨或酸性矿山排水等较低pH值和Cu2+的双重胁迫,较低浓度的Cu2+就能够对水生生物的生殖发育及水生生态系统产生严重的影响和危害。

Toxic Effect of Cu (Ⅱ) on Zebrafish Embryos under Water Acidification Condition

To assess ecotoxic effects of Cu²⁺ in acid solution caused by acid mine drainage and acid rain on aquatic organisms, zebrafish were used as test organism to study the effects of different concentrations of Cu²⁺ on zebrafish embryonic development under different pH (pH=3, 4, 5, 6, 7, 7.8). Under acid solution and Cu²⁺ stress independently, the values of 24 h-EC₅₀ for acidity and Cu²⁺ (pH=7.8) were pH=3.65 and 0.267 mg·L^-1, respectively. When the solutions were acid, the biotoxicity of Cu²⁺ to zebrafish increased. Specifically, with the decrease of pH, the condense ratio of embryos under different concentrations of Cu²⁺ increased significantly (P_{24 h}=0.001), and the incubation ratio after 96 h decreased significantly (P_{96 h} =0.002) and significant differences of biotoxicity existed among different concentrations of Cu²⁺ (P_{24 h} =0.0321; P_{96 h} =0.0028). It can indicate that both acid solution and Cu²⁺ can affect the development of embryos, and the toxicity of Cu²⁺ in acid solution to embryos increased significantly. Therefore, affected by acid rain or acid mine drainage and polluted by Cu²⁺, even when the concentration of Cu²⁺ is very low, the reproduction and development of aquatic organisms and aquatic ecosystem were seriously influenced.