铜和镉对珠江天然仔鱼和幼鱼的毒性效应及其潜在生态风险

Toxicities and Potential Ecological Effects of Copper and Cadmium to Natural Fish Larvae and Juveniles from the Pearl River

以静水实验法探讨珠江流域主要金属污染物铜和镉对当地天然仔鱼和幼鱼的急性毒性效应。结果显示,铜对西江赤眼鳟和鲴仔鱼(48 h)和广东鲂幼鱼(96 h)的LC50分别为0.066、0.055和0.10 mg·L-1,对应的安全浓度分别为0.006、0.010和0.010 mg·L-1;镉对赤眼鳟和鲴仔鱼(48 h)以及广东鲂幼鱼(96 h)的LC50分别为1.29、0.83和3.20 mg·L-1,对应的安全浓度分别为0.163、0.077和0.320 mg·L-1。其中,铜对上述受试鱼的安全浓度低于或接近我国《渔业水质标准》及《地表水环境质量标准》Ⅱ类水对铜的规定,而镉对这些受试鱼的安全浓度则高于相关标准对镉的规定。研究结果表明,珠江流域铜污染可能会对当地天然仔鱼、幼鱼群体的补充构成一定程度的威胁,但镉污染暂不会对该区域主要鱼类早期群体补充带来严重的生态风险。

Acute toxicities were studied by static test of copper and cadmium to natural fish larvae and juveniles from the Pearl River The results show that the 48 h LC50 of Cu to larvae of Spualiobarbus curriculus and Xenocypris sp. and the 96 h LC50 of Cu to juvenile Megalobrama terminalis are 0.066, 0.055 and 0.10 mg. L 1, respectively, and the corresponding safety concentration thresholds are 0.006, 0.010 and 0.010 mg. L 1, re- spectively. The 48 h LC50 of Cd to larvae ofS. curriculus and Xenocypris sp. and the 96 h LCs0 of Cd to juven- ile M. terminalis are 129, 0.83, 32.0 mg·L-1, respectively, and the corresponding safety concentration thresh- olds are 0.163, 0.077 and 0.320 mg· L-1, respectively. Accordingly, concentration thresholds of Cu are equal to or lower than the limit value for Cu of the Water Quality Standard for Fisheries and the Class I1 level of Envi- ronmental Quality Standards for Surface Water for Cu, and the safety concentration of Cd is higher than the limit value for Cd of the above relative standards. This study suggests that Cu contamination in the Pearl Riv- er may affect the residential fish population.