铜、镉对水螅的急性和联合毒性作用

Toxicity and toxic effects of heavy metals cadmium and copper on Hydra sp.

试验研究重金属铜(Cu2+)、镉(Cd2+)对水螅的急性毒性和联合毒性作用,探索水螅(Hydra sp.)对Cu2+、Cd2+以及两者混合的毒性效应,为水产动物病害的防治中合理使用消毒、杀虫剂以及水体污染评价提供一些参考信息。结果表明,Cu2+对水螅的24 h半致死浓度(LC50)、48 hLC50、72 hLC50、96 hLC50分别为0.072、0.054、0.042、0.037 mg/L;Cd2+对水螅的24 hLC50、48hLC50、72 hLC50、96 hLC50分别为0.001 70、0.000 63、0.000 36、0.000 36 mg/L;Cu2+、Cd2+对水螅的安全浓度分别为3.7×10-4、3.6×10-6mg/L。水螅对两种重金属的毒性反应既快速又敏感,其中Cu2+对水螅的毒性较Cd2+快,但Cd2+的毒性比Cu2+的强。等毒性配比的两种重金属混合液对水螅的毒性大于单一毒性,为协同作用。两种重金属对水螅的LC50随试验时间的延长而减小,它们对水螅的安全浓度远低于渔业水质标准。

Acute toxicity and toxic effects of heavy metals cadmium （Cd^2＋ ） and copper （Cu^2＋ ）, alone and in combination, on Hydra sp. were investigated. The half lethal concentration （LC50） of Cu^2＋ on Hydra sp. exhibited in 24, 48, 72 and 96 h were 0. 072, 0. 054, 0. 042, and 0. 037 mg/L, respectively; the corresponding values for Cd^2＋ were 0. 001 70, 0. 000 63, 0. 000 36, and 0. 000 36 mg/L, respectively. Cu^2＋ below 3.7× 10^-4mg/L and Cd^2＋ below 3.6 × 10^-6mg/L were non-toxic. Although Cu^2＋ was slightly less toxic than Cd^2＋ , it produced faster toxic effects; they were more toxic to Hydra sp. than to many other aquatic animal and plant species. The joint toxicity of Cu^2＋ and Cd^2＋ on Hydra sp. was greater than predicted from the individual toxicities as a result of the synergetic effect.