pH对鲤鳃部微环境铜形态的影响

INFLUENCE OF Ph ONCOPPER SPECIATION IN THE GILL MICRO-ENVIRONMENT OF CYPRINUS CARPIO

利用Ｐｌａｙｌｅ等设计的装置研究了不同ｐＨ条件及不同的铜暴露水平下鲤鳃部微环境ｐＨ值和粘液分泌量的变化，在此基础上用化学平衡计算方法探讨鱼鳃微环境中铜形态的变化。结果表明，在特定的ｐＨ和铜浓度范围内，鱼鳃微环境平衡ｐＨ略低于７，鱼鳃粘液分泌量随铜暴露水平提高而增加，与此同时，虽然ＣＯ２分泌量有所增加，没有观察到微环境ｐＨ随铜暴露量的变化。ｐＨ的升高，导致水相优势的游离态铜让位给羟基络合铜，粘液络合态铜的分额逐渐降低，但不会改变其络合当量与条件稳定络合常数。由于鱼鳃微环境对ｐＨ改变的调节作用，铜的形态分布变化幅度低于外部环境。

Concentrations of free copper and other parameters including pH, alkalinity, IC, and TOC in the gill micro - environment of Cyprinus carpio exposed to copper of various levels under various pH conditions were measured by using Playle' s apparatus. MINTEQA2 was applied to calculate the copper speciation. Single - site complexation model was employed for characterizing the complexation capacity of the gill mucus for copper. The copper speciation in both bulk solution and the gill micro - environment was discussed.