铜在鲤鱼(Cyprinus carpio)鱼鳃微环境中的形态分布

Copper Speciation in the Gill Microenvironment of Cyprinus carpio

利用 Playle设计的装置测定了不同铜暴露水平下鲤鱼鳃部进出水中的游离铜离子浓度、粘液含量及有关参数 .用MINTEQA2和单配位体模型联合的试算方法计算了不同形态铜含量以及鳃部粘液对铜的络合能力 .结果表明 ,利用该算法可以获得鱼鳃微环境金属形态分布的准确结果 ,同时可以得到与鱼鳃粘液络合能力有关的参数 .随着暴露铜含量增加 ,粘液分泌量随之增加 ,鱼鳃微环境 p H和碱度也有所上升 .鱼鳃粘液的络合当量浓度 ( Cu/ C)和稳定常数 (对数 )分别为 0 .95mmol/ mg和5.32 .就铜形态分布而言 ,鱼鳃微环境与外部水相的主要差别表现在相对较高的羟基络合态铜含量以及占总量 3%～ 2 0 %的鱼鳃粘液络合态铜 .

Concentrations of free copper and mucus and other parameters including pH and alkalinity of the gill microenvironment of Cyprinus carpio exposed to copper of various levels were determined using Playle's apparatus.MINEQA2 was applied to calculate the copper speciation and singlesite complexation model was employed for characterizing the complexation capacity of gill mucus for copper.A procedure of trial and error with the two approaches involved was developed for the speciation calculation.It was shown that excretion of mucus was positively correlated to the total copper level in water.It was found that in the gill microenvironment,both pH and alkaline are higher than that in the bulk water,causing the difference in copper speciation.From 3 to 20% of copper in the microenvironment was mucus complexed.