不同水域鲤鱼耳石微化学特征及其环境指示意义

Microchemical characteristics of carp otoliths from two different water environments and their indication significance for environmental changes

利用中子活化分析对密云水库与白洋淀水域两个不同水域(无污染水域和重污染水域)中鲤鱼耳石的微量元素进行分析,发现白洋淀鲤鱼耳石中Sr、Zn、As、Au、Ba、K、Na的含量明显比密云水库鲤鱼耳石的相应元素含量高。采用线性判别方法对两地耳石中Sr、Zn、As、Ba4种元素进行分析,表明存在明显的分组差异,而且两地的差别主要在于Sr含量不同,其次是Zn、As和Ba;白洋淀鲤鱼耳石中As、Ba、Sr、Na等元素含量变化幅度比密云水库鲤鱼耳石中相应元素含量的变化幅度大,与白洋淀水域废水排放时间上的周期性和短暂性导致元素在耳石部分日轮上沉淀等因素相吻合。两地鲤鱼耳石微量元素特征存在截然的区别,与两地水域水体中微量元素差异相一致,表明鲤鱼耳石微化学特征具有水化学环境指示意义,为进一步研究利用鲤鱼耳石进行水化学环境监测或恢复鲤鱼生长期水环境特征奠定了基础。

Asteriscus otoliths of carps were collected from the Baiyangdian shallow lake and the Miyun reservoir, whose water environments are completely different. The former has been seriously polluted whereas the latter is nearly pure and has experienced no pollution. The otoliths were analyzed by Neutron Activation Analysis （NAA） for microchemical characteristics as indicators to hydrochemical changes. The contents of Sr, Zn, As, Au, Ba, K and Na in the otolith from the Baiyangdian shallow lake are obviously higher than those from the Miyun reservoir. Linear Discriminant Function Analysis （STATISTICA） was uses to classify carp collection sites. The discriminant functions show the major differences between the two sites are the differences in concentrations of Sr, Zn, As and Ba. Moreover, the variation ranges of As, Ba, Sr and Na in otolith from the Baiyangdian shallow lake are relatively larger than those from the Miyun reservoir, which is in accord with the fact that a sea,hal and temporal influx of industrial waste into the Baiyangdian shallow lake drainage area causes the precipitation of these elements in some otolith growth increments. The differences of these elements in otoliths from these two areas are consistent with those in the carp living water. These conclusions are of significance in studying indicators to hydrochemical environments.