重金属元素在贵州红枫湖水体中的分布特征

Distribation of heavy metal elements in the water body from Lake Hongfeng.

以贵州红枫湖为研究对象,分析了该湖13个采样点的上覆水、表层沉积物间隙水和表层沉积物中的Cd、Pb、Cu、Zn、Fe、Mn6种重金属的浓度.其中,上覆水和间隙水中的金属浓度呈现相同的分布趋势:Fe>Mn>Zn>Pb>Cu>Cd;而沉积物中的金属浓度略有不同,为Fe>Mn>Zn>Cu>Pb>Cd.同种重金属在三者间的分布顺序为:沉积物>间隙水>上覆水,表明该湖中的重金属有从沉积物向上覆水扩散的可能.相关性分析表明,上覆水、表层沉积物间隙水和沉积物中的金属浓度之间没有明显的相关性;通过主成分分析,对该湖水体重金属的来源及迁移趋势进行评估,其中沉积物中重金属提取出一个主成分(贡献率为67.7%),而间隙水和上覆水的分析中分别提取出2个主成分,其中间隙水贡献率为73.6%和16.73%,上覆水为44.2%和25.1%.红枫湖水体重金属元素含量相对国内湖泊偏高,其中北湖水体各金属元素含量普遍高于南湖水体.

Thirteen groups of samples（overlying water,pore-water and sediment） were collected from Hongfeng Lake,located on Yunnan-Guizhou Plateau in southwestern China,to study the behavior and fate of six heavy metals（Cd,Pb,Cu,Zn,Fe and Mn）.The results demonstrate that pollution levels of these metals in overlying water and pore-water share the same order：Fe〉Mn〉Zn〉Pb〉Cu〉Cd,while metal concentrations in the sediment is slightly different：Fe〉Mn Zn〉Cu〉Pb〉Cd.For a single element among these heavy metals,its concentration in sediment was highest,and then that in pore-water was higher than in overlying water.This phenomenon probably means that the heavy metals in the sediment of the lake may be released from the sediment into the overlying water.Although statistical analysis suggested that there was no significant correlation between the concentrations of these metals occurred in overlying water,pore-water and sediment,there are some correlations between these elements.To present a more insight analysis,principal component analysis was applied to study the pollution source of heavy metals concerned.It was found that only one component（representing 67.7% of total variance） was extracted for concentrations of these elements in sediments and two components for those in pore-water（representing 73.6% and 16.73% of total variance respectively） and overlying water（representing 44.2% and 25.1% of total variance respectively）.