泉州湾洛阳江河口桐花树和秋茄红树植物中重金属元素的分布与富集特征

Distribution and Enrichment of Heavy Metals in the Mangrove Plants of Aegiceras Corniculatum and Kandelia Candel Collected from Luoyang Estuary in Quanzhou Bay

通过测定泉州湾洛阳江河口红树林区表层沉积物中酸提重金属元素含量及桐花树、秋茄两种红树植物各部位中重金属元素含量,分析了重金属元素在两红树植物不同部位的分布特征及其富集和迁移能力,并初步探讨了两种红树植物体内各重金属元素的主要来源。红树林区各采样点表层沉积物中重金属元素酸提量顺序为:Fe>Mn>Zn>Pb>Cu>Cr>N i>Co,Cu和Pb的平均酸提量超过第一类海洋沉积物质量标准限值。同种元素在两种红树植物不同部位中的含量顺序一致:Cu为根>枝>叶;N i为叶>根>枝;Fe、Mn、Cr、Zn、Pb、Co为根>叶>枝。两种红树植物对N i、Cr、Cu、Zn、Fe、Mn的富集能力高于Co和Pb。秋茄对Cu、N i、Mn、Fe、Co的富集能力比桐花树略强些,而对Zn、Cr、Pb的富集能力则相对弱些;但两种植物对各元素的富集能力都达不到超富集植物的要求。两种植物对N i元素的富集能力都大于其他元素,且都集中在叶部,其他元素则主要集中在根部。除N i外,其余元素在两植物体内的迁移系数均小于1。桐花树中的Cr和秋茄中的Cu、Zn、Mn主要来源于林地沉积物,其他元素在两植物各部位均有不同的来源。

The distribution,enrichment and migration characteristics of heavy metals in the mangroves of Aegiceras corniculatum and Kandelia candel were studied by means of determining the contents of acid extractable heavy metals in surface sediments and in different parts of each mangrove collected from the mangrove swamp in Luoyang estuary of Quanzhou Bay.The main sources of heavy metals in the investigated mangroves were also discussed preliminarily in this article.The contents of heavy metals in the surface sediments showed a sequence of FeMnZnPbCuCrNiCo,in which the average contents of Cu and Pb were higher than the quality standard limit（level Ⅰ） for marine sediments.The contents of heavy metals in different parts of both mangroves were in the accordant order of rootbranchleaf for Cu,leafrootbranch for Ni and rootleafbranch for Fe,Mn,Cr,Zn,Pb and Co.The enrichment capability for Ni,Cr,Cu,Zn,Fe and Mn in both mangroves was higher than that for Co and Pb.The enrichment capacity of Kandelia candel for Cu,Ni,Mn,Fe and Co was higher than that of Aegiceras corniculatum,while relatively lower for Zn,Cr and Pb.But the two kinds of the plants can not come up to the requirements of hyper-accumulators according to their accumulation capacity for each element.For both plants,the enrichment capability for Ni was the highest,which concentrated mainly in leaves.While the other elements mainly concentrated in roots.Except for Ni,the migration factors of all other elements in both plants were lower than 1.The content of Cr in Aegiceras corniculatum and Cu,Zn and Mn in Kandelia candel were mainly derived from the mangrove sediments,and there were different sources for other elements that accumulated in different parts of two plants.