百花湖麦西河口沉积物剖面重金属的形态分布

为揭示贵阳市百花湖入湖河口——麦西河口沉积物剖面中重金属的形态分布特征,采用柱状采泥器通过临水垂直插管法采集沉积物样品。借鉴改进Tessier五步连续提取法对沉积物中4种重金属Cd、Cu、Zn、Pb的形态在垂向上的分布进行测定,并对其总量进行讨论。结果表明:重金属总量由大到小的顺序为:Zn、Cu、Pb、Cd,含量分别为190.53～302.08、82.44～192.37、21.67～94.70、0.13～1.86mg/kg。其中,Cd主要以离子交换态、铁/锰氧化物结合态存在;Cu主要以有机质及硫化物结合态和残渣晶格结合态存在;Pb与Zn主要以有机质及硫化物结合态、铁/锰氧化物结合态和残渣晶格结合态存在。4种重金属的总量和形态在垂向上的分布因重金属种类不同而有所差异,呈现出垂向分布的不规律性。

The Morphology Distribution of Heavy Metals in the Section of Maixi Estuary Sediments in Baihua Lake

In order to reveal the morphology distribution characteristics of heavy metals in profile of Maixi estuary sediments of Baihua Lake in Guiyang City,a columnar sediment sampler through water vertical intubation was adopted to collect sediment samples.The vertical distribution of four heavy metals Cd,Cu,Zn and Pb in sediments were determined by using improved Tessier sequential extraction method.The results showed that the order of total content of heavy metals is Zn(190.53-302.08 mg/kg)>Cu(82.44-192.37 mg/kg) > Pb(21.67-94.7 mg/kg) > Cd(0.13-1.86 mg/kg).Among which,Cd existed as ion exchange state and Fe-Mn oxide form;Cu existed as organic sulfide combining form and residue lattice combining form;Pb and Zn existed as organic sulfide combining form,Fe/Mn oxide form and residue lattice combing form.The vertical distribution of total amount of four heavy metals and form varied with heavy metal species,indicating no regularity of vertical distribution.