哈尔滨市不同类型人工林枯枝落叶层重金属质量分数特征

Heavy Metal Concentration in Litter Layer of Different Types of Plantations in Harbin

以东北林业大学城市林业示范研究基地9种人工林(兴安落叶松林、樟子松林、黑皮油松林、黄波椤林、胡桃楸林、水曲柳林、白桦林、蒙古栎林和针阔混交人工林)为研究对象,分析了林地枯枝落叶层6种重金属(As、Cd、Cu、Ni、Pb、Zn)的质量分数,并以哈尔滨市土壤背景值为标准,采用综合污染指数法评价了不同林型枯枝落叶层重金属污染状况:不同类型人工林枯枝落叶层重金属质量分数差异显著或极显著。不同类型人工林重金属质量分数,以Zn最高,其值为96.09～224.21 mg.kg-1;Cd最低,为0.30～0.80 mg.kg-1。6种重金属质量分数排序为:Zn>Pb>Cu(Ni)>Ni(Cu)>As>Cd。重金属污染程度为:Cd>Pb=Zn>Cu>Ni>As。人工林枯枝落叶层Pb、Cd、Cu、Zn的质量分数高于背景值,为人为输入;Ni和As的质量分数与本地背景值相当,可归结为自然因素。不同林型内梅罗综合污染指数排序依次为:白桦林>黄波椤林>兴安落叶松林>胡桃楸林>樟子松林>针阔混交林>蒙古栎林>水曲柳林>黑皮油松林。

The aim of the present study was to investigate heavy metal contamination in litter layer of different urban plantations.Litter samples were collected from eight mono-cultured plantations（Larix gmelinii,Pinus sylvestris var.mongolica,Pinus tabulaeformis var.mukdensis,Phellodendron amurense,Juglans mandshurica,Fraxinus mandshurica,Betula platyphylla,and Quercus mongolica） and one mixed plantation（P.sylvestris var.mongolica ＋ F.mandshurica ＋ Picea koraiensis ＋ P.amurense ＋ B.platyphylla） in the Urban Forestry Demonstration Research Base of Northeast Forestry University.The concentrations of heavy metals（Cu,Zn,Cd,Ni,Pb and As） were measured,and comprehensive pollution index was used to assess heavy metal contamination in the litter layer according to the background values of heavy metals in black soil in Harbin.Significant or extremely significant differences were observed in the heavy metal concentrations in the litter layer between different plantations.The concentration of Zn was the highest（ranging from 96.09 to 224.21mg·kg-1）,followed by Pb,Cu（Ni）,Ni（Cu）,As and Cd（from 0.30 to 0.80mg·kg-1） in order.The litter layers in the plantations were not obviously polluted by Ni and As,but polluted by Cd,Pb,Zn,and Cu to a certain extent.Ni and As originated from natural materials,but Cu,Zn,Pb,and Cd were anthropogenic input.The comprehensive pollution index for the litter layer of B.platyphylla plantation was the highest,followed by P.Amurense,L.gmelinii,J.mandshurica,P.sylvestris var.mongolica,the coniferous broad-leaved mixed plantation,Q.mongolica,F.mandshurica and P.tabulaeformis var.mukdensis.