黑土区小流域土壤重金属生态危害与来源解析

Ecological risk and source analysis of soil heavy metals in a Mollisol watershed of China

为探明黑土区土壤重金属污染状况,以海沟河小流域为研究区域共采集136个土壤样品,分别测定土壤样品中重金属Cu、Zn、Hg、As、Ni和Cr的含量。采用潜在生态危害指数进行重金属污染评价,并通过主成分分析和正定矩阵因子分析的方法进行土壤重金属污染来源解析,结果表明:1)参照黑龙江省土壤背景值,该地区土壤中重金属Cu、Zn、Hg、Ni和Cr均存在超标现象,超标率分别为16.2%、28.7%、93.4%、48.5%和19.1%,且均处于中等变异程度,都受到人为因素的影响;2)潜在生态危害指数表明该地区土壤重金属整体处于低风险等级,除Hg外其他重金属元素也都处于低风险等级,而Hg元素处于中风险等级,具有潜在的生态危害性;3)通过源解析基本可以确定该地区重金属污染有4种来源,分别为自然源与大气沉降源、工业农业活动源、生活污染源和交通源,其中Hg的主要来源是燃煤活动,Cu主要是由于化肥的过量施用,Zn、Ni和Cr的累积主要与交通运输有关。

To explore the potential ecological risk and pollution source of heavy metals,including Hg,As,Cr,Cu,Zn,and Ni in Mollisol water shed,a total of 136 samples were taken as study materials.The potential ecological risk index,correlation analysis,principal component analysis and PMF analysis were employed to reveal the heavy metal pollution situation and source.The main results were as follows:1)The metal pollution of Cu,Zn,Hg,Ni and Cr have exceeded the soil background value of Heilongjiang Province,and the over standard rates were 16.2%,28.7%,93.4%,48.5%and 19.1%,respectively.They all showed a moderate variation and were impacted by human activities;2)The potential ecology risk index indicated that Hg was at a medium risk level and other elements were at a low risk level;3)Pollution source analysis showed that the heavy metal pollution was mainly from 4 kinds of sources,e.g.natural and atmospheric subsidence source,industrial and agricultural activities source,domestic pollution source and transportation source.The main source of Hg was coal-fired activity,Cu pollution was mainly due to excessive application of chemical fertilizer,and the accumulations of Zn,Ni and Cr were mainly related to transportation.