济南市小清河流域表层沉积物中重金属的空间分布、生态风险及源解析

Spatial Distribution,Ecological Risk and Source Apportionment of Heavy Metals in Sediments from Xiaoqinghe Watershed of Jinan

对小清河流域40个表层沉积物样品中的7种重金属元素(As,Cd,Cr,Cu,Ni,Pb,Zn)进行了检测,并分析其空间分布、潜在生态风险和来源,结果表明:7种重金属元素的平均质量分数从大到小依次为Zn,Cr,Pb,Cu,Ni,Cd,As,平均质量分数依次为418.44,257.79,250.49,73.35,56.89,6.20,4.37mg/kg.除As外,其余6种重金属元素均出现了明显的富集;空间上,石河的重金属总量最高,工商河次之.研究区生态风险危害指数为324.08~4467.36,具有强或很强的生态风险,Cd也具有很强或极强的生态风险,80%的采样点Pb具有中等以上生态风险,Cr,Cu,As、Ni和Zn具有轻微的生态风险.利用主成分分析法(PCA)和正定矩阵模型(PMF)对重金属的来源进行定性和定量分析,工业废水对小清河流域沉积物中重金属的贡献最大(48.7%),其次是电镀点源污染(24.6%)、交通源(23.7%)和自然来源(3.0%).

In this study,the concentrations of As,Cd,Cr,Cu,Ni,Pb and Zn have been analyzed by ICPMS,and their distributions,ecological risk and sources been further investigated.The results show that the mean concentrations of heavy metals in sediment is in the descending order of Zn〉Cr〉Pb〉Cu〉Ni〉Cd〉As,and the mean concentrations were 418.44,257.79,250.49,73.35,56.89,6.20,4.37 mg·kg-1,respectively.The contents of heavy metals（Cd,Cr,Cu,Ni,Pb and Zn）in sediments are higher than the background values of the local soils,which have high degree of enrichment.The sample in Shihe River has the highest concentration of heavy metals,followed by Gongshanghe River.Based on the calculation of potential ecological risk index（RI）,the RI of the study area is in the range of 324.08-4467.36,which has high to very high potential ecological risks.Cd is of very high to extremely high risk,80% of Pb is of medium to high risk,and the other heavy metals are of slight risk.Qualitative and quantitative analysis of heavy metals are performed by means of Principal Component Analysis（PCA）and Positive Definite Matrix（PMF）models.Source apportionment results show that the highest contribution to heavy metals in sediments originates from industrial sewage（48.7%）,followed by electroplating industries（24.6%）,traf？c pollution（23.7%）and natural sources（3.0%）.