沈阳浑河冲洪积扇土壤的重金属空间分布特征及来源

Spatial Distribution and Sources of Heavy Metals in Soils from Alluvial and Diluvial Fan of Hun River in Shenyang

以沈阳市浑河冲洪积扇下游的彰驿站镇为研究区,实测分析了98个土壤表层（0~20 cm）样品中的w（Cr）、w（Cu）、w（Mn）、w（Ni）、w（Pb）、w（Zn）、w（Fe）、w（Hg）、w（As）和w（Cd）,运用地统计学空间分析与多元统计源分析相结合的方法,对土壤中各重金属的质量分数、分布特征及其来源进行研究.结果表明：除w（As）外,其余重金属的质量分数均超过辽宁省土壤中相应重金属的背景值,其中Hg和Cd积累最为显著,w（Hg）和w（Cd）分别是其相应背景值的2.33和5.44倍,对应的采样点中高于背景值的比例均接近100%,呈明显累积趋势.地统计学空间分析表明,w（Ni）、w（Cr）和w（Fe）受土壤母质、地形等结构性变异主导,其他重金属质量分数主要受人为活动等随机因子的影响,w（Cu）、w（Pb）、w（Zn）、w（Hg）和w（Cd）分布规律比较相似,元素来源较为集中;10种重金属元素的来源可分为3类,其中Cr、Ni、Fe和Mn主要受自然因素的影响,Pb、Zn、Hg和Cd主要受人为因素的影响,而Cu和As受2种因素的协同影响.

98 topsoil samples were sampled in Zhangyizhan Town, a suburb region of Shenyang City, which located in alluvial and diluvial fan of Hun river. The contents, distribution characteristics and sources of ten heavy metals in the topsoils were analyzed with the methods of combined geostatistical and multivariate statistics. The results show that the average concentrations of the Cr, Cu, Mn, Ni, Pb, Zn, Fe, Hg and Cd in the topsoils are higher than their background values of soils in Liaoning Province. Especially, the Hg and Cd contents are 2.33 and 5.44 times higher than the background values, respectively, and over-limit ratio of these two elements are close to 100% , showing an obvious cumulative trend. Spatial structure analysis shows that the distribution of the Ni, Cr and Fe is influenced by the soil structural variations, such as regional topography, and other elements are mainly affected by random factors of human activities. It could also be found that the contents of Cu, Pb, Zn, Hg and Cd show a very similar spatial pattern, indicated a similar source. The results of correlation analysis and factor analysis show that the sources of these elements can be divided into three categories： the Cr, Ni, Fe and Mn are mostly affected by natural factors, the Pb, Zn, Hg and Cd are mostly affected by anthropogenic influence, and the Cu and As are affected by both of the two factors.