三江平原地区农田土壤中几种重金属空间分布状况

    Spatial Distribution of Heavy Metals in Agricultural Soil in Sanjiang Plain

    • 摘要: 以三江平原地区农田土壤为研究对象,基于网格法取样,运用经典统计学和地统计学方法对研究区域内土壤重金属As、Cr、Cu、Pb和Zn的空间分布特征进行研究。结果表明,三江平原地区5种土壤重金属具有较高的空间异质性,变异系数在30.67% ~ 66.89%之间;As、Cr、Cu、Pb和Zn均具有较强的空间自相关性,空间自相关范围较广; As和Cr的块金值和基台值之比C0/(C0+C)<25%,其空间变异主要由土壤母质、地形和气候等自然因素(结构性变异)引起,Cu、Pb和Zn的C0/(C0+C)在35.8% ~ 43.2%之间,非结构性因素对Cu、Pb和Zn的影响较大;5种重金属元素的空间分布格局不同,土壤各重金属元素在小尺度范围内存在明显的空间变异,除Cu元素外,其他4种重金属元素在大尺度空间范围内均不具有明显的空间分布规律;采用普通克里格插值法得到三江平原地区表层土壤重金属的空间分布图,发现土壤重金属含量与土壤类型、土壤理化性质、土地利用方式以及矿山开采、农业机械化强度、农业灌溉关系密切。

       

      Abstract: A field survey of agricultural soils in the Sanjiang Plain was carried out of agricultural soils using the grid sampling method for analysis of spatial distribution of heavy metals (As, Cr, Cu, Pb and Zn) in the soil by using the geo-statistics and traditional statistics methods. The studied area was 7.31× 104 km2 in total and it was divided into 16km×16 km grids, providing 244 sampling points. Results show that in this area, the heavy metals varied sharply in terms of spatial distribution in the soil with variation coefficients ranging from 30.67%-66.89%; The heavy metals were all quite high in spatial autocorrelation and their spatial autocorrelation was rather wide in range. As and Cr was <20% in C0/(C0+C), showing their spatial variations were mainly affected by natural factors, like soil parent material, topography and climate, while Cu, Pb and Zn varied in the range of 35.8%-43.2% in C0/(C0+C), showing that their main affecting factors were non-structural ones; The heavy metals differed in spatial distribution and were quite obvious in spatial variation on a small area scale. They did not have any specific patterns in spatial distribution on a large area scale, except Cu. A surface soil heavy metals spatial distribution map was worked out using the Kriging interpolation method, revealing ,that heavy metal concentrations in the soil are closely related to soil type, physical-chemical properties, land-use pattern, mining, agricultural mechanization intensity, and agricultural irrigation.

       

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