海南岛农田土壤重金属背景值评价方法研究——以铬为例

Background Estimation of Cr in Arable Land Soil of Hainan,China

采用迭代剔除法、累积频率法、95%置信上限法和几何均值与标准差求算法分别对海南岛农田土壤铬含量进行背景值评价,并筛选适用于该区农田土壤重金属元素背景值的评价方法。研究结果表明研究区土壤铬含量比全国土壤铬含量水平略低,但空间变异性较高。置信上限法估算得到的土壤铬背景值最高,其他3种方法求算得到的土壤铬含量背景值结果一致。几何均值和标准差求算法得到的土壤铬背景值(28.8 mg/kg)可作为研究区农田土壤的铬背景含量,该方法可避免背景值被估计过高而掩盖人为影响,且计算简单,故可用于海南农田土壤重金属元素背景值评价。

The methods of Iterative 2-σ Technique, Accumulative Frequency Method, Upper Confidence Limit （UCL09s）and Geometric Mean and Geometric Standard Deviation（GM＋2GSD）were used to estimate the background concentration of Cr in the soils in Hainan island and to determine the method for estimation of heavy metals background concentration in arable land soils. The result indicated that, the content of soil Cr was more or less lower than the national average concentration, and had a higher variability. The result of UCL095, 54.2 mg/kg, was the highest of the four methods and the results of three other techniques were highly consistent. The estimation result of GM＋2GSD（28.8 mg/kg）was considered as the soil background concentration of Cr in the studied area. This method could be applied to estimate the background concentration of heavy metals in arable soils for it is simple to calculate and prevent excessive estimation.