手持式XRF在土壤调查修复项目中应用的可靠性分析

Reliability analysis of handheld XRF application in soil investigation and remediation projects

  • 摘要: 为确定手持式X射线荧光光谱仪(XRF)测量精度和准确度是否能够满足土壤环境快速检测要求,以山东省济宁市某地块土壤污染状况调查项目为背景,分别采用XRF快速检测仪检测和实验室检测方法对浅层土层(0.2~0.5 m)和深层土层(1.5~2.0 m)样品中砷(As)、铜(Cu)、铅(Pb)、锌(Zn)和镍(Ni)5种元素浓度进行检测。结果表明:浅层土层重金属As的XRF检测值普遍高于实验室检测值,Cu、Pb、Zn、Ni的XRF检测值普遍低于实验室检测值,误差普遍在±30%以内;浅层土层的重金属元素XRF检测值与实验室检测值普遍相对偏差(RD为−33.82%~23.53%)及总体相对偏差标准差(6.79~19.52)小于深层土层(分别为−30.26%~98.36%、9.53~49.77),相对偏差的离散程度小于深层土层;浅层土层的重金属的决定系数(R2为0.776 2~0.954 9)普遍高于深层土层(R2为0.776 2~0.954 9),相关性高于深层土层。野外使用XRF对土壤样品中重金属进行检测时,所取的土壤样品尽量避免大颗粒,对样品待测面进行压实、压平处理,对于含水率高的样品应适当进行干燥处理,以降低检测误差。虽然手持式XRF检测存在一定误差,但在土壤污染状况调查项目中可以较好地反映土壤元素浓度范围,具有较高的可靠性,可以满足项目土壤快速检测需求。

     

    Abstract: In order to determine whether the measurement precision and accuracy of the handheld X-ray fluorescence spectrometer (XRF) can meet the requirements of rapid detection of soil environment, in the context of one soil pollution survey project in a certain plot of Jining City, Shandong Province, the concentrations of arsenic (As), copper (Cu), lead (Pb), zinc (Zn), and nickel (Ni) were detected by XRF rapid detection and laboratory methods. The samples were collected from shallow soil layers (0.2-0.5 m) and deep soil layers (1.5-2.0 m). The results indicated that for shallow soil layers, XRF measurements of heavy metal As consistently exceeded laboratory data, while XRF measurements of heavy metals Cu, Pb, Zn, and Ni were lower within an error of ±30% compared to laboratory measurements. The relative deviations (RD) and overall relative deviation standard deviations of heavy metal elements in shallow soil layers (RD: −33.82%-23.53%, standard deviation: 6.79-19.52) were generally smaller than those in deep soil layers (RD: −30.26%-98.36%, standard deviation: 9.53-49.77), and the dispersion degree of relative deviation in shallow soil layers was smaller than that of deep soil layers. Moreover, the determination coefficients (R2) for heavy metals in shallow soil layers (R2: 0.7762-0.9549) were consistently higher than those in deep soil layers (R2: 0.7762-0.9549), indicating a stronger correlation. When XRF was employed for in-field detection of heavy metals in soil samples, it was recommended to avoid large particles in the samples, compact and flatten the testing surface and, for samples with high moisture content, carry out appropriate drying to minimize detection errors. Despite the inherent limitations of handheld XRF detection, the method demonstrates acceptable accuracy and reliability in reflecting the concentration range of soil elements in soil pollution survey projects, meeting the rapid detection requirements of such projects.

     

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