“精确”假象与可靠决策: 土壤污染调查数据的描述性统计与地统计插值稳定性对比研究

Precision Illusion and Reliable Decision-making: A Comparative Study of Stability between Descriptive Statistics and Geostatistical Interpolation in Soil Pollution Investigation Data

  • 摘要: 工业场地土壤污染精准评估是风险管控与修复决策的基础。当前实践中, 地统计插值方法因能提供直观污染分布图而得到高度重视, 但其结果受采样策略的影响大, 稳定性存疑。本研究基于同一工业场地的两次独立调查数据, 针对砷污染, 系统比较了数值统计分析与空间格局表征结果的稳定性差异。分析表明: 关键统计量如均值95%置信上限、中位数和95%分位数表现出较高稳定性, 尤其是均值95%置信上限相对偏差<5%, 适用于风险决策; 克里金插值结果稳定性较差, 污染羽边界、热点位置和超标面积估算变异显著, 尤其是在空间自相关性弱的情况下, 插值结果更多地反映了采样点分布而非真实污染格局。本研究提出, 过度依赖单一的地统计插值结果可能存在决策风险, 建议构建以稳健统计量为核心、辅以空间趋势可视化及不确定性识别的综合评估框架。本研究为提升污染场地评估结果可靠性与决策科学性提供了重要依据, 对场地调查技术的发展具有实践指导意义。

     

    Abstract: Accurate assessment of soil contamination forms the scientific basis for risk management and remediation strategies at industrial sites. Spatial interpolation techniques, particularly kriging, are widely used today as they effectively visualize contamination distributions. These methods exhibit limited stability owing to their strong dependence on sampling strategies. Based on two independent sampling campaigns conducted on the same site (with 229 and 116 sampling points, respectively), this study systematically compared the stability differences between statistical analysis and spatial characterization results for arsenic contamination. The results demonstrate that key statistical parameters, particularly the 95% upper confidence limit (95% UCL) of the mean, the median, and the 95th percentile, exhibited high stability with relative deviations generally below 15%. The 95% UCL of the mean demonstrated remarkable stability, with a relative deviation of less than 5%, confirming its strong suitability for risk assessment applications. In contrast, the results obtained through Ordinary Kriging interpolation displayed poor stability. The delineation of contamination boundaries, identification of hotspot distributions, and quantification of risk-exceeding zones displayed marked inconsistencies compared to the established control threshold. This instability was particularly pronounced in contexts characterized by weak spatial autocorrelation, as indicated by nugget-to-sill ratios close to 1, where the interpolation results reflected the spatial distribution of sampling points rather than the true contamination pattern. The study warns that relying solely on spatial interpolation risks flawed remediation decisions, causing either excessive or inadequate remediation efforts. The study advocated for an integrated assessment framework that prioritizes rigorous statistical parameters as its foundation, complemented by spatial trend visualization and systematic uncertainty quantification. These findings can strengthen contamination assessment reliability and decision-making rigor, guiding next-generation site investigation technologies.

     

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