Pollution threshold and high-risk area determination for heavy metals is important for effectively developing pollution control strategies. Based on heavy metal contents in 3627 dense samples, an integrated framework combining the finite mixture distribution model and Bayesian maximum entropy (BME) theory was proposed to assess pollution thresholds, contamination levels and risk areas in an uncertain environment for soil heavy metals. The results showed that the average heavy metal contents were in the order Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, with strong/moderate variation, and the corresponding pollution thresholds were 158.39, 84.29, 47.84, 49.75, 28.95, 18.01, 0.49 and 0.16 mg/kg, respectively. The thresholds were consistently greater than the Zhejiang Province backgrounds but lower than the national risk screening values, except for Cd. Approximately 27.9% of the samples were classified as contaminated at various levels, and they were distributed in the northern, northwestern and eastern regions of the study area. Additionally, 3.73%, 5.34% and 8.22% of the total area were classified as at-risk areas under confidence levels of 95%, 90% and 75%, respectively, through BME theory. The findings provide a reasonable classification system and suggestions for heavy metal pollution management and control.

重金属的污染阈值和高风险区域的确定对于有效制定污染控制策略具有重要意义。基于 3627 个致密样品中的重金属含量，提出了一种结合有限混合分布模型和贝叶斯最大熵 (BME) 理论的集成框架，用于评估不确定环境中土壤重金属的污染阈值、污染水平和风险区域。结果表明，重金属平均含量依次为Zn>Cr>Pb>Cu>Ni>As>Cd>Hg，呈强/中度变化，对应的污染阈值分别为158.39、84.29、47.84、49.75、28.95 ，分别为 18.01、0.49 和 0.16 毫克/千克。除 Cd 外，阈值始终高于浙江省背景但低于国家风险筛查值。约27.9%的样品被归类为不同程度的污染，分布在研究区的北部、西北部和东部地区。此外，根据 BME 理论，在 95%、90% 和 75% 的置信水平下，总面积的 3.73%、5.34% 和 8.22% 分别被归类为风险区域。研究结果为重金属污染管控提供了合理的分类体系和建议。根据 BME 理论，在 95%、90% 和 75% 的置信水平下，总面积的 22% 被归类为风险区域。研究结果为重金属污染管控提供了合理的分类体系和建议。根据 BME 理论，在 95%、90% 和 75% 的置信水平下，总面积的 22% 被归类为风险区域。研究结果为重金属污染管控提供了合理的分类体系和建议。