某大型焦化企业污染场地中多环芳烃空间分布的分异性特征

以我国某大型焦化企业污染场地为研究对象,应用非参数地统计学中指示克里格方法对场地中0～50 cm深度土壤的多环芳烃（PAHs）空间分布进行污染概率分析,并绘制在设定阈值条件下的概率分布图.结果表明,对采样样点数据进行指示转换后,可获取较为稳健的指示半变异函数,但由于样本的空间变异原因,导致样本间空间相关性差;所研究的4种PAHs污染概率在空间分布上具有相似性,概率超过45%的区域主要分布于炼焦、煤气净化、焦油化产品回收等生产工艺的车间中,位于厂区的中部及西北和东南,污染较为严重;概率〈45%的区域主要分布在备煤和煤气净化等生产工艺车间,位于厂区西南和东北区域.污染概率预测结果与该场地污染源的产生和分布状况相一致.研究结果对后续的污染场地修复治理范围确定和土方量估算提供了重要参考。

Heterogeneous Characteristic of PAHs' Spatial Distribution in a Large Coking Site of China

A large coking contaminated site was selected to study the PAHs' spatial distribution probability in surface-soil (0-50 cm) through the indicator kriging of the non-parametric geostatistics, and the map of probability distribution with a contaminant target was plotted over the entire site. Results indicated that the indicator semivariograms were stable after the conversion of sample data, but the poor correlation of spatial samples was observed due to the spatial variability. In this site, the distribution of the contamination probability of four PAHs' showed a similar characteristic, and the areas with a probability of more than 45% were mainly distributed in production process workshops for coking, gas purification, tar products etc, of the central, northwest and southeast site with serious contamination, while the areas with a probability of less than 45% were mainly distributed in coal preparation, gas purification workshops of the southwest and northeast site. Based on the above analysis results, we can draw a conclusion that the forecast probability results are consistent with the occurrence and distribution of pollution sources, which is important for defining the remediation boundary and calculating the contaminated soil volume.