某石油化工场地土层挥发性有机物的污染特征  

Contamination characteristics of volatile organic compounds in the subsoil of a petrochemical contaminated site

作　　者：蔡五田[1] 张敏[1] 刘雪松[1] 李金英[1] 王永池[1] 

机构地区：[1]中国地质调查局水文地质环境地质调查中心,保定071051

出　　处：《水文地质工程地质》2011年第2期89-96,共8页Hydrogeology & Engineering Geology

基　　金：中国地质调查局国土资源大调查项目(1212010634606)

摘　　要：在调查华北平原一个污染年限超过35年的石油化工场地时,采用便携式仪器土层测气方法,快速、准确地测定了场地内40多个钻孔不同深度土层中挥发性有机物(VOCs)的浓度。基于对场地地质水文地质条件的认识,以及通过对大量数据的分析对比和应用空间变异分析方法,得出了对场地土层介质中VOCs污染特征的如下认识:(1)土层VOCs浓度的垂向变化可概括为污染源淋滤型、包气带扩散污染型、地下水波动带污染型和混合污染型四种污染类型;(2)在包气带砂土层和粉土层中,VOCs的扩散规律可近似用指数模型描述;(3)包气带土层中VOCs优先积聚在渗透性强的砂性土层中,砂土层中VOCs浓度是粉土层中VOCs浓度的1.5～12倍,平均3.76倍;(4)土层VOCs浓度的水平变异性表现为包气带土层的变异性要比地下水波动带土层大,且水平变异性能在25m尺度内得到充分显示;而土层VOCs浓度的垂向变异性随地而异,变化复杂,很难用统一的一个量化尺度来表征。本文对这一典型污染场地的剖析,有助于从事污染场地调查人员认识我国华北平原石油化工类场地的污染特征,并为调查与治理类似污染场地提供技术依据。In the course of investigation of a petrochemical contaminated site with a span of 35 years,the authors used a portable detecting soil gas method to rapidly and accurately detect volatile organic compounds（VOCs） concentrations in subsoil at various depths in more than 40 boreholes.Based on the knowledge of geology and hydrogeology near the site,data analysis and comparison,and using space variogram analytical method,the characteristics of VOCs concentration distribution in subsoil are summarized as follows：（1） four contamination profiles in subsoil can be figured out,i.e.source leaching type,unsaturated zone diffusion type,groundwater fluctuation zone type,and mixed contamination type;（2） in both the sand layer and the silt layer,variations in VOCs concentration with distance can be described with exponential functions;（3） VOCs in the unsaturated zone are preferred to accumulate in higher permeable sand layers,showing that VOCs concentrations in sandy layers are 1.5 to 12 times and 3.76 in average higher than in silt layers;（4） horizontal variation in VOCs concentration in the unsaturated zone is greater than that in groundwater fluctuated zone and horizontal lag distance of VOCs concentration is about 25 m;while vertical variation in VOCs concentration varies greatly from place to place,and it is difficult to use a single scale to describe vertical variogram features of the VOCs.It is believed that these discoveries will assist contaminated site investigators to better understand the characteristics of such petrochemical contaminated sites in the North China Plain,and provide technical basis for surveying and remedying this kind of site.

关 键 词：石油化工类污染场地 便携式仪器土层测气法 挥发性有机污染物(VOCs) 土层污染特征 

分 类 号：X53[环境科学与工程—环境工程]