化工仓储遗留地块苯系物分布特征研究

A Study on the Distribution Characteristics of BTEX at Remnant Plot of a Former Chemical Depot in Shanghai

对某化工仓储遗留场地开展场地调查工作,共布设103个土壤监测点和99个地下水监测点,在超标污染点位设置不同深度地下水丛式井,对土壤和地下水苯系物进行采样分析。发现,遗留场地苯系物污染严重,尤其是苯和氯苯,地下水中苯和氯苯最大检出浓度分别为892 000、1 040 000μg/L;土壤和地下水苯系物污染具有一致性,在地下水中更易于迁移、扩散;土壤苯系物垂向迁移与自身密度、土壤渗透系数有关,苯类轻质非水相液体易集中在上层土壤,氯苯类重质非水相液体垂向迁移深,在渗透性差的淤泥质黏土层甚至暗绿色粉质粘土层截留。

In order to transfer the land,an environmental site investigation was carried out at a remnant plot of former chemical depot in Shanghai,and 103 soil monitoring spots and 99 groundwater monitoring wells were laid,whilst at incompliant contaminated points were set groundwater cluster wells in different depths to take soil and groundwater samples for analysing benzene series compounds(BTEX).It has found that the contamination of BTEX was serious at the remnant site,especially of benzene and chlorobenzene.The maximum concentrations of benzene and chlorobenzene detected in groundwater were 892 mg/L and 1,040 mg/L,respectively.The BTEX contamination in soil and groundwater distributed consistently,but was more liable to migrate and diffuse in groundwater.The vertical migration of BTEX in soil depended on its own density and soil permeability coefficient.The benzene-based light non-aqueous phase liquids tended to concentrate in the upper soil,and chlorobenzene-based dense non-aqueous phase liquids migrated toward deeper and were intercepted in poorly permeable mucky clay stratum or even in dark green silty clay stratum.