某染料厂地块1,2,4-三氯苯污染分布特征及迁移规律

Distribution and migration characteristics of 1,2,4-trichlorobenzene pollution in a dye factory plot

以北京某染料厂污染地块为例,对5种氯苯类(氯苯、1,2-二氯苯、1,4-二氯苯、1,2,3-三氯苯、1,2,4-三氯苯)挥发性有机污染物在土壤及地下水中的浓度数据进行统计分析。选取土壤及地下水样品中检出浓度、超标倍数较高的1,2,4-三氯苯,分析其在土壤中垂向分布特征及地下水中水平分布特征,利用GMS软件中MT3D模拟1,2,4-三氯苯在地下水中溶质迁移规律。结果表明:土壤样品中5种氯苯类有机污染物最大检出浓度均超过相应筛选值;地下水样品中氯苯、1,2-二氯苯最大检出浓度均未超过相应筛选值,1,4-二氯苯、1,2,3-三氯苯、1,2,4-三氯苯最大检出浓度均超过相应筛选值。土壤中高浓度1,2,4-三氯苯污染物主要集中在0~10 m深度范围内,地下水中1,2,4-三氯苯污染物浓度西北部明显高于东南部。地块内北侧地下水位线有轻微北移现象,各监测井地下水位处于缓慢下降趋势。地块内1,2,4-三氯苯在540 d时运移到地块南侧边界,运移距离为96.2 m。

Taking a contaminated plot of a dye factory in Beijing as an example,statistical analysis was carried out on the concentration data of five chlorobenzene volatile organic pollutants(chlorobenzene,1,2-dichlorobenzene,1,4-dichlorobenzene,1,2,3-trichlorobenzene,1,2,4-trichlorobenzene)in soil and groundwater.1,2,4-trichlorobenzene with high detected concentrations and exceedance multiples in soil and groundwater samples was selected,its vertical distribution characteristics in soil and horizontal distribution characteristics in groundwater were analyzed,and the solute migration law of 1,2,4-trichlorobenzene in groundwater was simulated by using MT3D in GMS software.This result indicated that the maximum detectable concentrations of the five chlorobenzene organic pollutants in soil samples all exceed the corresponding screening values,the maximum detectable concentrations of chlorobenzene and 1,2-dichlorobenzene in groundwater samples did not exceed the corresponding screening values,and the maximum detectable concentrations of 1,4-dichlorobenzene,1,2,3-trichlorobenzene and 1,2,4-trichlorobenzenene exceed the corresponding screening values.High concentration of 1,2,4-trichlorobenzene in soil was mainly concentrateded in the range of 0-10 m depth.The concentration of 1,2,4-trichlorobenzene in groundwater in the northwest was significantly higher than that in the southeast.There was a slight northward movement of the groundwater level line on the north side of the plot,and the groundwater level of each monitoring well was in a slow downward trend.1,2,4-trichlorobenzene in the block migrated to the southern boundary of the block at 540 d,with a migration distance of 96.2 m.The research results could provide a theoretical reference for precise control and reasonable restoration of polluted plots.