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

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.