某农药厂周围土壤四氯化碳污染特征研究

Pollution Characteristics of Carbon Tetrachloride in Soils Near A Pesticide Plant

通过对土壤和土壤孔隙水四氯化碳含量的测试,研究了某农药厂附近土壤四氯化碳污染特征。该农药厂排污渠和供水井附近的土壤中均检测出四氯化碳和氯仿,含量分别为0.7～42.2μg·kg-1和2.6～26.5μg·kg-1;土壤孔隙水四氯化碳主要在农药厂供水井附近检出,含量1.4～2.8μg·L-1。污染源区土壤中不存在四氯化碳污染池。四氯化碳在土壤中的分布主要受四氯化碳来源、四氯化碳的挥发作用和四氯化碳的自然衰减作用所控制。四氯化碳最高含量均出现在农药厂供水井附近,四氯化碳主要在3m以下的土层中检测出,且随深度增加而增加;表层土壤四氯化碳含量相对较低或未检出。

Carbon tetrachloride （CT） is a common groundwater and soil contaminant. Pollution characteristics of CT in soils near a pesticide were studied through testing the CT contents in soils and pore water of the soils. CT and chloroform were detected in the soils near the effluent drain of the pesticide plant and the water supply well of the pesticide plant, of which the contents are 0.7-42.2μg·kg^-1 and 2.6-26.5μg·kg^-1 respectively. Carbon tetrachloride of pore water with the content of 1.4-2.8μg·kg^-1 was detected near the water supply well of the pesticide plant, while chloroform was not detected in the pore waters. Further analysis indicated that CT does not exist as CT DNAPL pool. The distribution of CT in the soils is controlled by the sources of CT, the volatilization of CT and the natural degradation of CT. Therefore, CT is detected in the soils with the depth than 3m, and CT was not detected or CT content is relative lower in the topsoil. CT content increases with the increase of the soil depth and the highest content is in the soils near the water supply well of the pesticide plant.