| Persistant organic pollutants (POPs) are refractory, bioaccumulate and toxic organic compounds. The properties of POPs lead to the hazardous effects to ecological system and human health. It is significant to study the distribution and level of POPs in multi-environmental medium. The purpose of this work is to establish the pretreatment method and the GC-ECD analytical method to determine the concentration of hexachlorobenzene (HCB) in environmental samples. The main conclusions are as follows:1) The operation parameters of GC-ECD were optimized for determination of HCB. The calibration curve, linear range, the limit of detection, and the limit of quantitative detection were established;2) Ultrasonic Extraction of Hexachlorobenzene (HCB) from sediments was studied. The results showed that the stability of HCB was very well in different treatments of ultrasonic extraction. The conditions of ultrasonic extraction were optimized as follows: in 10mL sealed test tube, 6mL acetone: hexane(V:V, 1:1) was used as extractant, 90W ultrasonic power, and 40min extraction time, under 35-40℃, for twice. The average recovery of HCB from spiked sediments was 84.8%. The relative standard deviation was 1.92% (n=10). Compared with traditional extraction methods (Soxhlet extraction and shake-flask extraction), ultrasonic extraction showed higher extraction efficiency, shorter time, simplicity of operation and less solvent consumption. The developed method was successfully applied to determine the HCB in practical sediment sample;3) The distribution characteristics of HCB discharged from a chemical plant in water, soil, sediment and plant sample was studied. The concentration level of HCB, the factor affected on the distribution characteristics of HCB, the trend of HCB in the environment was studied.
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