A measuring method of chlorobenzenes as a convenient substitute index of dioxins in stack gas from waste incineration facilities

Much labor, high technical skill and extreme cost are required to measure dioxins for obtaining the toxic equivalent quantity (TEQ) values. On one side, it was found that there were high amounts of chlorobenzenes (CBZs) in the flue gas from waste incineration facilities, and they are also thought to be one of the principal precursors for dioxins. The concentrations of CBZs could be used as a convenient substitute index to the TEQ values for controlling and monitoring dioxins in stack gas from waste incineration facilities as shown in another report. In this study, collection efficiencies in the sampling performed by a convenient train which was composed of two bottles containing water and diethylene glycol in a cooling box, recoveries in the evaporation of the extract by an evaporator, proper procedure of the concentration by nitrogen purge were investigated for measuring CBZs. It was found that tetra-, penta-, and hexa-chlorobenzenes (Cl4-6BZs) whose boiling points are higher than ca. 240°C could be sufficiently collected and recovered in the sampling and the evaporation. For sufficient recoveries of Cl4-6BZs in the concentration by the nitrogen purge, the final volume should be larger than 200 μl with a proper receiver of the K-D concentrator at 35°C. However, Cl1-3BZs were lost in each of the procedures.