Abstract
The persistent and hazardous nature of some legally regulated dioxins, including PCDD/Fs and dioxin-like PCBs, makes them of particular concern. However, it is currently not possible to estimate the potential risk of exhaust gases and to act on dioxin measurement data taken in real time at incineration plants, since obtaining results from samples takes time. This study investigates the potential for real-time measurement of organic halogens using atomic emission spectrometry employing radio-frequency helium plasma. Investigations were conducted on the adsorption characteristics of various graphite-based dioxin adsorbents, the basic dose-response relationships of this detection system, and actual gas sampling/measurement using a continuous gas sampling apparatus. The following results were obtained. i)The relationship between halogen amount ratio and peak area ratio using chlorobenzene and bromobenzene as standard compounds showed good linearity. The coefficients between the two parameters varied from 0.66 to 1.4, averaging 1.0. ii)The Carbotrap C tube collected compounds with a boiling point above 180°C; addition of a Carbopak X tube made it possible to collect a wide range of gaseous organic halogens.
The gas sampling tube was incorporated into a semi-continuous sampling apparatus and used for flue gas sampling at actual incineration plants. The sum of the concentrations of organic chlorines and bromines during two five-day measurement periods varied from 0.61 to 9.4μg/m3. This rapid and easy measurement method of organic halogens thus has considerable potential for the management of hazardous substances at incineration plants.
