Analytical Sciences

A Simplified Determination Method of Dioxin Toxic Equivalent (TEQ) by Single GC/MS Measurement of Five Indicative Congeners

Kotaro MINOMO,* Nobutoshi OHTSUKA,* Kiyoshi NOJIRI,* Shigeo HOSONO,* and Kiyoshi KAWAMURA**

*Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
**Environmental Science and Infrastructure Engineering Division, Graduate School of Science and Engineering, Saitama University, 255 Shimookubo, Sakura, Saitama 338-8570, Japan

Here, we proposed a simplified determination method for dioxin (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls (PCBs)) toxic equivalency (TEQ; based on the World Health Organization-2006 toxicity equivalent factor) in environmental samples collected in Japan. This method has estimated the total TEQ from the concentrations of only five indicative congeners, namely, 2,3,4,7,8-pentachlorodibenzofuran; 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin; 1,2,3,7,8-pentachlorodibenzo-p-dioxin; and PCBs of IUPAC Nos. #126 and #105, which were obtained from a single GC/MS measurement using a combination of columns of 10-meter-long DB-5ms (injector side) and 20-meter-long DB-17ms (detector side). Applying this simplified determination method to various environmental samples (ambient air, river water, river sediment, and soil) showed that the estimated TEQ was in good agreement with TEQ obtained by the corresponding official methods. Moreover, this method could estimate the TEQ contributions of the four major dioxin sources in Japan: combustion by-products, pentachlorophenol formulations, chlornitrofen formulations and PCB products.

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