US EPA

Numerous research studies have been conducted to establish indicator compounds for fast and less costly prediction of polychlorinated dibenzo-p-dioxin/dibenzofurans (PCDD/F) toxix equivalent (TEQ) concentrations. Chlorobenzene has been suggested as one potential PCDD/F TEQ predictor, as have other compounds: chlorophenols, polychlorinated biphenyls (PCBs), and polychlorinated aromatic hydrocarbons (PAHs). Good correlation results were reported between some mono- to tri-chlorinated PCDD/F isomers and TEQ values. The interest in the use of mono- to tri-chlorinated isomers as possible indicator compounds for TEQ PCDD/F is due to the similarities of these compounds with TEQ-based congeners and the emergence of fast, in-situ, on-line measurements adapted to PCDD/F measurement, such as resonance enhanced multi-photon ionization (REMPI) with time of flight mass spectrometry (TOFMS). However, there is still uncertainty in using these compounds as indicators because their relationships with TEQ may be plant- and operating-condition-specific. The aim of this study is to assess and determine PCDD/F isomers which could be used as indicators for PCDD/F TEQ as well as to use the relationship between indicators and TEQ to understand formation mechanisms.

Oh, J.; Touri, A.; Gullett, B.; Mulholland, J. 2003. PCDD/F TEQ Indicators and the Mechanistic Implications. Organohalogen Compounds 60:505-508.

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