Formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) by precursor pathways in oxidation of pesticide alpha-cypermethrin

Summoogum, Sindra L.; Wojtalewicz, Dominika; Altarawneh, Mohammednoor; Mackie, John C.; Kennedy, Eric M.; Dlugogorski, Bogdan Z.

Title: Formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) by precursor pathways in oxidation of pesticide alpha-cypermethrin
Creator: Summoogum, Sindra L.; Wojtalewicz, Dominika; Altarawneh, Mohammednoor; Mackie, John C.; Kennedy, Eric M.; Dlugogorski, Bogdan Z.
Relation: ARC
Relation: Proceedings of the Combustion Institute Vol. 34, p. 3499-3507
Publisher Link: http://dx.doi.org/10.1016/j.proci.2012.06.020
Publisher: Elsevier
Resource Type: journal article
Date: 2013
Description: This contribution assesses the oxidation of the commonly used insecticide and termiticide, alpha-cypermethrin to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F, dioxins) and their precursors, under non-catalytic vapour-phase oxidation, in a flow reactor. No soot was produced during the reaction ruling out the de novo synthesis of PCDD/F. The results span the effect of temperature (300–650 °C) and fuel equivalence ratio (φ of 0.01–7.0), at a residence time of 1 s. XAD-2 resin trapped the PCDD/F which were identified and quantitated by high resolution gas chromatography (HRGC)–ion trap mass spectrometry (ITMS). The reactor walls appear to have no noticeable effect on the initiation of the gas-phase oxidation reactions. The decomposition of alpha-cypermethrin produces two types of PCDD/F precursors, chlorinated benzenes (CBz)/chlorinated phenols (CP) and two-ring species, mainly diphenyl ether and chlorinated diphenyl ethers (CDPE). The CBz/CP precursors comprise chlorobenzene, o-, m- and p-dichlorobenzene, 1,2,3-trichlorobenzene, phenol, 2-monochlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-TriCP, with minor amount of 2,4,5-TriCP. The highest emission factor for PCDD/F was observed at 550 °C and a fuel equivalence ratio of 0.03, corresponding to 19 ng ∑TEQ–WHO2005/g of alpha-cypermethrin and the total dioxins concentration of 141 μg/g of alpha-cypermethrin. These emissions are one of the highest measured from oxidation of presently used pesticides.
Subject: dioxins; fuel equivalence ratio; PCDD/F precursors; pesticide oxidation
Identifier: http://hdl.handle.net/1959.13/1300931
Identifier: uon:20190
Identifier: ISSN:1540-7489
Language: eng
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