MEASUREMENT OF MUTAGENIC EMISSIONS FROM THE INCINERATION OF THE PESTICIDE DINOSEB DURING APPLICATION OF COMBUSTION MODIFICATIONS

The dinitroaromatic pesticide dinoseb was incinerated in a 0.6-MW (2 000 000 Btu/h) precombustion chamber burner/package boiler simulator that employed two combustion-modification technologies for NO(x) control, staged combustion, and/or reburning. The Salmonella (Ames) mutagenicity assay was used to monitor the effect of these control technologies on the mutagenicity of the particle-bound and semivolatile dichloromethane-extractable organics of the emissions. The combination of staged combustion and reburning reduced not only the NO(x) emissions (by > 96%) compared to the absence of these two control technologies, but also the mutagenic potency of the emissions (by approximately 70%, -S9) and the mutagenic emission factor (by approximately 60%, -S9) compared to that of staged combustion alone. The mutagenic emission factor in the presence or absence of S9 was similar to that obtained for the burning of fuel oil for residential heating (approximately 1 revertant/kg of fuel x 10(5), +S9). Mutagenicity bioassays suggested that approximately 70-90% of the mutagenic activity of the organic emissions in the absence of S9 may be due to nitroaromatics. However, chemical analysis for a variety of nitroaromatics indicated the presence of only a few such compounds at detectable levels. In the presence of S9, the mutagenic potency of the organic emissions was increased approximately 50% by the addition of reburning. This is consistent with the conversion by reburning of nitroaromatics, which are mutagenic in the absence of S9, to polycyclic aromatic hydrocarbons (PAHs), which are mutagenic in the presence of S9.