title: Comparison between aqueous-phase and gas-phase exposure protocols for determining the mutagenic potential of nitrogen dioxide and the gas fraction of welding fumes.
abstract: Nitrogen dioxide and the gas fraction of welding fumes, a complex gas mixture which contains high concentrations of nitrogen dioxide, were tested for mutagenicity in Salmonella typhimurium tester strains, TA1535 and TA1538. A comparison between 2 exposure protocols, aqueous phase and gas phase, was made to evaluate the sensitivity of each in measuring the mutagenic potential of the gases. In the aqueous-phase exposure, a suspension of cells in an isotonic salt solution was exposed by bubbling the gas through the culture. In the gas-phase exposure, the plated cells were exposed to the gas in a chamber. For both gases tested, the gas-phase exposure resulted in a higher reversion frequency than the aqueous-phase exposure. Furthermore, we found that nitrogen dioxide accounted for only a fraction of the mutagenicity observed for the gas fraction of welding fumes.
authors.forename: N W
authors.initials: NW
authors.lastname: Biggart
authors.forename: R R
authors.initials: RR
authors.lastname: Rinehart
mesh_terms: D005374:Filtration; D005740:Gases / Q000633:toxicity*; D009152:Mutagenicity Tests; D009153:Mutagens; D009585:Nitrogen Dioxide / Q000633:toxicity*; D012486:Salmonella typhimurium / Q000187:drug effects; D014867:Water
chemical_list: D005740:Gases; D009153:Mutagens; D014867:Water; D009585:Nitrogen Dioxide