Effect of welding fume on rat alveolar macrophage viability, respiratory burst, and tumor necrosis factor-a release.
We compared the in vitro, responses of alveolar macrophages (AMs) to welding fumes assessing viability, respiratory burst, and tumor necrosis factor-a (TNF-a) release. Fume was collected during fluxcored manual metal arc (MMA) and gas metal arc (GMA) welding using two consumable electrodes: stainless steel (SS) or mild steel (MS). The elemental constituents of the fume was identified by energy dispersive spectroscopy: 1. MMA-SS: 22.3% K, 19.4% Fe, 13.1% Cr, 12.6% Si, 8.2% Ca, 8.0% Mn, 5.0% Na, 4.3% Ti, 8.1% other; 2. GMA-SS: 52.3% Fe, 22.2% Cr, 18.3% Mn, 4.9% Ni, 2.3% Si; 3. GMA-MS: 89.2% Fe, 8.2% Mn, 2.6% Si. AMs were recovered from CD/VAF rats by bronchoalveolar lavage, incubated with the fume (0.025 and 0.10 mg/ml) suspended in saline, and then assayed 30 min, 12 and 24 hr later. Following a 30 min incubation at 0.025 mg/ml, the respiratory burst increased 26.7%, 17.2%, and 7.9% above control (AMs exposed to no particles) in AMs exposed to MMA-SS, GMA-SS, and GMA-MS fumes, respectively. After 12 hr at the same concentration, a significantly elevated (p<0.05) amount of TNF-a was released from the AMs when incubated with the MMA-SS fume as compared to the other fumes. Following a 24 hr incubation with a concentration of 0.10 mg/ml, the MMA-SS fume caused a 61.2% loss of AM viability as compared to a 42.5% and 39.7% loss from the GMA-SS and GMA-MS fumes, respectively. We have demonstrated that SS fumes were more toxic than MS fumes, consistent with higher non-ferrous constituents in SS. The SS fume from MMA welding had the greater effect on AM function, probably due to fluxes used in MMA.
The Toxicologist. Society of Toxicology 35th Annual Meeting, March 10-14,1996, Anaheim, California