Effects of exposure to welding fume: an experimental study in sheep.

Welding fume contains various metals and pulmonary effects from their inhalation are largely unknown. We have studied the effects of exposure to welding fume in sheep. The animals were exposed to either a bolus dose of welding fume solution or to five weeks daily exposure. Lung physiology parameters were studied and biopsies taken. Magnetopneumography was used to register the longterm exposure. Acutely exposed animals had elevated pulmonary arterial pressure. Arterial oxygen tension was reduced after fume instillation. These animals had accumulation of iron (Fe), magnesium (Mg) and manganese (Mn) in the lungs. Mn was elevated 40 times. Longterm exposed sheep increased the iron oxide accumulation significantly in lungs as seen with the magnetopneumographic technique. Following long term exposure, Mn was the metal most heavily retained in the lungs. Metals like Mn, Fe and Mg retained in the lungs can possibly give negative health effects. Besides this, the metals could be used for quantitation of welding fume exposure.