Comparison of lung radiography and counting of exposure time to magnetopneumography for estimation of total lung dust retention in arc welders.

Magnetopneumography (MPG) is a non-invasive technique to measure the amount of magnetizable dust retained in the lung. This study concerns the relation between MPG measurements of welding fume dust retention in the human lung on the one hand and chest radiography and crude counting of exposure time on the other. Precision and accuracy of the MPG instrument was found to be high. A weak but statistically significant correlation (r = 0.45, P < 0.05) was found between exposure time and retention of magnetizable material in a group of 112 full time manual metal arc welders. The variability was high. Retention rate was estimated on a group level. Chest radiographs of 23 arc welders were reviewed separately in random order by two independent readers who were not aware of MPG findings, occupational anamnesis or the subject's identity and age. No statistically significant correlation was found between MPG and the observer's grading. A weak but statistically significant correlation was found between the readers. We conclude that MPG is highly sensitive to retention of magnetizable material retained in the lung and that the correlation between radiography and MPG reported by previous workers could not be verified in this study. The divergent results may well be due to methodological differences. Investigations using more specific roentgenological methods, such as high resolution computed tomography (HRCT), should be performed.

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.

Mortality in lung and gastrointestinal cancer among shipyard workers.

The risk of shipyard workers acquiring lung cancer and gastrointestinal cancer was investigated retrospectively by analysing the mortality pattern of 365 deceased shipyard workers. Instead of using the proportional mortality ratio (PMR), the odds ratio (OR) was determined according to a method proposed by Axelson, Miettinen and Der Wang. The pattern of causes of death among Swedish males was used as a reference. The OR was 2.3 for lung cancer and 1.4 for gastrointestinal cancer, using death in cancers of other sites (ICD 170-209) as reference diseases. There was a heavy exposure to asbestos, which is the probable cause of the increased risk of lung cancer in this population.