SMALL AIRWAYS FUNCTION IN ALUMINUM AND STAINLESS-STEEL WELDERS

The effect of welding fumes on small airways was studied in 25 male su bjects who welded in aluminium (Al) and to some extent also in stainle ss steel (SS). Despite a low exposure to welding fumes as compared to the permissible exposure limits, excretion of Al in urine was found to be increased in all subjects (median value: 0.29 mmol/mol creatinine on Friday afternoon, as compared to an upper reference level of 0.10 m mol/mol creatinine). In addition, the welders displayed increased prev alences of work-related eye and airways (pharyngitis and non-specific bronchial hyperreactivity) symptoms, as compared to 25 matched control s. Short-term welders (less-than-or-equal-to 2.5 years) had more sympt oms related to the upper airways than did long-term welders, which may indicate a selection. Spirometry, closing volume and volume of trappe d gas (VTG) did not deviate. However, after methacholine inhalation, t he long-term welders had a significantly steeper slope of the alveolar plateau on the single-breath nitrogen wash-out test, and a slight inc rease in VTG, as compared to the short-term welders and the controls. These findings may indicate a welding fume-induced increase in the rea ctivity of the small airways. Because Al welding was far more frequent than SS welding, an association with the former seems likely.