Manganese, Iron, and Total Particulate Exposures to Welders

Abstract

Welders are exposed to a variety of metal fumes, including manganese, that may elevate the risk for neurological disease. This study examines several large data sets to characterize manganese, iron, and total particulate mass exposures resulting from welding operations. The data sets contained covariates for a variety of exposure modifiers, including the presence of ventilation, the degree of confinement, and the location of the personal sampler (i.e., behind or in front of the welding helmet). The analysis suggests that exposures to manganese are frequently at or above the current ACGIH(R) threshold limit value of 0.2 mg/m(3). In addition, there is evidence that local exhaust ventilation can control the exposures to manganese and total fume but that mechanical ventilation may not. The data suggest that higher exposures are associated with a greater degree of enclosure, particularly when local exhaust ventilation is absent. Samples taken behind the helmet were, in general, lower than those measured outside of it. There were strong correlations among manganese, iron, and total particulate mass exposures, suggesting simple equations to estimate one fume component from any of the others.

Levels and predictors of airborne and internal exposure to manganese and iron among welders

“…We confirmed the close correlations between Mn, Fe, and welding fumes as shown with data from large welding databases. 10 The median concentrations of respirable Mn (62 mg/m 3 ) and inhalable Mn (73 mg/m 3 ) were comparable to a median of 60 mg/m 3 from 114 Mn measurements of the database of The Welding Institute (accessible from http://www.twi.co.uk) and to a geometric mean of 97 mg/m 3 in 96 Russian welders. 21 Due to the skewed data distribution, the arithmetic mean of respirable Mn was 258 mg/m 3 in our data set and corresponds to 270 mg/m 3 reported as mean Mn from the welding database of the Occupational Safety and Health Administration (OSHA).…”

“…21 Due to the skewed data distribution, the arithmetic mean of respirable Mn was 258 mg/m 3 in our data set and corresponds to 270 mg/m 3 reported as mean Mn from the welding database of the Occupational Safety and Health Administration (OSHA). 10 Although large collections of welding-fume measurements have been assembled, we could not identify results on comprehensive side-by-side measurements of particle size-specific Mn concentrations among welders in the literature. We found similar Mn concentrations in the respirable (IQR 8 --320 mg/m 3 ) and inhalable (IQR 10 --340 mg/m 3 ) particle-size fractions of welding fume.…”

“…Exploration of welding databases revealed that airborne exposure is frequently above 200 mg/m 3 . 10 Experimental investigations indicated that due to the low aerodynamic diameter of particles in the welding fume, most of the Mn is respirable. 11 Only few small studies, however, measured Mn in the respirable fraction of the welding fume (for a review, see Hobson et al 12 ).…”

“…12 Another study explored Mn and Fe in weldingfume databases. 10 Similar statistical approaches are needed for estimating exposure-related determinants of systemic exposure to Mn in blood and iron metabolism.…”

Design and Characterization of an Inhalation System of Iron and Manganese Oxide Nanoparticles for Rodent Exposure

“…We chose to focus on the generation of iron (Fe) and manganese (Mn) oxide NP diameter distribution centered on 20-25 nm diameters, at concentrations of 10 7 -10 8 NP/cm 3 . This is representative of the occupational exposure of welders (Li, 2004;Flynn and Susi 2009;SimonDeckerset al 2013;Antonini et al 2011;Andujaret al 2014;Park et al 2014).…”