title: Manganese and welding fume exposure and control in construction.
abstract: Overexposure to welding fume constituents, particularly manganese, is of concern in the construction industry due to the prevalence of welding and the scarcity of engineering controls. The control effectiveness of a commercially available portable local exhaust ventilation (LEV) unit was assessed. It consisted of a portable vacuum and a small bell-shaped hood connected by a flexible 2 inch (50.8 mm) diameter hose, in both experimental and field settings. The experimental testing was done in a semienclosed booth at a pipefitter training facility. Five paired trials of LEV control vs. no control, each approximately 1 hr in duration and conducted during two successive welds of 6 inch (152.4 mm) diameter carbon steel pipe were run in random order. Breathing zone samples were collected outside the welding hood during each trial. In the field scenario, full-shift breathing zone samples were collected from two pipefitters welding carbon steel pipe for a chiller installation on a commercial construction project. Eight days of full-shift sampling were conducted on both workers (n = 16), and the LEV was used by one of the two workers on an alternating basis for 7 of the days. All samples were collected with personal sample pumps calibrated at 2 L/min. Filter cassettes were analyzed for total particulate and manganese concentration by a certified laboratory. In the experimental setting, use of the portable LEV resulted in a 75% reduction in manganese exposure (mean 13 microg/m(3) vs. 51 microg/m(3); p < 0.05) and a 60% reduction in total particulate (mean 0.74 mg/m(3) vs. 1.83 mg/m(3); p < 0.05). In the field setting, LEV use resulted in a 53% reduction in manganese exposure (geometric mean 46 microg/m(3) vs. 97 microg/m(3); p < 0.05) but only a 10% reduction in total particulate (geometric mean 4.5 mg/m(3) vs. 5.0 mg/m(3); p > 0.05). These results demonstrate that LEV use can reduce manganese exposure associated with welding tasks in construction.
authors.affiliation: Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Meeker
authors.forename: Pam
authors.initials: P
authors.lastname: Susi
authors.forename: Michael R
authors.initials: MR
authors.lastname: Flynn
mesh_terms: D000336:Aerosols / Q000032:analysis; D000395:Air Pollutants, Occupational / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation*; D005160:Facility Design and Construction; D006801:Humans; D008345:Manganese / Q000032:analysis*; D016273:Occupational Exposure / Q000032:analysis* / Q000517:prevention & control / Q000592:standards; D012906:Smoke / Q000032:analysis*; D014691:Ventilation; D014896:Welding
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D012906:Smoke; D008345:Manganese