LEAD, CHROMIUM, AND CADMIUM EMISSION FACTORS DURING ABRASIVE BLASTINGOPERATIONS BY BRIDGE PAINTERS

Work space airborne concentrations of lead, chromium, and cadmium were measured during abrasive blasting by bridge painters for the determin ation of emission rates. The operation used com pressed air to blast s teel grit at steel or metal surfaces, removing lead-based paint. It wa s enclosed with plastic tarpaulins to prevent the release of lead- and chromium-laden dust. Consequently, workers were at increased risk fro m exposure by inhalation or ingestion. Area samples were collected in 13 contained work areas on a 4-leaf bridge and adjacent viaduct while blasting was performed Enclosure volume and exhaust airflow rare were measured for each containment area. Work space airborne concentrations ranged from 196-31 410 mu g/m(3) for lead, 1-657 mu g/m(3) for chromi um, and 1-19 mu g/m(3) for cadmium. Mass balance models were used to c alculate emission rates and emission factors using the measured area c oncentrations. Average emission factors on the bridge were 20 400 mg/m (2) for lead, 75 mg/m(2) for chromium, and 16 mg/m(2) for cadmium; and on the viaduct were 8790 mg/m(2) for lead, 568 mg/m(2) for chromium, and 2.0 mg/m(2) for cadmium. These values were validated using estimat es of total paint volume and composition on the structure and total wa ste generation. All estimates were within 50% of each other except chr omium estimates for the bridge. The emission factors allow prediction of work space airborne concentrations during similar operations and ar e a first step in the design and implementation of control measures.