Workplace emission factors for hexavalent chromium plating.
Conroy-LM; Wadden-RA; Scheff-PA; Franke-JE; Keil-CB
Appl Occup Environ Hyg 1995 Jul; 10(7):620-627
A methodology for determining workroom hexavalent-chromium (18540299) (Cr+6) emissions during chromium plating processes was described. The approach was based on collecting area particulate samples at various distances from a Cr+6 emission source along with measurements of the ventilation rate. The samples were analyzed for Cr+6 by proton induced X-ray emission spectroscopy. These data were transformed to emission rates and factors using a multipoint diffusion mass balance model in conjunction with variables that were specific to the geometry and patterns of work in the workspace. The method was applied to determining Cr+6 emission rates and factors in an electroplating shop where aluminum pistons were plated with chromium (7440473). Hourly Cr+6 emissions measured 49.6, 137, and 249 inches from the piston line varied from 1.09 to 8.59, 0.35 to 4.71, and 0.20 to 3.32 micrograms per cubic meter (microg/m3), respectively. All were below the American Conference of Governmental Industrial Hygienists Cr+6 standard of 50microg/m3. Baseline Cr+6 emissions averaged around 0.04 to 0.31microg/m3. Total chromium emissions were significantly related to the ampere hours (A- hr) of chromium plating. This yielded a Cr+6 emission factor of 0.0805 milligram per A-hr as determined from a least square fit of the data. When the emission rate and factors were compared with the ventilation measurements, this indicated that the ventilation hoods were operating at an efficiency of greater than 99%. The authors conclude that determining emission rates in this manner provides a more systematic basis for evaluating emission control in the workplace.
NIOSH-Publication; NIOSH-Grant; Control-technology; Hexavalent-chromium-compounds; Occupational-exposure; Industrial-hygiene; Ventilation-systems; Airborne-particles; Workplace-studies
Environmtl/occupatnl Hlth Scis University of Illinois PO Box 6998 Chicago, IL 60680
Applied Occupational and Environmental Hygiene
University of Illinois at Chicago, Chicago, Illinois