Design and operation of a popcorn butter flavoring inhalation exposure system.
Goldsmith T; Frazer D; McKinney W; Jones W
American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California. Fairfax, VA: American Industrial Hygiene Association, 2002 Jun; :54
Respiratory disease has been reported in several workers in a microwave popcorn plant. As part of a request to NIOSH to find the cause, extensive medical and environmental measurements were made at the facility. High levels of organic gases and decreased pulmonary function among workers were measured and presumed to be associated with butter flavorings in use at the plant. To test this, an inhalation exposure system was designed and built to deliver butter flavor effluents to small laboratory animals. Butter flavoring contained in a glass vessel was continually stirred and maintained at 55 degrees C with a water bath. Note that these conditions were selected to match conditions of use at the plant. Generator air was conditioned and blown across the heated flavoring, diluted as required, and delivered to the exposure chamber. Direct reading levels of volatile organic compounds were measured within the exposure system. Custom written data acquisition software acquired the VOC signal which was used to adjust mass flow controllers to regulate the concentration of pollutant delivered to the animals. The system was designed for exposing animals to either a pulsed or constant concentration. For pulsed exposure, bulk portions of flavoring were added to the vessel at the beginning and halfway through the experiment. Concentration output exhibited large peaks and valleys which is similar to the exposure experienced by workers who occasionally must check the conditions inside the mixture holding tanks. For constant concentration, a syringe pump provided for adjustable flow of flavoring into the vessel. Control of the concentration at desired levels throughout various experiments was achieved through syringe pump and diluent flow adjustments. Preliminary results of acute inhalation exposures using Sprague-Dawley rats have shown dramatic decreases in breathing and metabolic rates for exposed animals at three exposure levels.
Inhalation-studies; Respiratory-system-disorders; Workers; Organic-compounds; Gases; Laboratory-animals; Animal-studies; Pollutants; Exposure-levels
American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California