Dose-response for occupational styrene exposures.
Rappaport-SM; Yager-JW; Smith-AH
NIOSH 1989 Dec; :1-12
This study investigated the linkages between exposure, uptake, and genotoxic response resulting from occupational exposure to styrene in the reinforced-plastics industry. A longitudinal assessment of exposure was completed in which 48 subjects were monitored in a single facility where fiberglass boats were manufactured. The primary purpose of the study was to accurately estimate the airborne exposure and uptake of each individual in the cohort for comparison with several indices of genotoxic response measured in blood samples, i.e., SCEs in peripheral lymphocytes and the adducts, SO-Hb and SO-DNA. This would allow exposure-dose-response relationships to be established for styrene and for SO arising from metabolism of styrene in vivo. A secondary objective was to correlate the above indices of styrene uptake and genotoxicity with each other in a common pool of samples where exposure had been carefully documented. Each individual's airborne exposure was measured 7 times (shift-long sampling), his/her blood was collected 4 times, and his/her exhaled air was collected up to 25 times over a l2-month period. Exposures were measured with passive monitors employing coconut carbon. Measurement of styrene in the exhaled air employed a new device which collects styrene from 3 L of mixed exhaled air in a tube containing 200 mg of coconut carbon. Both types of samples were analyzed by solvent desorption/gas chromatography. Blood styrene was measured via the head space technique using standard addition and gas chromatography. SCEs were measured by the standard method. SO-DNA is measured by a modification of the post-labeling technique. A new technique has been developed for measuring SO-Hb, which takes advantage of a metal catalyst (Raney-nickel) to selectively cleave SO-cysteine adducts of Hb to yield 1- and 2-pheny1ethanol, which are subsequently derivitized and measured by gas chromatography with electron-capture detection. A separate aspect of the investigation concerned the application of a pharmacokinetic model for styrene, derived under constant-exposure conditions, to the situation typical of occupational exposures where air levels vary greatly over time. The objective of this investigation was to determine the extent to which tissue concentrations of styrene in these compartments were damped compared to the air levels. The input to the pharmacokinetic model was a lognormal1y-distributed, autocorre1ated series of exposure concentrations while the output consisted of the resulting concentrations of styrene in the central and peripheral compartments. Results indicate that the tissue levels of styrene in both compartments would be highly damped relative to the series of short-term exposures.
Styrenes; Occupational-exposure; Genotoxic-effects; Plastics; Plastics-industry; Fiberglass-industry; Airborne-particles; Solvents; Gas-chromatography
Final Grant Report
Other Occupational Concerns
National Institute for Occupational Safety and Health
University of California, Berkeley, California