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VAPOR SAMPLING DEVICE FOR INTERFACE WITH MICROTOX ASSAY FOR SCREENING TOXIC INDUSTRIAL CHEMICALS
Rogers, K R. AND G L. Robertson. VAPOR SAMPLING DEVICE FOR INTERFACE WITH MICROTOX ASSAY FOR SCREENING TOXIC INDUSTRIAL CHEMICALS. Presented at Society of Environmental Toxicology and Chemistry, Portland, OR, Novembr 14-18, 2004.
A time-integrated sampling system interfaced with a toxicity-based assay is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethyl sulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor phase. Uptake kinetics experiments for one of these compounds (acrolein) indicated that it was significantly sequestered (i.e., 10 percent of the 24 hr maximum) in as little as 10 min and was concentrated by a factor of over 200 in 24 hr as measured using both mass and toxicity assays. The effect of each of the TICs on the Microtox bacterial luminescence assay was determined both from a direct assay and a vapor accumulation assay using SPMDs. Microtox EC50 values (concentration yielding 50 percent inhibition) were determined for each of the TICs analyzed and ranged from 0.070 parts per million volume (ppmv) for diketene to 322 ppmv for 1,2-dibromoethane. The rank order of the Microtox EC50 values for each compound measured directly from liquid was similar but not identical to the Apparent (App) EC50 values determined from the vapor accumulation assay. The ratios of the EC50 and the AppEC50 values were used to calculate toxicity-derived Concentration Factors (i.e., the toxicity equivalents of compound that concentrate from vapor into the SPMD). These Concentration Factors ranged from 17 to 5400 and primarily reflected differences in partitioning characteristics between air and DMSO for each compound. Acrolein was chosen as a representative compound for the vapor dilution experiment and it showed a toxicity-based detection limit of 19 mg/m3 which was less than the LD-50 by a factor of 100, but greater than the National Institute for Occupational Safety and Health (NIOSH) 40 hr/week exposure limit also by a factor of 100. Consequently, for acrolein, this system in its current configuration, shows potential for development as an initial screening tool for mid to high acute vapor phase toxicity determinations.
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