Screening for toxic industrial chemicals using semipermeable membrane devices with rapid toxicity assays

A time-integrated sampling device interfaced with two toxicity-based assays is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethylsulfoxide (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 concentrated (i.e., 10% of the 24 h maximum) in as little as 10 min and was concentrated by a factor of over 200 for a 24 h exposure time as measured using both mass and toxicity assays. The effect of each of the TICs on the Microtox bacterial luminescence assay and IQ-Tox Daphnia magna fluorescence assay was determined both from a direct assay and a vapor accumulation assay using SPMDs. Microtox EC50 values (concentrations yielding 50% inhibition) were determined for each of the TICs analyzed. The rank order of the Microtox EC50 values for each of the compounds measured by direct dilution of the TICs into assay buffer was similar but not identical to the Apparent (App) EC50 values determined from the vapor accumulation assay. The ratios of the EC50 to the AppEC50 values were used to calculate apparent toxicity-derived concentration factors (i.e., the toxicity equivalents of compound that concentrate from vapor into the SPMD). EC50 values for the IQ-Tox assay as measured using a 90 min fluorescence assay were, in most cases, similar but not identical to the Microtox EC50 values for individual compounds.