Sampling of air streams and incorporation of samples in the Microtox™ toxicity testing system

Abstract

A sudy was conducted to develop a rapid and reliable method for the collection and incorporation of biofiltration air samples containing volatile organic compounds (VOCs) into the Microtox™ toxicity testing system. To date, no method exists for this type of assay. A constant stream of VOCs was generated by air stripping compounds from a complex mixture of petroleum hydrocarbons (PHCs). Samples were collected on coconut charcoal ORBO (Supelco, Inc.) tubes and the VOCs extracted with methylene chloride. The compounds extracted were then solvent exchanged into dimethyl sulfoxide (DMSO) under gaseous nitrogen. The resulting DMSO extract was directly incorporated into the Microtox toxicity testing system. In order to determine the efficiency of the solvent exchange, the VOCs in the DMSO extract were then extracted into hexane and subsequently analyzed using gas chromatography (GC) with a flame ionization detector (FID). It was determined that all but the most volatile VOCs could be effectively transferred from the ORBO tubes to DMSO for Microtox testing. Potential trace amounts of residual methylene chloride in the DMSO extracts showed no adverse effects in the Microtox system when compared to control samples.

Polycyclic Aromatic Hydrocarbon Concentration and Acute Toxicity of Airborne Particulate Matter: Using Microtox as a Toxicity Screening Tool

“…The Microtox bioassay can be used to test liquids or solids. However, to date, only a few studies exist evaluating the toxicity testing of air samples using Microtox (12,15,16). This is because the Microtox system requires all samples to be in aqueous solution for testing purposes.…”