No abstract

A study was conducted to isolate and characterize monoterpene-degrading microorganisms and apply them to a biofiltration unit for use in degrading high levels of alpha-pinene. Soil from a monoterpene-contaminated site was used with enrichment culture techniques to recover a consortium of bacteria able to utilize alpha-pinene as the sole source of carbon and energy. The Biolog system was utilized to identify the bacteria as Pseudomonas fluorescens and Alcaligenes xylosoxidans. Aerobic growth and biodegradation studies confirmed that rapid growth and biodegradation were being achieved with alpha-pinene. Complete degradation of alpha-pinene was achieved in 36 h with a maximum rate of degradation of 3.9 mg/L/h. The microorganisms were placed in a biofiltration column and demonstrated good removal of alpha-pinene from an air stream at concentrations averaging 295 ppmv. A nitrogen test was performed and confirmed that the removal of alpha-pinene was due to biological activity. Given the ability of these microorganisms to utilize high levels of alpha-pinene, they will be used in a coupled treatment system using a physical/chemical adsorption/desorption unit coupled to a biofiltration column. Often, biofiltration studies are performed using much lower levels of analyte in the influent air stream. However, the ability of these microorganisms to utilize higher levels of compounds expands the capabilities for future coupled biofiltration systems. During future studies, high flow rates with low levels of analyte will be concentrated so that a higher analyte concentration and lower flow rate can be utilized with the biofilter.http://link.springer-ny. com/link/service/journals/00244/bibs/37n2p151.html

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.

Abstract-A study 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.

The effectiveness of biofilters in removing volatile organic compounds (VOCs) in complex mixtures is often difficult to evaluate due to the presence of numerous unknown compounds. A study was undertaken to determine if a simple, accurate, and useful method could be developed for the quantification of complex mixtures of VOCs. The study compared results from an external standard calibration with several primary components, an internal standard calibration with deuterated ethylbenzene (EB-d10), and an external total hydrocarbon calibration. The EB-d10 internal standard calibration resulted in quantifications of both area sum and individual compounds in the VOC stream which were within 12% of the two external calibrations. This technique allows technicians to monitor the concentrations of all analytes individually and as a group without complicated calibration techniques or preparation of multi-component standards. Finally, this method has proved useful in the quantification of air VOC samples which were incorporated into a commercially available toxicity assay system.