The utilization of conifer species to detect chlorinated atmospheric contaminants at a wood-preserving waste bioremediation facility

Abstract

This study focused on the development of a passive in situ sampling method for the detection and assessment of atmospheric contamination. Conifer needles were collected adjacent to a wood-preserving waste bioremediation facility and at a background area in a National Park. The samples were solvent extracted and bioassayed in the Salmonella microsome assay and the E . coli prophage induction assay for detection of mutagenicity. Splits of several samples were analyzed for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs). Other samples were extracted and analyzed for pentachlorophenol. Results of the Salmonella bioassay did not indicate mutagenic activity in any of the samples collected on-site or off-site. Two samples collected on-site were weakly mutagenic in the Ej. coli assay (an assay that is more sensitive to chlorinated organics than the Salmonella bioassay). Splits of three on-site and two off-site samples were all found to contain PCDDs/PCDFs. Concentration of PCDDs/PCDFs decreased with distance southeast of the source of contamination. Concentrations of PCDDs/PCDFs in the background samples were as much as 186 times less than the concentration found on-site. The very low PCDD/PCDF concentrations detected in background samples were lower than concentrations of PCDDs/PCDFs detected in European background samples, indicating a relatively clean area for background sample collection. The chemical analyses of other samples detected pentachlorophenol in the two samples collected on-site but none in the sample collected in the background area. The results indicate that the Salmonella assay did not respond to the chlorinated contaminants and the E. coli assay did weakly respond. The maximum E^_ coli response was to a sample collected on-site. The chemical analysis was a good tool for detecting contaminants on-site and off-site, with both the PCDDS/PCDFs and the pentachlorophenol. Toxic equivalency factors were calculated for each sample analyzed for PCDD/PCDF concentrations. Sums of TEFs (TEQs) were used to compare samples with others collected on-site and at the background area. Thus the use of conifer species proved to be a good method of detecting atmospheric contaminants at a wood-preserving bioremediation facility.