D.J. Wagel

Sources and fate of polychlorinated dibenzodioxins, dibenzofurans and related compounds in human environments

Several of the major incidents resulting in potential human exposures to polychlorinated dibenzodioxins (PCDDs) and/or polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and related compounds which have occurred in the U.S. in recent periods have resulted from improper disposal of hazardous chemical wastes. Prominent examples of such environmental contamination episodes are the Love Canal, into which ton quantities of chlorinated organic compounds containing substantial concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were deposited; numerous sites in the State of Missouri which were contaminated by the dumping of chlorinated organic wastes containing various PCDDs and possibly PCDFs, and PCBs; and the environs of a 2,4-D/2,4,5-T manufacturing plant site in Arkansas, which were contaminated with PCDDs. Environmental assessments of such sites have revealed extensive contamination of soils, waterways, fish and other biological species with these toxic compounds, which in turn could lead to human exposures. Other recently identified sources of PCDDs, PCDFs and related compounds in human environments include stack effluents from municipal refuse incineration, and fires and explosions involving electrical devices containing PCBs and polychlorinated benzenes. Data obtained in assessments of such incidents are presented, and the implications of these findings with respect to the distribution and persistence of PCDDs, PCDFs and related chemicals in the environment and possible effects on humans are discussed.

PCDD/PCDF in the ambient air of a metropolitan area in the U.S.

Abstract The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in the ambient air at several sites in metropolitan Dayton, Ohio have been determined. Total PCDD in the tetra- through octachlorinated groups which were detected in industrialized regions in the present study ranged from 1.6 to 11.2 pg/m3, whereas the corresponding total PCDF ranged from 0.62 to 11.7 pg/m3. No PCDD/PCDF were found in rural regions, typical average detection limits being on the order of 0.02 – 0.17 pg/m3. PCDD/PCDF in the industrialized regions appear to originate from a combination of sources, including municipal solid waste incinerators, motorized vehicles, and a PVC-coated metal incinerator, the latter being a major source of these pollutants. Total PCDD/PCDF congener group patterns, as well as discrete isomer patterns for the various chlorinated groups, in the samples collected at the several sites, were compared. Approximately 50% of the total chlorinated congeners of PCDD/PCDF in the ambient air samples collected consist of 2,3,7,8-chlorine substituted isomers.

Laboratory and field tests to demonstrate the efficacy of KPEG reagent for detoxification of hazardous wastes containing polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) and soils contaminated with such chemical wastes

Abstract A chemical reagent (KPEG) produced by reacting solid potassium hydroxide with a polyethylene glycol formulation has been shown, in both laboratory and field tests, to be effective for dechlorinating polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) present in two different hazardous wastes and in soils contaminated with these.

Assessments of ambient air sampling techniques for collecting airborne polyhalogenated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and biphenyls (PCB)

Abstract An ambient air sampler employing a filter and a polyurethane foam/XAD-2 cartridge effectively traps and retains the 2,3,7,8-chlorine substituted dibenzo-p-dioxin and dibenzofuran isomers, as well as 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) and 2,3,7,8-tetrabromodibenzofuran (TBDF), and permits quantitation of these isomers in ambient air at concentrations lower than 1 pg/m 3 .

Results of comparative evaluations of various fused silica capillary GC columns for retention of tetrachlorinated dibenzo-p-dioxins and dibenzofurans

Abstract Absolute retention times for all twenty-two tetrachlorinated dibenzo-p-dioxin isomers and all thirty-eight tetra-chlorinated dibenzofuran isomers have been measured for several fused silica capillary GC columns coated with a variety of commercially available stationary phases. Data are reported for columns coated with 50% Cyano-propyl, 25% Phenylmethyl silicone (DB-225), 50% Trifluro-propylsilicone (SP-2401), and Polyethyleneglycol (DB-WAX). A two phase loading column for separation of 2,3,7,8-TCDF is presented.

Dechlorination of PCDD and PCDF sorbed on activated carbon using the KPEG reagent

Abstract A chemical reagent (KPEG) produced by reacting potassium hydroxide with a polyethylene glycol formulation, has been employed to effectively dechlorinate polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) sorbed on spent activated carbon which had been utilized for cleanup of aqueous leachate from a hazardous waste landfill. Batch reactor studies conducted in the laboratory demonstrated that direct treatment of contaminated carbon with KPEG for periods up to eight hours at temperatures ranging from 100–145°C, resulted in complete dechlorination of more than 95% of most of the tetra-through octachlorinated CDD/CDF congeners. The direct treatment process was observed to be more effective when water and other low-boiling organic components were removed from the reaction mixture by distillation, either prior to or during the treatment process. In separate experiments, PCDD/PCDF were extracted from samples of the contaminated carbon, and the extract was then treated with KPEG. With this procedure, greater than 99% destruction of all tetra-through octachlorinated PCDD/PCDF was achieved in four hours or less.

Improved separations procedures for isolating 2,3,7,8-TCDD and 2,3,7,8-TCDF from chemically-complex aqueous and solid sample martrices and for definitive quantitation of these isomers at ppq to ppt concentrations

Abstract An analytical procedure has been developed and validated for quantitatively measuring 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) present at parts-per-trillion (ppt) to parts-per-quadrillion (ppq) concentrations in various paper manufacturing process and waste water samples.

Determination of dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) in paper pulp mill defoamer additives and in paper pulp samples

Abstract An analytical procedure has been developed for quantitatively measuring dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) present at part-per-billion levels in paper mill defoamers and paper pulp using gas chromatography coupled with either low resolution mass spectrometry (GC-LRMS) or high resolution mass spectrometry (GC-HRMS).