Evaluating wipe sampling parameters to assess method performance and data confidence during remediation of hazardous pesticide misuse chemicals on indoor materials.

Pesticide misuse incidents are reported worldwide each year. The potential exposure to pesticides creates a concern for occupants in affected homes, apartments, and other occupied buildings. Pesticides that are improperly applied within these locations may require remediation prior to reoccupation. Incident response personnel rely heavily on data from sampling results to identify residue levels and determine when site remediation is complete. Surface wipe samples are often collected for this purpose. Therefore, it is important to ensure sampling and analysis procedures are well established for the contaminants of concern, particularly for wipe sampling variables that can affect analysis results. This investigation evaluated the effects of surface wipe media, wipe wetting solvents, pesticide concentrations effects, composite sampling, surface types, and pesticide formulation effects on analysis results for fipronil, permethrin, and deltamethrin. Tested surface types included galvanized steel, vinyl tile, and plywood. Wipe media included pre-packaged, sterile cotton gauze, pre-cleaned cotton twill, and a pre-packaged, pre-wetted wipes. Surface recovery results are reported for commercially available fipronil formulations and compared to technical grade fipronil solutions. Fipronil recoveries were 92-107 % for twill wipes, 81-98 % for cotton gauze wipes, and 79 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. Permethrin recoveries were 83-116 % for twill wipes, 66-94 % for cotton gauze wipes, and 73 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. Deltamethrin recoveries were 67-88 % for twill wipes, 55-71 % for cotton gauze wipes, and 63 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. The data collected in this study can inform surface wipe sampling methods and potentially assist in obtaining more accurate sampling data associated with pesticide misuse incidents involving the target analytes.

Remediating Indoor Pesticide Contamination from Improper Pest Control Treatments: Persistence and Decontamination Studies.

The improper and excessive use of pesticides in indoor environments can result in adverse human health effects, sometimes necessitating decontamination of residential or commercial buildings. A lack of information on effective approaches to remediate pesticide residues prompted the decontamination and persistence studies described in this study. Decontamination studies evaluated the effectiveness of liquid-based surface decontaminants against pesticides on indoor surfaces. Building materials were contaminated with 25-2,400 µg/100cm2 of the pesticides malathion, carbaryl, fipronil, deltamethrin, and permethrin. Decontaminants included both off-the-shelf and specialized solutions representing various chemistries. Pesticides included in this study were found to be highly persistent in a dark indoor environment with surface concentrations virtually unchanged after 140 days. Indoor light conditions degraded some of the pesticides, but estimated half-lives exceeded the study period. Decontamination efficacy results indicated that the application of household bleach or a hydrogen peroxide-based decontaminant offered the highest efficacy, reducing malathion, fipronil, and deltamethrin by >94-99% on some surfaces. Bleach effectively degraded permethrin (>94%), but not carbaryl (<70%) while the hydrogen peroxide containing products degraded carbaryl (>71-99%) but not permethrin (<54%). These results will inform responders, the general public and public health officials on potential decontamination solutions to remediate indoor surfaces.

The impact of wipe sampling variables on method performance associated with indoor pesticide misuse and highly contaminated areas.

Pesticide misuse incidents in residential indoor areas are typically associated with misapplications that are inconsistent with the label directions of the product. Surface wipe sampling and analysis procedures are relied upon to evaluate the extent of indoor contamination and the remediation efforts successfully. In general, surface wipe sampling procedures are widely varied, which can complicate the comparison of the results and data interpretation. Wipe sampling parameters were studied for the insecticides malathion and carbaryl. The parameters evaluated include wipe media, wetting solvents, composite sampling, surface concentration, and the influence of differing product formulations. Porous and nonporous surfaces tested include vinyl tile, plywood and painted drywall (porous/permeable) and stainless steel and glass (nonporous/impermeable). Specific wipe materials included pre-packaged sterile-cotton gauze, pre-cleaned cotton twill, cotton balls, and a pre-packaged, pre-wetted wipe. Commercially available insecticide formulations were tested, and the results were compared to surfaces fortified with neat analytes to determine surface recovery results (efficiency). A sampling procedure to measure pesticide residues was developed, and variables associated with the sampling methods were evaluated to clarify how estimations of surface residues are impacted. Malathion recoveries were 73-86% for twill and pre-wetted, pre-packaged isopropanol wipes on nonporous materials. Malathion formulations ranged from 78 to 124% for pre-wetted, pre-packaged isopropanol wipes and cotton gauze wipes on nonporous materials. Carbaryl and carbaryl formulation recoveries were 82-115% and 77-110%, respectively, on nonporous surfaces for all tested wipe materials. While not every wipe sampling variable could be tested, the collected information from this study may be useful and applied to sampling plans for classes of chemicals with similar physicochemical properties.

Characterization of emissions and residues from simulations of the Deepwater Horizon surface oil burns.

The surface oil burns conducted by the U.S. Coast Guard from April to July 2010 during the Deepwater Horizon disaster in the Gulf of Mexico were simulated by small scale burns to characterize the pollutants, determine emission factors, and gather particulate matter for subsequent toxicity testing. A representative crude oil was burned in ocean-salinity seawater, and emissions were collected from the plume by means of a crane-suspended sampling platform. Emissions included particulate matter, aromatic hydrocarbons, polychlorinated dibenzodioxins/dibenzofurans, elements, and others, the sum of which accounted for over 92% by mass of the combustion products. The unburned oil mass was 29% of the original crude oil mass, significantly higher than typically reported. Analysis of alkanes, elements, and PAHs in the floating residual oil and water accounted for over 51% of the gathered mass. These emission factors, along with toxicity data, will be important toward examining impacts of future spill burning operations.

Emissions from prescribed burning of timber slash piles in Oregon.

Emissions from burning piles of post-harvest timber slash (Douglas fir) in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether- controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5), black carbon, ultraviolet absorbing PM, elemental/organic carbon, filter-based metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins/dibenzofurans (PCDD/PCDF), and volatile organic compounds (VOCs) were sampled to determine emission factors, the amount of pollutant formed per amount of biomass burned. The effect on emissions from covering the piles with polyethylene (PE) sheets to prevent fuel wetting versus uncovered piles was also determined. Results showed that the uncovered ("wet") piles burned with lower combustion efficiency and higher emission factors for VOCs, PM2.5, PCDD/PCDF, and PAHs. Removal of the PE prior to ignition, variation of PE size, and changing PE thickness resulted in no statistical distinction between emissions. Results suggest that dry piles, whether covered with PE or not, exhibited statistically significant lower emissions than wet piles due to better combustion efficiency.

Characterization of Emissions from Liquid Fuel and Propane Open Burns.

The effect of accidental fires are simulated to understand the response of items such as vehicles, fuel tanks, and military ordnance and to remediate the effects through re-design of the items or changes in operational procedures. The comparative combustion emissions of using jet propellant (JP-5) liquid fuel pools or a propane manifold grid to simulate the effects of accidental fires was investigated. A helium-filled tethered aerostat was used to maneuver an instrument package into the open fire plumes to measure CO, CO2, fine particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and elemental/organic/total carbon (EC/OC/TC). The results showed that all emissions except CO2 were significantly higher from JP-5 burns than from propane. The major portion of the PM mass from fires of both fuels was less than 1 µm in diameter and differed in carbon content. The PM2.5 emission factor from JP-5 burns (129 ± 23 g/kg Fuelc) was approximately 150 times higher than the PM2.5 emission factor from propane burns (0.89 ± 0.21 g/kg Fuelc). The PAH emissions as well as some VOCs were more than one hundred times higher for the JP-5 burns than the propane burns. Using the propane test method to study flammability responses, the environmental impact of PM2.5, PAHs, and VOCs would be reduced by 2300, 700, and 100 times per test, respectively.

A small, lightweight multipollutant sensor system for ground-mobile and aerial emission sampling from open area sources.

Characterizing highly dynamic, transient, and vertically lofted emissions from open area sources poses unique measurement challenges. This study developed and applied a multipollutant sensor and time-integrated sampler system for use on mobile applications such as vehicles, tethered balloons (aerostats) and unmanned aerial vehicles (UAVs) to determine emission factors. The system is particularly applicable to open area sources, such as forest fires, due to its light weight (3.5 kg), compact size (6.75 L), and internal power supply. The sensor system, termed "Kolibri", consists of sensors measuring CO2 and CO, and samplers for particulate matter (PM) and volatile organic compounds (VOCs). The Kolibri is controlled by a microcontroller which can record and transfer data in real time through a radio module. Selection of the sensors was based on laboratory testing for accuracy, response delay and recovery, cross-sensitivity, and precision. The Kolibri was compared against rack-mounted continuous emissions monitoring system (CEMs) and another mobile sampling instrument (the "Flyer") that has been used in over ten open area pollutant sampling events. Our results showed that the time series of CO, CO2, and PM2.5 concentrations measured by the Kolibri agreed well with those from the CEMs and the Flyer, with a laboratory- tested percentage error of 4.9%, 3%, and 5.8%, respectively. The VOC emission factors obtained using the Kolibri were consistent with existing literature values that relate concentration to combustion efficiency. The potential effect of rotor downwash on particle sampling was investigated in an indoor laboratory and the preliminary results suggested that its influence is minimal. Field application of the Kolibri sampling open detonation plumes indicated that the CO and CO2 sensors responded dynamically and their concentrations co-varied with emission transients. The Kolibri system can be applied to various challenging open area scenarios such as fires, lagoons, flares, and landfills.

Characterization of the particulate emissions from the BP Deepwater Horizon surface oil burns.

Sampling of the smoke plumes from the BP Deepwater Horizon surface oil burns led to the unintentional collection of soot particles on the sail of an instrument-bearing, tethered aerostat. This first-ever plume sampling from oil burned at an actual spill provided an opportunistic sample from which to characterize the particles' chemical properties for polycyclic aromatic hydrocarbons (PAHs), organic carbon, elemental carbon, metals, and polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs) and physical properties for size and nanostructure. Thermal-optical analyses indicated that the particulate matter was 93% carbon with 82% being refractory elemental carbon. PAHs accounted for roughly 68µg/g of the PM filter mass and 5mg/kg oil burned, much lower than earlier laboratory based studies. Microscopy indicated that the soot is distinct from more common soot by its aggregate size, primary particle size, and nanostructure. PM-bound metals were largely unremarkable but PCDD/PCDF formation was observed, contrary to other's findings. Levels of lighter PCDD/PCDF and PAH compounds were reduced compared to historical samples, possibly due to volatilization or photo-oxidation.

Aerostat-based sampling of emissions from open burning and open detonation of military ordnance.

Emissions from open detonation (OD), open burning (OB), and static firing (SF) of obsolete military munitions were collected using an aerostat-lofted sampling instrument maneuvered into the plumes with remotely controlled tether winches. PM2.5, PM10, metals, volatile organic compounds (VOCs), energetics, and polyaromatic hydrocarbons (PAHs) were characterized from 121 trials of three different munitions (Composition B (hereafter, "Comp B"), V453, V548), 152 trials of five different propellants (M31A1E1, M26, SPCF, Arc 451, 452A), and 12 trials with static firing of ammonium perchlorate-containing Sparrow rocket motors. Sampling was conducted with operational charge sizes and under open area conditions to determine emission levels representative of actual disposal practices. The successful application of the tethered aerostat and sampling instruments demonstrated the ability to sample for and determine the first ever emission factors for static firing of rocket motors and buried and metal-cased OD, as well as the first measurements of PM2.5 for OB and for surface OD.

Quality control for sampling of PCDD/PCDF emissions from open combustion sources.

Both long duration (>6h) and high temperature (up to 139°C) sampling efforts were conducted using ambient air sampling methods to determine if either high volume throughput or higher than ambient air sampling temperatures resulted in loss of target polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs) from a polyurethane foam (PUF) sorbent. Emissions from open burning of simulated military forward operating base waste were sampled using EPA Method TO-9A for 185 min duration using a filter/PUF/PUF in series combination. After a 54 m(3) sample was collected, the sampler was removed from the combustion source and the second PUF was replaced with a fresh, clean PUF. An additional 6h of ambient air sampling (171 m(3)) was conducted and the second PUF was analyzed to determine if the PCDD/PCDF transferred from the filter and the first PUF. Less than 4.4% of the initial PCDD/PCDF was lost to the second PUF. To assess the potential for blow off of PCDD/PCDF analytes during open air sampling, the mobility of spiked mono- to hepta-PCDD/PCDF standards across a PUF sorbent was evaluated from ambient air temperatures to 145°C with total volumes between 600 L and 2400 L. Lower molecular weight compounds and higher flow amounts increased release of the spiked standards consistent with vapor pressure values. At 600 L total sampled volume, the release temperature for 1% of the tetra-CDD (the lowest chlorinated homologue with a toxic compound) was 87°C; increasing the volume fourfold reduced this temperature to 73°C.

Semivolatile and volatile organic compound emissions from wood-fired hydronic heaters.

Emissions including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polyaromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs), were sampled from different wood-fired hydronic heater (HH) technologies. Four commercially available HH technologies were studied: a single-stage conventional combustor with natural updraft, a three-stage downdraft combustion system, a bottom-fed pellet burner, and a two-stage heater with both a combustion and gasification chamber. The fuel consisted of three wood types (red oak, white pine, and white ash), one hardwood pellet brand, and one fuel mixture containing 95% red oak and 5% residential refuse by weight. The various HHs and fuel combinations were tested in a realistic homeowner fuel-charging scenario. Differences in emission levels were found between HH technologies and fuel types. PCDD/PCDF emissions ranged from 0.004 to 0.098 ng toxic equivalency/MJ(input) and PAHs from 0.49 to 54 mg/MJ(input). The former was increased by the presence of 5% by weight refuse. The white pine fuel had the highest PAH emission factor, while the bottom fed pellet burner had the lowest. The major VOCs emitted were benzene, acetylene, and propylene. The highest emissions of PAHs, VOCs, and PCDDs/PCDFs were observed with the conventional unit, likely due to the rapid changes in combustion conditions effected by the damper opening and closing.

Emissions from open burning of used agricultural pesticide containers.

Emissions from simulated open burning of used agricultural pesticide containers were sampled for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), polycyclic aromatic hydrocarbon compounds (PAHs), and particle matter (PM(10) and PM(2.5)). Clean high density polyethylene (HDPE) containers, containers with trace pesticide, and triple-rinsed containers were burned separately in an open combustion facility and their emissions compared. Two common chlorinated pesticides were used: 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine (atrazine). PCDD/PCDF emission factors ranged from 0.1 to 24ng toxic equivalents (TEQ)/kg C burned with a mean and median of 4.9 and 1.9ng TEQ/kgC burned, respectively. In a limited number of trials, the trace 2,4-D in the HDPE container led to a statistically significant increase in PCDD/PCDF formation compare to all other conditions. Residual atrazine did not lead to more PCDD/PCDF than the unrinsed 2,4-D container. Total (16 compounds) PAH emission factors varied from 1.5 to 6.7mg/kgC burned. These limited data suggest that rinsing the 2,4-D container prior to burning reduces both PCDD/PCDF and PAH emissions. Nine PM(2.5) emission factors ranged from 9 to 35mg/gC burned and ten PM(10) values ranged from 6 to 43mg/gC burned. Neither pesticide appeared to have any effect on PM concentration.

Open burning of household waste: Effect of experimental condition on combustion quality and emission of PCDD, PCDF and PCB.

Open burning for waste disposal is, in many countries, the dominant source of polychlorinated dibenzodioxins, dibenzofurans and biphenyls (PCDD/PCDF/PCB) release to the environment. To generate emission factors for open burning, experimental pile burns of about 100 kg of household waste were conducted with emissions sampling. From these experiments and others conducted by the same authors it is found that less compaction of waste or active mixing during the fire--"stirring"--promotes better combustion (as evidenced by lower CO/CO(2) ratio) and reduces emissions of PCDD/PCDF/PCB; an intuitive but previously undemonstrated result. These experiments also support previous results suggesting PCDD/PCDF/PCB generation in open burning - while still highly variable - tends to be greater in the later (smoldering) phases of burning when the CO/CO(2) ratio increases.

Near-real-time combustion monitoring for PCDD/PCDF indicators by GC-REMPI-TOFMS.

The boiler exit flue gas of a municipal waste combustor was sampled to evaluate an online monitoring system for chlorobenzene congeners as indicators of polychlorinated dibenzodioxin and dibenzofuran (PCDD/PCDF) concentrations. Continuous measurements of chlorobenzene congeners using gas chromatography coupled to a resonance-enhanced multiphoton ionization - time-of-flight mass spectrometry (GC-REMPI-TOFMS) system were compared over 5-min periods with conventional sampling methods for PCDD/PCDF. Three pairs of values were taken every hour over a period of three days to characterize the combustor's response to transient operating conditions (shutdowns and startups). Isolation of specific chlorobenzene congeners from other same-mass compounds was accomplished by using a GC column separator ahead of the REMPI-TOFMS. The 50-fold variation of PCDD/PCDF concentration was paralleled by similar changes in monitored compounds of 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4,5-tetrachlorobenzene. A correlation of R = 0.85 and 0.89 was established between 40 pairs of simultaneous 5-min GC-REMPI-TOFMS measurements of 1,2,4-trichlorobenzene and 5 min conventional sampling and analysis for the TEQ and Total measures of PCDD/PCDF, respectively. The GC-REMPI-TOFMS system can be used to provide frequent measures of correlative PCDD/PCDF concentration thereby allowing for an understanding of measures to minimize PCDD/PCDF formation and develop operational feedback to limit emissions.

Aerostat-lofted instrument and sampling method for determination of emissions from open area sources.

An aerostat-borne instrument and sampling method was developed to characterize air samples from area sources, such as emissions from open burning. The 10 kg battery-powered instrument system, termed "the Flyer", is lofted with a helium-filled aerostat of 4m nominal diameter and maneuvered by means of one or two tethers. The Flyer can be configured variously for continuous CO2 monitoring, batch sampling of semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), black carbon, metals, and PM by size. The samplers are controlled by a trigger circuit to avoid unnecessary dilution from background sampling when not within the source plume. The aerostat/Flyer method was demonstrated by sampling emissions from open burning (OB) and open detonation (OD) of military ordnance. A carbon balance approach was used to derive emission factors that showed excellent agreement with published values.

PBDDs/Fs and PCDDs/Fs in the raw and clean flue gas during steady state and transient operation of a municipal waste combustor.

Concentrations of polybrominated dibenzo-p-dioxins, and -dibenzofurans (PBDDs/Fs) and polychlorinated dibenzo-p-dioxins, and -dibenzofurans (PCDDs/Fs), were determined in the pre- and post-air pollution control system (APCS) flue gas of a municipal waste combustor (MWC). Operational transients of the combustor were found to considerably increase levels of PBDDs/Fs and PCDDs/Fs compared to steady state operation, both for the raw and clean flue gas; ΣPBDDs/Fs increased from 72.7 to 700 pg dscm(-1) in the raw, pre-APCS gas and from 1.45 to 9.53 pg dscm(-1) in the post-APCS flue gas; ΣPCDDs/Fs increased from 240 to 960 ng dscm(-1) in the pre-APCS flue gas, and from 1.52 to 16.0 ng dscm(-1) in the post-APCS flue gas. The homologue profile of PBDDs/Fs and PCDDs/Fs in the raw flue gas (steady state and transients) was dominated by hexa- and octa-isomers, while the clean flue gas homologue profile was enriched with tetra- and penta-isomers. The efficiency of the APCS for PBDD/F and PCDD/F removal was estimated as 98.5% and 98.7%, respectively. The cumulative TEQ(PCDD/F+PBDD/F) from the stack was dominated by PCDD/F: the TEQ of PBDD/F contributed less than 0.1% to total cumulative toxic equivalency of MWC stack emissions.

Effect of moisture, charge size, and chlorine concentration on PCDD/F emissions from simulated open burning of forest biomass.

Loblolly pine (Pinus taeda) was combusted at different charge sizes, fuel moisture, and chlorine content to determine the effect on emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) as well as copollutants CO, PM, and total hydrocarbons. The experiments were performed in an enclosed chamber under conditions simulating open, prescribed burns of forest biomass. Burn progress was monitored through on line measurement of combustion gases and temperature while PCDD/F concentrations were determined by ambient sampling methods. PCDD/F toxic equivalency (TEQ) and total (tetra- to octa-CDD/F) emission factors were independent of charge size (1-10 kg) and moisture content (7-50%). However, the lower chlorinated, mono- to tri-CDD/F compounds were increased by poor combustion conditions: combustion efficiency lower than 0.919 was generally found when the moisture content was higher than 30%. The increase of fuel matrix chlorine from 0.04% to 0.8% using a brine bath resulted in about a 100-fold increase of PCDD/F to about 90 ng TEQ/kg of carbon burned, C(b). These emission factors were linearly dependent on Cl concentration in the biomass. PCDD 2,3,7,8-Cl-substituted congeners and homologue patterns were also influenced by the addition of chlorine resulting in emissions with a higher abundance of the most toxic congeners (TeCDD and PeCDD). When both chlorine and moisture content were increased in the fuel, a simultaneous effect of the two parameters was observed. The increased TEQ values expected from higher Cl concentrations were mitigated by the presence of water, giving MCE = 0.868, promoting formation of mono- to tri-PCDD/F, and lowering the TEQ value. Open burn simulations were used to study PCDD/F formation in different combustion conditions providing a mathematical correlation between PCDD/F emissions and chlorine and moisture content in the fuel.

Toxicity comparison of chlorinated and brominated dibenzo-p-dioxins and dibenzofurans in industrial source samples by HRGC/HRMS and enzyme immunoassay.

Limited information is available on the applicability of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) toxicity assays to their brominated counterparts: polybrominated dibenzo-p-dioxins/furans (PBDDs/Fs). We estimated the toxicity of mixtures of chlorinated, brominated, and mixed bromochloro-dioxins and -furan (PBCDDs/Fs) laboratory standards using a chemically-activated luciferase gene expression cell bioassay (CALUX). The relative effects potency (REP) values obtained were comparable to the World Health Organization (WHO) toxic equivalency factors (TEFs) and in agreement with the concept of additive congener toxicity of mixtures of dioxins and furans. Enzyme immunoassay (EIA)-based toxic equivalents (TEQs), however, showed overestimation for PCDDs/Fs (0-4 orders of magnitudes higher) and underestimation for PBDDs/Fs (0-1 orders of magnitude lower) when compared to high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS)-based TEQ calculation (using WHO TEFs) in samples from an industrial source line. No correlation was found between the EIA and the HRGC/HRMS data, which could be attributed to differences in homologue-specific cross-reactivity responses, sample matrix type, and presence of other compounds competing for antibody binding in the immunoassay.

PCDD/F, PBDD/F, and PBDE emissions from open burning of a residential waste dump.

This work reports on the first known field study determining emission factors for polychlorinated and polybrominated dibenzodioxins/dibenzofurans (P[C/B]DDs/Fs) and polybrominated diphenyl ethers (PBDEs) from open burning of domestic waste. Two burning waste dump sites in Mexico were sampled using high-volume samplers mounted to a mobile sampling boom. Concurrent measurements of CO and CO(2) allowed determination of emission factors via the carbon balance method. PCDD/F emission factors averaged 823 ng toxic equivalency (TEQ)/kg C(burned) (N = 8, 68% relative standard deviation, RSD), a value at least five times higher than those from previous tests with domestic waste burned in barrels and approximately 2000 times higher than those from stacks of modern municipal waste combustors. These emission factors appear to be related to combustion quality, as conditions conducive to smoldering combustion, rather than flaming combustion, resulted in higher emission factors. Emissions of 40 PBDE congeners, likely originating from brominated flame retardants, averaged 724 mug/kg C(burned) (RSD = 96%) and had congener patterns similar to those of reported atmospheric sampling. Emissions of PBDDs/Fs were similar in magnitude to their chlorinated counterparts, averaging 470 ng TEQ/kg C(burned) (RSD = 105%), and may originate as reaction products of PBDE combustion or as thermally desorbed impurities from the PBDE flame retardant.

Same-sample determination of ultratrace levels of polybromodiphenylethers, polybromodibenzo-p-dioxins/furans, and polychlorodibenzo-p-dioxins/furans from combustion flue gas.

The analytical method used for determination of polychlorinated dibenzo-p-dioxins and -furans (PCDDs/Fs) emissions from municipal waste combustors (MWCs) and other stationary sources was modified and validated to additionally allow for analysis of ultratrace levels of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and -furans (PBDDs/Fs) from a common flue gas sample. Potential methodological problems related to physicochemical properties of brominated compounds, including UV- and temperature-induced debromination and degradation, were addressed. The selection of solvents, optimization of extraction time, and adaptation of the cleanup and fractionation steps increased mean recoveries of (13)C(12)-labeled PBDE and PBDD/F isotope dilution surrogates about 18% and 25%, respectively. The customary liquid chromatography isolation of PBDEs and PBDDs/Fs was replaced by optimization of high-resolution gas chromatography to separate target PBDFs (2,3,7,8-Br-substituted) from potentially interfering PBDEs before mass spectroscopic identification. The optimized method allowed quantitative determination of 56 mono- through decabromodiphenylether congeners, 15 congeners of 2,3,7- and 2,3,7,8-Br-substituted tri- to octabromodibenzo-p-dioxins and -furans, and all 210 polychlorinated dibenzo-p-dioxins and -furans present in the flue gas at levels of picogram to microgram per normalized cubic meter.