Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on PCDD/F Emissions from Open Burning of Biomass

To understand the effect of leaf-surface pesticides on emissions of PCDD/F during biomass burns, nine combustion experiments simulating the open burning of biomass were conducted. Needles and branches of <i>Pinus taeda</i> (Loblolly pine) were sprayed with the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) at 1 and 10 times the manufacturer’s recommended application concentration. The biomass was then dried overnight, burned in an open burn test facility, and emission samples were collected, analyzed, and compared against emission samples from burning untreated biomass. Blank tests and analysis of PCDD/F in the raw biomass were also performed. Emission results from burning a water-sprayed control show a ∼20-fold increase in PCDD/F levels above that of the raw biomass alone, implicating combustive formation versus simple volatilization. Results from burns of pine branches sprayed with pesticide showed a statistically significant increase in the PCDD/F TEQ emissions when burning biomass at ten times the recommended pesticide concentration (from 0.22 to 1.14 ng TEQ/kg carbon burned (<i>C</i>_b), both ND = 0). Similarly, a 150-fold increase in the total PCDD/F congener mass (tetra- to octa-chlorinated D/F) above that of the control was observed (from 52 to 7800 ng/kg <i>C</i>_b), confirming combustive formation of PCDD/F from 2,4-D. More replicate testing is needed to evaluate effects at lower pesticide concentrations

Emissions from Small-Scale Burns of Simulated Deployed U.S. Military Waste

U.S. military forces have historically relied on open burning as an expedient method of volume reduction and treatment of solid waste during the conflicts in Afghanistan and Iraq. This study is the first effort to characterize a broad range of pollutants and their emission factors during the burning of military waste and the effects that recycling efforts, namely removing plastics, might have on emissions. Piles of simulated military waste were constructed, burned, and emissions sampled at the U.S. Environmental Protection Agency (EPA) Open Burn Testing Facility (OBTF), Research Triangle Park, NC. Three tests contained polyethylene terephthalate (PET #1 or PET) plastic water bottles and four did not. Emission factors for polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), particulate matter (PM₁₀, PM_2.5), polychlorinated and polybrominated dioxins/furans (PCDD/F and PBDD/F), and criteria pollutants were determined and are contained within. The average PCDD/F emission factors were 270 ng-toxic equivalency (TEQ) per kg carbon burned (ng-TEQ/kg Cb), ranging from 35 to 780 ng-TEQ/kg Cb. Limited testing suggests that targeted removal of plastic water bottles has no apparent effect on reducing pollutants and may even promote increased emissions

Semivolatile and Volatile Organic Compound Emissions from Wood-Fired Hydronic Heaters

Emissions including polychlorinated dibenzo-<i>p</i>-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

Characterization of Carbonaceous Aerosols Emitted from Outdoor Wood Boilers

This study examines the chemical properties of carbonaceous aerosols emitted from different outdoor wood-fired boiler (OWB) technologies including two cord wood heaters, a pellet heater, and a multistage gasifier/combustor. The effect of fuel type [red oak wood (Quercus rubra), white pine wood (Pinus strobes), and red oak with supplementary refuse] on aerosol composition was examined using a classic boiler unit. Aerosol particle emissions were captured using established filter-based sampling methodology and subsequently analyzed using thermal-optical analysis and gas chromatography–mass spectrometry (GC-MS) techniques. GC-MS was coupled with a novel reduced-volume solvent extraction technique for semivolatile organic compound (SVOC) analysis. GC-MS identified 9% w/w of the aerosol mass emitted from the OWBs on average. The OWB aerosols comprised 1–5% w/w levoglucosan, an important molecular marker of cellulose pyrolysis. Organic acid and methoxyphenol SVOC classes showed the highest average concentrations in the OWB aerosol. Polycyclic aromatic hydrocarbons (PAHs) accounted for between 0.1 and 4% w/w of the aerosol mass; PAH emissions from pine wood combustion in the classic OWB were notably high. Each of the original 16 EPA priority PAHs was detected in the OWB PM emissions. Wood combustion in the OWB released significantly more PAH per unit mass of fuel burned than either domestic fireplace or woodstove appliances; although, changes in PAH enrichment (μg/kg aerosol) among domestic wood combustion aerosols was less certain. Of the OWBs tested, the pellet heater showed the lowest SVOC emissions on a mass of fuel burned basis. However, OWB technology did not always significantly influence the SVOC composition of the particle emissions

Characterization of Size-Fractionated Airborne Particles Inside an Electronic Waste Recycling Facility and Acute Toxicity Testing in Mice

Disposal of electronic waste (e-waste) in landfills, incinerators, or at rudimentary recycling sites can lead to the release of toxic chemicals into the environment and increased health risks. Developing e-waste recycling technologies at commercial facilities can reduce the release of toxic chemicals and efficiently recover valuable materials. While these e-waste operations represent a vast improvement over previous approaches, little is known about environmental releases, workplace exposures, and potential health impacts. In this study, airborne particulate matter (PM) was measured at various locations within a modern U.S.-based e-waste recycling facility that utilized mechanical processing. In addition, composite size fractionated PM (coarse, fine and ultrafine) samples were collected, extracted, chemically analyzed, and given by oropharyngeal aspiration to mice or cultured with lung slices for lung toxicity tests. Indoor total PM concentrations measured during the study ranged from 220 to 1200 μg/m³. In general, the coarse PM (2.5–10 μm) was 3–4 times more abundant than fine/ultrafine PM (<2.5 μm). The coarse PM contained higher levels of Ni, Pb, and Zn (up to 6.8 times) compared to the fine (0.1–2.5 μm) and ultrafine (<0.1 μm) PM. Compared to coarse PM measurements from a regional near-roadway study, Pb and Ni were enriched 170 and 20 times, respectively, in the indoor PM, with other significant enrichments (>10 times) observed for Zn and Sb, modest enrichments (>5 times) for Cu and Sr, and minor enrichments (>2 times) for Cr, Cd, Mn, Ca, Fe, and Ba. Negligible enrichment (<2 times) or depletion (<1 time) were observed for Al, Mg, Ti, Si, and V. The coarse PM fraction elicited significant pro-inflammatory responses in the mouse lung at 24 h postexposure compared to the fine and ultrafine PM, and similar toxicity outcomes were observed in the lung slice model. We conclude that exposure to coarse PM from the facility caused substantial inflammation in the mouse lung and enrichment of these metals compared to levels normally present in the ambient PM could be of potential health concern