Characterization of emissions from burning methyl-bromide-treated crop biomass

ABSTRACT

Alfalfa hay that was grown on a field treated with a methyl bromide and chloropicrin pesticide (at a 98/2 weight ratio) resulted in animal sickness, posing a disposal issue for the harvested feed. In consideration of disposal options, emissions and residues from burning treated and untreated alfalfa hay were sampled and analyzed to provide data for an assessment of potential health and environmental effects. Treated alfalfa hay was tested in parallel with untreated alfalfa in a controlled laboratory combustion facility. Results showed that about half of the bromine and chlorine in the treated hay was emitted and the remaining was retained in the ash. The alfalfa hay burned poorly, with modified combustion efficiencies, the ratio of CO₂ to CO + CO₂, below 0.89. The emission factor for PM_2.5 was statistically higher for the untreated versus treated alfalfa but the PAHs were doubled in the treated alfalfa. The treated alfalfa had significantly more emissions of polychorinated dibenzodioxin/dibenzofuran than the untreated alfalfa by a factor of 10, but less polybrominated dibenzodioxin/dibenzofuran. The high Br concentration in the treated alfalfa biomass may have resulted in formation and emission of mixed halogen compounds which were unable to be analyzed for lack of standards. Comparison of volatile organic compound emissions were unremarkable with the exception of MeBr where emissions from the treated alfalfa were over 300 times higher than the untreated biomass. The potential complications due to emissions and permitting of an open burn or contained incinerator left options for landfilling and feedstock blending for handling the treated alfalfa. Implications: This paper illustrates the issues agricultural managers must deal with concerning the combustive disposal of contaminated crops. A method is presented whereby combustion of contaminated crops can be assessed for their suitability for disposal by open air or enclosed burning.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data used in the writing of this manuscript is available at the U.S. Environmental Protection Agency’s Environmental Dataset Gateway (https://edg.epa.gov).

Supplemental information

Additional information on PM, VOCs, and PXDD/PXDF are included.

Supplemental Material

Supplemental data for this paper can be accessed on the publisher’s website.

Additional information

Funding

Funding for this work was provided by the U.S. EPA through the Regional and Applied Research (RARE) program with EPA Region 10 and the Office of Research and Development. Ingrid George conducted the carbonyl analyses.The views expressed in this article are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection agency

Notes on contributors

Johanna Aurell

Johanna Aurell is a Principal Environmental Scientist with expertise in sampling and characterizing emissions from open and commercial combustion sources using unmanned aerial systems.

Brian Gullett

Brian Gullett is a Scientific and Technical Professional (ST level), Senior Research Engineer with the U.S. Environmental Protection Agency’s Office of Research and Development (ORD), located in Research Triangle Park, North Carolina. His research has investigated formation mechanisms of chlorinated dioxins and furans in combustion systems, as well as other organohalogen compounds. His current work involves development of emission samplers for use on unmanned aircraft systems to characterize hazardous pollutants from open air combustion and detonation processes.

Dirk Helder

Dirk Helder worked for ten years at the U.S. Environmental Protection Agency’s Office of Pesticide Programs developing risk mitigation strategies to ensure pesticides can be safely used while also protecting human health and the environment. He focused on protecting pesticide applicators and farmworkers from the harmful effects of pesticide thru more effective and understandable pesticide label language. He has spent the past fifteen years in EPA Region 10, in the Enforcement and Compliance Assurance Division working primarily with Northwest state departments of agriculture on water quality, ESA, pesticide applicator and farmworker issues. The opportunity to work more closely with field staff from the states and have the chance to interface between EPA and farmer workers and pesticide applicators has been his primary focus.

Robert Elleman

Robert Elleman works for U.S. Environmental Protection Agency Region 10 (Alaska, Idaho, Oregon, Washington) as the science research liaison. His research has focused on airborne particulate matter in the U.S. Pacific Northwest and Alaska to understand the emissions, transport, short-term forecasting, and control technologies of biomass burning.