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United States Department of Agriculture

Agricultural Research Service

Research Project: DIOXINS AND OTHER ENVIRONMENTAL CONTAMINANTS IN FOOD

Location: Animal Metabolism-Agricultural Chemicals Research

Title: Pcdd and Pcdf Emissions from Simulated Sugarcane Field Burning

Authors
item Gullett, Brian - US EPA
item Touati, Abderrahmane - US EPA
item Huwe, Janice
item Hakk, Heldur

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2006
Publication Date: October 27, 2006
Citation: Gullett, B.K., Touati, A., Huwe, J.K., Hakk, H. 2006. PCDD and PCDF emissions from simulated sugarcane field burning. Environmental Science and Technology. 40(20):6228-6234.

Interpretive Summary: Combustion has long been known to be an important contributor to polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs)in the environment. However, appropriate chlorine sources need to be present in order for PCDDs and PCDFs to be formed. Coastal areas may contain enough chorine from sea spray to contribute to PCDD/PCDF formation during field burning, but little published data exists. Therefore, emissions from simulated sugarcane field burns were sampled and analyzed for PCDDs and PCDFs from Hawaii and Florida. They were burned in a manner simulating the practice of preharvest field burning. Eight composite burn tests consisting of kg amounts of biomass were conducted. The two sources of sugarcane had distinctive emission levels, as did tests on separate seasonal gatherings of Florida sugarcane. The average emissions of two tests of Hawaii sugarcane was 50 times higher and for two gatherings of Florida sugarcane was 5 times higher than emission values commonly attributed to biomass combustion. Application of these observed emissions to the known range of U.S. sugarcane fields burned suggests this may be a relatively minor source of PCDDs and PCDFs in the U.S. national inventory. The limited sample size and high standard deviations of results make this conclusion tenuous, and bias towards lab simulations compared to field data may still exist.

Technical Abstract: The emissions from simulated sugarcane (Saccharum officinarum) field burns were sampled and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs). Sugarcane leaves from Hawaii and Florida were burned in a manner simulating the natural physical dimensions and biomass density found during the practice of preharvest field burning. Eight composite burn tests consisting of 3-33 kg of biomass were conducted, some with replicate samplers. Emission factor calculations using sampled concentration and measured mass loss compared well to rigorous carbon balance methods commonly used in field sampling. The two sources of sugarcane had distinctive emission levels, as did tests on separate seasonal gatherings of Florida sugarcane. The average emission factor of two tests of Hawaii sugarcane was 253 ng toxic equivalents (TEQ)/kg carbon burned (ng TEQ/kgCb) (rsd 16%), and for two gatherings of Florida sugarcane was 25 ng TEQ/kgCb (N = 4, rsd 50%) and 5 ng TEQ/kgCb (N = 2, rsd 91%). The Hawaii sugarcane, as well as most of the Florida sugarcane, had emission values which were above the value of 5 ng TEQ/kgCb commonly attributed to biomass combustion. Application of this emission factor range to the amount of U.S. sugarcane fields burned suggests this practice may be a relatively minor source of PCDDs and PCDFs in the U.S. national inventory, but the limited sample size and range of results make this conclusion tenuous.

Last Modified: 7/24/2014
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