Chemical Engineering Department, University of Alicante, Alicante, Spain.
Environ Sci Technol. 2012 Sep 4;46(17):9308-14. doi: 10.1021/es301954t. Epub 2012 Aug 20.
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 Pinus taeda (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 (C(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 C(b)), confirming combustive formation of PCDD/F from 2,4-D. More replicate testing is needed to evaluate effects at lower pesticide concentrations.
为了了解叶面农药对生物质燃烧过程中二噁英/呋喃（PCDD/F）排放的影响，进行了九次模拟生物质露天燃烧的燃烧实验。将 2,4-二氯苯氧乙酸（2,4-D）农药以制造商推荐应用浓度的 1 倍和 10 倍喷洒在火炬松（Loblolly pine）的针叶和树枝上。然后将生物质在一夜之间干燥，在露天燃烧测试设施中燃烧，并收集、分析排放样本，并与未处理生物质燃烧的排放样本进行比较。还对空白测试和原始生物质中的 PCDD/F 进行了分析。水喷洒对照燃烧的排放结果表明，PCDD/F 水平比原始生物质单独燃烧时高出约 20 倍，这表明存在燃烧形成而不是简单的挥发。当以推荐农药浓度的 10 倍燃烧喷洒农药的松树树枝时，PCDD/F TEQ 排放量表现出统计学上的显著增加（从 0.22 到 1.14ng TEQ/kg 燃烧碳（C(b)），均 ND=0）。同样，与对照相比，总 PCDD/F 同系物质量（四氯到八氯 D/F）增加了 150 倍（从 52 到 7800ng/kg C(b)），证实了 2,4-D 形成 PCDD/F 的燃烧形成。需要更多的重复测试来评估较低农药浓度的影响。
