“Wildfire charcoal is ubiquitous in many landscapes around the world and a comprehensive understanding of its effects on the climate system, ecosystem function, and environmental health is therefore fundamental.”
Image Credit: Avula Kodanda Raghuveer/Shutterstock.com
Wildfires are a natural process that occur in ecosystems to spur periods of regrowth and regeneration. However, with an increased human influence on the rising frequency of anthropogenically and naturally caused wildfires, much remains to be studied about the environmental implications of these events. Specifically, wildfires produce the material charcoal, a valuable energy source that can be found in a diverse array of landscapes and has an effect on climate systems and overall ecosystem health. Charcoal holds this influence within the natural environment partly because of its role as a source of environmentally persistent free radicals (EPFRs).
Volatile in nature, free radicals are precursors to reactive elemental forms like oxygen that pose a potential threat to the environment. EPFRs have been associated with negative consequences on natural systems. From adverse effects on a minuscule scale to bacteria and individual cell functioning as well as disruption of entire processes like effective plant growth and development, EPFRs pose a potential threat to living systems (including humans).
虽然先前的研究集中在木炭作为污染物及其在破坏自然营养周期中的作用，但对木炭是环境持续的自由基的来源知之甚少。来自奥地利，西班牙和英国大学的欧洲研究人员团队着手研究EPFR，特别关注野火木炭中其集中度和稳定寿命。
Measuring the Levels and Stability of Free Radicals in Wildfire Charcoal Samples
研究小组分析了60种从10个不同野火场所收集的野火木炭样品，以确保在研究中可以在各种生态系统中得出结论。例如，样品起源于森林，灌木丛和草原在内的生态系统，包括热带，亚热带和温带等各种气候。
收集后，研究小组随后使用一系列物理和化学分析方法对野火木炭进行了表征。具体而言，使用X频段Bruker Elexsys-II E500 ESR光谱仪（Bruker Biospin GmbH）对样品进行ESR光谱法，调制频率为100 kHz，微波炉频率为9.8 GHz。使用Bruker Win ESR采集软件进行了进一步的测量和计算。然后分析数据。
这项研究发现，野火木炭中的EPFR浓度高。此外，研究发现，分析样品中的EPFR水平与木炭中还记录的碳量正相关。
Not only did this investigation reveal information about the amount of EPFRs in wildfire charcoals, but also provided insight into the nature of the EPFRs. The scientist group concluded that EPFRs in wildfire charcoal remain stable for years. During their experiments, they observed miniscule reductions in EPFR concentrations over four years after a wildfire event with a slightly higher decrease during the fifth year following a fire and formation of free radical filled charcoals.
The high concentrations coupled with the high stability of EPFRs in natural ecosystems pose significant environmental implications. Should charcoal and EPFRs within it reach and pollute water sources, the EPFRs could metamorphose into highly unstable and toxic forms.
但是，研究人员认为，进一步的研究是必要的，以准确理解和得出关于环境风险野火木炭EPFR姿势的程度和强度的结论。尤其是随着自然和人类引起的原因的全球条件转移和增加的野火，检查木炭中的EPFR对于理解环境动态至关重要。
电子旋转共振（ESR）或称为电子顺磁共振（EPR）对在任何物质中检测未配对的电子旋转非常敏感。有机自由基携带这种未配对的电子，并参与了各种过程，从聚合物降解的食物和化妆品的氧化衰老和原油中的沥青质检测到此处所述，在野火碎片中包括木炭。
布鲁克（Bruker）独特的EPR仪器和解决方案投资组合范围从按钮质量控制工具到灵敏度增强的研究仪器。
参考
- Sigmund, G., Santín, C., Pignitter, M. et al. Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years. Commun Earth Environ 2, 68 (2021).https://doi.org/10.1038/s43247-021-00138-2
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