Peatlands are potent landscape sinks of natural and industrial toxic metals and metalloids (TMMs) but the long-term sequestration of TMMs in peatlands is at increasing risk due to climate change enhanced peatland fires. The ability of peatlands to retain TMMs results from a host of interacting hydrological, biological, geomorphological, and chemical feedbacks, which underpin peatland functionality in general. Fire is a transformative force that often disrupts these interactions and feedbacks, leading to the potential release of TMMs to our air, land, and water. Given that wildfire burned area and severity are increasing there is a need for a conceptual understanding of these interactive processes. Prior to a fire, peatland TMM mobility is relatively low, controlled by a peatland's degree of minerotrophy, degradation status, hydrogeomorphic setting and hydroclimate. Incidentally, these peatland characteristics also control the likelihood of peat ignition, creating important feedbacks on the landscape. Following ignition, the temperature and duration of a peat fire plays a critical role in determining the potential TMM emissions to the atmosphere and the post-fire geochemical conditions. We elucidate the varied emission factors of different metals, where emission factors range from 0.2 (Co or Cd) to 300 (Al) mg of metal per kg of particulate matter emitted depending on the specific metal and likely the pre-fire peat metal concentration. Following a peat fire, the geochemical and hydrological changes become increasingly important. For example, post-fire increases in pH play the strongest chemical role in limiting TMM mobilization but concurrent increases in dissolved organic matter aromaticity complicate our understanding of these processes, leading to a critical knowledge gap. At larger spatial scales, peatland and watershed ecohydrological connectivity and peat erosion modulate the release of TMMs to aquatic systems. Yet, the evolution of the ecohydrological connectivity and peat erosion potential as the peatland vegetation and hydrology recover to pre-fire conditions over the course of several to tens of years is governed by the same controls that impact pre-fire TMM mobility. Critically, the uncertainty in evolution trajectories depends on changes in biological, hydrological, climatological, and chemical conditions, limiting our ability to accurately predict these changes under a rapidly changing climate. This extensive and interdisciplinary review guides the development of a conceptual framework and highlights future research needs to better respond to the emerging threat of legacy TMM release from peatland wildfires.

中文翻译：

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泥炭火灾和遗留有毒金属释放：综合生物地球化学和生态水文学概念框架


泥炭地是天然和工业有毒金属和类金属 (TMM) 的有效景观汇，但由于气候变化加剧了泥炭地火灾，泥炭地中 TMM 的长期封存面临着越来越大的风险。泥炭地保留 TMM 的能力源于一系列相互作用的水文、生物、地貌和化学反馈，这些反馈总体上支撑着泥炭地的功能。火是一种变革力量，经常破坏这些相互作用和反馈，导致 TMM 可能释放到我们的空气、土地和水中。鉴于野火烧毁面积和严重程度不断增加，有必要对这些交互过程有一个概念性的理解。在火灾发生之前，泥炭地 TMM 的流动性相对较低，受到泥炭地的矿物营养程度、退化状态、水文地貌环境和水文气候的控制。顺便说一句，这些泥炭地特征也控制着泥炭燃烧的可能性，从而对景观产生重要的反馈。着火后，泥炭火灾的温度和持续时间对于确定向大气中潜在的 TMM 排放和火灾后的地球化学条件起着至关重要的作用。我们阐明了不同金属的不同排放因子，其中排放因子范围为每千克排放颗粒物 0.2（Co 或 Cd）至 300（Al）mg 金属，具体取决于特定金属以及可能的火前泥炭金属浓度。泥炭火灾后，地球化学和水文变化变得越来越重要。 例如，火灾后 pH 值的增加在限制 TMM 动员方面发挥了最强的化学作用，但溶解有机物芳香性的同时增加使我们对这些过程的理解变得复杂，导致了关键的知识差距。在更大的空间尺度上，泥炭地和流域的生态水文连通性和泥炭侵蚀调节TMMs向水生系统的释放。然而，随着泥炭地植被和水文在几年到数十年的时间内恢复到火灾前的条件，生态水文连通性和泥炭侵蚀潜力的演变受到影响火灾前TMM流动性的相同控制的控制。至关重要的是，进化轨迹的不确定性取决于生物、水文、气候和化学条件的变化，限制了我们在快速变化的气候下准确预测这些变化的能力。这项广泛的跨学科审查指导了概念框架的制定，并强调了未来的研究需要，以更好地应对泥炭地野火遗留 TMM 释放所带来的新威胁。