Chemical characteristics of wildfire ash across the globe and their environmental and socio-economic implications
Chemical characteristics of wildfire ash across the globe and their environmental and socio-economic implications
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全球野火灰的化学特征及其环境和社会经济影响
DOI：
10.1016/j.envint.2023.108065
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发表时间：
2023
影响因子：
11.8
通讯作者：
Sánchez-García C
中科院分区：
文献类型：
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作者：
Sánchez-García C
野火灰烬中潜在有害化学成分的动员可能是野火的一个主要后果，构成广泛的社会风险。对野火灰烬化学成分的了解对于预测和缓解这些风险至关重要。在这里，我们提供了一个关于全球范围内野火灰烬(42种类型，总共148个样本)的化学特征的综合数据集，并研究了它们潜在的社会和环境影响。为了补充和比较我们的火山灰数据，我们还广泛地回顾了分析火山灰化学成分的研究。我们数据集中的大多数火山灰都发生了碱性反应(平均PH值8.8，范围在6到11.2之间)。野火灰的重要成分是有机碳(平均：204g/kg−1)、钙、铝和铁(平均：47.9g/kg−1、17.9%和17.1%)。平均氮和磷的平均值分别为1至25微克/公斤−1和0.2至9.9微克/公斤−1。与人类和生态系统健康有关的金属浓度最大的是锰(平均：1488万毫克/公斤−1；三个生态系统)和锌(平均：18110万毫克/公斤−1；两个生态系统：500亿毫克/公斤−1)和铅(平均：66.9亿毫克/公斤−1；两个生态系统)和200亿毫克/公斤−1)。燃烧严重程度和采样时间是影响灰分化学特性(如pH、碳和氮浓度)的关键因素。水中最易溶解的部分(占灰分干重的百分比)是钠(18%)和镁(11.4%)。尽管一些火山灰中令人担忧的元素浓度非常接近或超过国际污染标准，但火山灰的实际影响将取决于火山灰负荷以及对水、土壤和沉积物等环境基质的稀释等因素。我们的方法可以作为野火灰样和化学分析协议的初步方法学标准化。
The mobilisation of potentially harmful chemical constituents in wildfire ash can be a major consequence of wildfires, posing widespread societal risks. Knowledge of wildfire ash chemical composition is crucial to anticipate and mitigate these risks.Here we present a comprehensive dataset on the chemical characteristics of a wide range of wildfire ashes (42 types and a total of 148 samples) from wildfires across the globe and examine their potential societal and environmental implications. An extensive review of studies analysing chemical composition in ash was also performed to complement and compare our ash dataset.Most ashes in our dataset had an alkaline reaction (mean pH 8.8, ranging between 6 and 11.2). Important constituents of wildfire ash were organic carbon (mean: 204 g kg−1), calcium, aluminium, and iron (mean: 47.9, 17.9 and 17.1 g kg−1). Mean nitrogen and phosphorus ranged between 1 and 25 g kg−1, and between 0.2 and 9.9 g kg−1, respectively. The largest concentrations of metals of concern for human and ecosystem health were observed for manganese (mean: 1488 mg kg−1; three ecosystems > 1000 mg kg−1), zinc (mean: 181 mg kg−1; two ecosystems > 500 mg kg−1) and lead (mean: 66.9 mg kg−1; two ecosystems > 200 mg kg−1). Burn severity and sampling timing were key factors influencing ash chemical characteristics like pH, carbon and nitrogen concentrations. The highest readily dissolvable fractions (as a % of ash dry weight) in water were observed for sodium (18 %) and magnesium (11.4 %). Although concentrations of elements of concern were very close to, or exceeded international contamination standards in some ashes, the actual effect of ash will depend on factors like ash loads and the dilution into environmental matrices such as water, soil and sediment. Our approach can serve as an initial methodological standardisation of wildfire ash sampling and chemical analysis protocols.