Abstract The chemical composition of coal ash is highly heterogeneous and dependent on the origin of the source coal, combustion parameters, and type and configuration of air pollution control devices. This heterogeneity results in uncertainty in the evaluation of leaching potential of contaminants from coal ash. The goal of this work was to identify whether a single leaching protocol could roughly group high-leaching potential coal ash from low-leaching potential coal ash, with respect to arsenic (As) and selenium (Se). We used four different leaching tests, including the Toxicity Characteristic Leaching Protocol (TCLP), natural pH, aerobic sediment microcosms, and anaerobic sediment microcosms on 10 different coal ash materials, including fly ash, lime-treated ash, and flue gas desulfurization materials. Leaching tests showed promise in categorizing high and low-leaching potential ash materials, indicating that a single point test could act as a first screening measure to identify high-risk ash materials. However, the amount of contaminant leached varied widely across tests, reflecting the importance of ambient conditions (pH, redox state) on leaching. These results demonstrate that on-site geochemical conditions play a critical role in As and Se mobilization from coal ash, underscoring the need to develop a situation-based risk assessment framework for contamination by coal ash pollutants.

中文翻译：

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煤灰材料浸出砷和硒的潜力排名：灰分化学和场地生物地球化学的相对重要性

摘要 煤灰的化学成分高度不均匀，取决于源煤的来源、燃烧参数以及空气污染控制装置的类型和配置。这种异质性导致评估煤灰污染物浸出潜力的不确定性。这项工作的目标是确定单一浸出方案是否可以将高浸出率煤灰与低浸出率煤灰大致分为砷 (As) 和硒 (Se)。我们对 10 种不同的煤灰材料（包括飞灰、石灰处理灰和烟气脱硫材料）使用了四种不同的浸出试验，包括毒性特征浸出方案 (TCLP)、自然 pH、好氧沉积物微观世界和厌氧沉积物微观世界。浸出测试显示出对高浸出和低浸出潜力灰分材料进行分类的前景，表明单点测试可以作为识别高风险灰分材料的第一筛选措施。然而，浸出的污染物量在测试中差异很大，反映了环境条件（pH 值、氧化还原状态）对浸出的重要性。这些结果表明，现场地球化学条件在煤灰中 As 和 Se 的动员中起着关键作用，强调需要制定基于情况的煤灰污染物污染风险评估框架。反映了环境条件（pH、氧化还原状态）对浸出的重要性。这些结果表明，现场地球化学条件在煤灰中 As 和 Se 的动员中起着关键作用，强调需要制定基于情况的煤灰污染物污染风险评估框架。反映了环境条件（pH、氧化还原状态）对浸出的重要性。这些结果表明，现场地球化学条件在煤灰中 As 和 Se 的动员中起着关键作用，强调需要制定基于情况的煤灰污染物污染风险评估框架。