Wildfires in radiologically contaminated areas raise significant concerns due to potential radionuclides redistribution and increased public radiation exposure. This study examined the impact of the 2020 Chornobyl wildfire on the redistribution of radionuclides, specifically ¹³⁷Cs and ⁹⁰Sr, in the Chornobyl River system. We determined the quantities and speciation of ¹³⁷Cs and ⁹⁰Sr in charred residues and soil after wildfires and analyzed the riverine concentrations of these radionuclides based on long-term monitoring data. Our findings indicate that the inventories of ¹³⁷Cs and ⁹⁰Sr in the charred residues and soil decreased with increasing distance from the nuclear power plant, which is consistent with the initial deposition patterns. However, the transfer of ¹³⁷Cs and ⁹⁰Sr from soil to charred residues did not correspond to the distance, type of contamination source, or fire type. Speciation analysis revealed that the water-soluble fractions of ¹³⁷Cs and ⁹⁰Sr in the charred residues were significantly higher than those in the soil, implying increased mobility. Following the wildfires, no significant increase in ¹³⁷Cs concentration was observed in a river catchment in Chornobyl. However, ⁹⁰Sr concentrations showed a significant increase, exceeding the permissible levels in drinking water (2 Bq/L) in Ukraine. This increase is attributed to hydrologically driven mobilization processes: (1) during snowmelt in spring and (2) the transport of soluble ⁹⁰Sr from charred residues and surface soil into the river during high suspended solid concentration events. Collectively, our findings highlight the importance of continuous monitoring of radionuclide dynamics in postwildfire environments to better assess potential radionuclide redistribution and radiation exposure risks. These results provide valuable insights into the behavior of ¹³⁷Cs and ⁹⁰Sr in river systems affected by wildfires, contributing to a more accurate understanding of their environmental impacts and potential countermeasures.

中文翻译：

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大规模野火对切尔诺贝利河系统中放射性核素再分布的影响


由于放射性核素的潜在重新分布和公共辐射暴露的增加，放射性污染地区的野火引起了人们的严重关注。本研究考察了 2020 年切尔诺贝利野火对切尔诺贝利河系统中放射性核素重新分布的影响，特别是 ¹³⁷Cs 和 ⁹⁰Sr。我们确定了野火后烧焦残留物和土壤中 ¹³⁷Cs 和 ⁹⁰Sr 的数量和形态，并根据长期监测数据分析了这些放射性核素的河流浓度。我们的研究结果表明，随着与核电站距离的增加，烧焦残渣和土壤中 ¹³⁷Cs 和 ⁹⁰Sr 的存量减少，这与初始沉积模式一致。然而，¹³⁷Cs 和 ⁹⁰Sr 从土壤转移到烧焦的残留物与距离、污染源类型或火灾类型不符。形态分析显示，烧焦残留物中 ¹³⁷Cs 和 ⁹⁰Sr 的水溶性组分明显高于土壤中的水溶性组分，这意味着流动性增加。野火过后，在切尔诺贝利的一个河流集水区没有观察到 ¹³⁷Cs 浓度的显着增加。然而，⁹⁰Sr 浓度显示显着增加，超过了乌克兰饮用水中的允许水平 （2 Bq/L）。这种增加归因于水文驱动的动员过程：（1） 春季融雪期间和 （2） 在高悬浮固体浓度事件期间，可溶性 ⁹⁰Sr 从烧焦的残留物和表层土壤中输送到河流中。 总的来说，我们的研究结果强调了在野火后环境中持续监测放射性核素动态的重要性，以更好地评估潜在的放射性核素再分布和辐射暴露风险。这些结果为受野火影响的河流系统中 ¹³⁷Cs 和 ⁹⁰Sr 的行为提供了有价值的见解，有助于更准确地了解其环境影响和潜在的对策。