Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan; Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
Chemosphere. 2021 May;271:129824. doi: 10.1016/j.chemosphere.2021.129824. Epub 2021 Feb 2.
Black carbon (BC) is a pyrolyzed product derived from incomplete combustion. A major fraction of BC produced by landscape fires is initially deposited onto onsite soils. Atmospheric deposition of soot is known to be an important source of soil BC, especially in watersheds that are not affected by landscape fires. The transport of the dissolved fraction of oxidized BC in soil, defined as dissolved black carbon (DBC), to streams is considered one of the important loss pathways of BC in soil, but the mechanism is not well documented. We measured the quantity and quality of DBC, determined by a benzenepolycarboxylic acid method, and the quantitative and qualitative parameters of bulk dissolved organic matter (DOM) in streams in Hokkaido, northern Japan, whose catchments were not affected by landscape fire for at least 110 years. DBC with relatively low polycondensed signatures occurred in the streams, irrespective of differences in watershed characteristics and seasons, suggesting that atmospheric deposition of soot into the catchment is probably a major source of stream DBC. The DBC concentration was linearly related to the dissolved organic carbon (DOC) concentration, irrespective of the differences in watershed characteristics and seasons. Furthermore, the polycondensation degree of DBC was observed to correlate with the qualitative parameters of bulk DOM. Such quantitative and qualitative relationships between DBC and bulk DOM imply that the transfer mechanism from soils to streams of soot-derived polycondensed DBC is linked with that of higher plant-derived, high-molecular-weight aromatic DOM.
黑碳（BC）是一种由不完全燃烧产生的热解产物。景观火灾产生的 BC 主要部分最初沉积在现场土壤上。已知烟尘的大气沉积是土壤 BC 的一个重要来源，特别是在不受景观火灾影响的流域。土壤中氧化 BC 的溶解部分（定义为溶解黑碳（DBC））向溪流的迁移被认为是土壤中 BC 的重要损失途径之一，但该机制尚未得到很好的记录。我们测量了日本北海道溪流中 DBC 的数量和质量，采用苯多羧酸法测定，以及溪流中总溶解有机物质（DOM）的定量和定性参数，这些溪流的流域至少 110 年没有受到景观火灾的影响。无论流域特征和季节的差异如何，溪流中都存在相对低缩合特征的 DBC，这表明烟尘向流域的大气沉积可能是溪流 DBC 的主要来源。DBC 浓度与溶解有机碳（DOC）浓度呈线性关系，而与流域特征和季节无关。此外，DBC 的缩合程度与总 DOM 的定性参数有关。DBC 和总 DOM 之间的这种定量和定性关系表明，源于烟尘的缩合 DBC 从土壤向溪流的迁移机制与源自高等植物的高分子量芳香族 DOM 的迁移机制有关。
