Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, SE-750 07, Uppsala, Sweden.
Geological Survey of Sweden, Box 670, SE-751 28, Uppsala, Sweden.
Environ Pollut. 2023 Sep 15;333:121992. doi: 10.1016/j.envpol.2023.121992. Epub 2023 Jun 20.
Atmospheric deposition is the most dominant source of polycyclic aromatic hydrocarbons (PAHs) in remote and pristine areas. Despite low bioaccumulation potential, PAHs and their persistent transformation products (PAH-derivatives) are chemicals of concern as they can harm human and animal health through chronic low dose exposure. In this study, atmospheric deposition fluxes of polycyclic aromatic compounds (PACs) were measured on a seasonal basis (3-month periods) from 2012 to 2016 in a remote subarctic forest catchment in northern Europe. The target PACs included 19 PAHs and 15 PAH-derivatives (oxygenated, nitrogenated, and methylated PAHs). The deposition fluxes of ƩPAHs and ƩPAH-derivatives were in the same range and averaged 530 and 500 ng m day, respectively. The fluxes were found to be higher with a factor of 2.5 for ƩPAHs and a factor of 3 for ƩPAH-derivatives during cold (<0 °C) in comparison to warm (>10 °C) periods. PAHs and PAH-derivatives showed similar seasonal patterns, which suggests that these two compound classes have similar sources and deposition mechanisms, and that the source strength of the PAH-derivatives in air follows that of the PAHs. The terrestrial export of PACs via the outlet of the catchment stream was estimated to be 1.1% for ƩPAHs and 1.7% for ƩPAH-derivatives in relation to the annual amounts deposited to the catchment, which suggests that boreal forests are sinks for PACs derived from the atmosphere. Some individual PACs showed higher export than others (i.e. chrysene, cyclopenta(c,d)pyrene, carbazole, quinoline, and benzo(f)quinoline), with high export PACs mostly characterized by low molecular weight and low hydrophobicity (2-3 benzene rings; log K<6.0).
大气沉降是偏远和原始地区多环芳烃（PAHs）的最主要来源。尽管生物累积潜力较低，但 PAHs 及其持久性转化产物（PAH 衍生物）是令人关注的化学物质，因为它们通过慢性低剂量暴露会对人类和动物健康造成危害。在这项研究中，从 2012 年到 2016 年，在北欧一个偏远的亚北极森林流域，按季节（3 个月为一个周期）测量了多环芳烃化合物（PACs）的大气沉降通量。目标 PACs 包括 19 种 PAHs 和 15 种 PAH 衍生物（含氧、含氮和含甲基的 PAHs）。ΣPAHs 和 ΣPAH 衍生物的沉积通量处于同一范围内，分别平均为 530 和 500 ng m-2 d-1。与温暖期（>10°C）相比，寒冷期（<0°C）时 ΣPAHs 的通量高 2.5 倍，ΣPAH 衍生物的通量高 3 倍。PAHs 和 PAH 衍生物表现出相似的季节性模式，这表明这两类化合物具有相似的来源和沉积机制，并且空气中 PAH 衍生物的源强与 PAHs 相同。通过流域出口估算了 PACs 通过流域出口的陆地输出量，与沉积到流域的年总量相比，ΣPAHs 为 1.1%，ΣPAH 衍生物为 1.7%，这表明北方森林是大气来源 PACs 的汇。一些个别 PACs 的输出量高于其他 PACs（即䓛、苊烯、咔唑、喹啉和苯并（f）喹啉），高输出 PACs 的特征主要是分子量低、疏水性低（2-3 个苯环；log K<6.0）。
