Polycyclic aromatic hydrocarbons (PAHs) are a class of contaminants characterized by their persistent and toxic nature. This study examines the variability in PAH distribution patterns in the upper layers of forest soils, focusing on the influence of different characteristics of individual soil (sub)horizons. A total of 130 samples were collected from five forest areas in south‐central Poland and analyzed for the 16 priority PAHs. Samples were taken from the organic fermentative‐humic (Ofh), humic (A), and humic‐eluvial (AE) (sub)horizons. The highest mean concentrations of total PAHs were found in the subhorizon‐Ofh (Ofh—1547 μg kg−1, A—1103 μg kg−1, AE—109 μg kg−1). The PAH content was significantly correlated with SOM content and pH, but this correlation was only significant in the horizon‐A. The percentage contributions of 3‐, 4‐, 5‐, and 6‐ring compounds to the total PAHs varied among the investigated soil (sub)horizons. The subhorizon‐Ofh had the highest percentage contribution of 6‐ring PAHs, 4‐ and 5‐ring PAHs were most prevalent in the horizon‐A, while 3‐ring compounds in the horizon‐AE. The variability in PAH patterns was also reflected in individual PAH ratios (BaA/BaA+Chr, IcdP/IcdP+BghiP), confirming the different behavior of 4‐, 5‐, and 6‐ring compounds in these (sub)horizons. This suggests that the retention of PAHs in the investigated (sub)horizons is influenced by several factors, including pH, degree of SOM decomposition, and mineral fraction, each to a different extent. Our findings reveal significant knowledge gaps regarding the behavior and accumulation of PAHs in soil (sub)horizons, underscoring the need for further research.

中文翻译：

---

上层森林土壤（亚）层中 PAH 模式的变化——来自波兰中南部的案例研究


多环芳烃 （PAH） 是一类污染物，其特征是其持久性和毒性。本研究考察了森林土壤上层 PAH 分布模式的变化，重点关注单个土壤（亚）层不同特征的影响。从波兰中南部的 5 个森林地区共收集了 130 个样本，并分析了 16 种优先 PAH。样品取自有机发酵腐殖质 （Ofh）、腐殖质 （A） 和腐殖质 （AE） （亚）层。总多环芳烃的平均浓度最高出现在亚水平 Ofh 中 （Ofh—1547 μg kg-1， A—1103 μg kg-1， AE—109 μg kg-1）。PAH 含量与 SOM 含量和 pH 值显著相关，但这种相关性仅在水平 A 中显著。3 环、4 环、5 环和 6 环化合物对总多环芳烃的贡献在所研究的土壤（亚）层中有所不同。亚水平 Ofh 对 6 环 PAH 的贡献百分比最高，4 环和 5 环 PAH 在水平 A 中最为普遍，而 3 环化合物在水平 AE 中最普遍。PAH 模式的可变性也反映在单个 PAH 比率 （BaA/BaA+Chr、IcdP/IcdP+BghiP） 中，证实了 4 环、5 环和 6 环化合物在这些（亚）水平中的不同行为。这表明 PAH 在所研究的（亚）层位中的保留受多种因素的影响，包括 pH 值、SOM 分解程度和矿物馏分，每个因素的程度都不同。我们的研究结果揭示了关于土壤（亚）层中 PAH 的行为和积累的巨大知识差距，强调了进一步研究的必要性。