Pollution due to polycyclic aromatic hydrocarbons (PAHs) is a serious environmental issue. The aim of this study was to determine the effect of stand species composition on PAH content. The research covered the stand soils of the Rybnik Forest District, which experiences some of the highest deposition of industrial emissions in Europe. Pine, pine–oak and oak stands growing in the same soil conditions were selected for the study. Samples for further analyses were collected from the organic, humus mineral and mineral soil horizons. The organic C and N concentrations, pH, alkaline cation content, microbiological biomass of C and N, soil enzyme activity, soil organic matter (SOM) fractions and PAH content were determined. The oak stand soils were characterised by the lowest accumulation of PAHs (2936.0 μg kg⁻¹) with high biochemical activity expressed by enzyme activity (dehydrogenases, N-acetyl-β-d-glucosaminidase, phosphatase) and high microbiological biomass. In contrast, pine stand soils are acidified; hence, SOM decomposition is slowed, resulting in a high accumulation of PAHs (3805.0 μg kg⁻¹). A strong correlation (r = 0.825) between PAH accumulation and SOM free light fraction (fLF) C concentration was noted. The stand species composition plays an important role in shaping the quality and quantity of SOM and soil acidification, which is reflected in the microbial activity and PAH accumulation in forest soils. Such accumulation in forest soils is related to the fractional composition of SOM, which is due to the influence of species composition through the supplied biomass.

中文翻译：

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不同温带林分土壤层位多环芳烃积累

多环芳烃 (PAHs) 造成的污染是一个严重的环境问题。本研究的目的是确定林分物种组成对 PAH 含量的影响。该研究涵盖了雷布尼克森林区的林区土壤，该区经历了欧洲工业排放量最高的一些地区。选择在相同土壤条件下生长的松树、松橡树和橡树林进行研究。从有机、腐殖质矿物和矿物土壤层中收集用于进一步分析的样品。测定了有机碳和氮的浓度、pH、碱性阳离子含量、碳和氮的微生物量、土壤酶活性、土壤有机质（SOM）组分和多环芳烃含量。橡树林土壤的特点是多环芳烃的最低积累（2936.0 μg kg ^-1) 具有以酶活性（脱氢酶、N-乙酰-β - d-氨基葡萄糖苷酶、磷酸酶）和高微生物量表示的高生化活性。相反，松林土壤被酸化；因此，SOM 分解减慢，导致 PAHs 大量积累（3805.0 μg kg ^-1）。强相关性（r = 0.825) 在 PAH 积累和 SOM 游离轻馏分 (fLF) C 浓度之间进行了记录。林分物种组成在塑造 SOM 的质量和数量以及土壤酸化方面起着重要作用，这反映在森林土壤中的微生物活性和 PAH 积累上。森林土壤中的这种积累与 SOM 的部分组成有关，这是由于物种组成通过供应的生物量的影响。