The distribution of the sixteen priority polycyclic aromatic hydrocarbons (PAHs) in different components of field aged soil was investigated. Furthermore, the desorption and bioaccessibility of high molecular weight (HMW) PAHs with five and six aromatic rings were explored using XAD-2 resin-assisted desorption assay due to their high carcinogenicity, and Fourier Transform Infrared Spectroscopy (FTIR) was used to uncover the functional groups controlling PAHs bioaccessibility. It was revealed that nearly 99% PAHs were retained in mineral and humin-like fractions (HU), and the percentages reserved by HU fraction increase as aromatic ring increase. The accumulated HMW PAHs desorbed during the 120 d desorption experiment were 34 ~ 44% in soil with particle diameter less than 0.2 mm (referred as bulk soil hereafter) while 32 ~ 46% in HU. The desorption kinetics can be regressed well using the two-compartment model, and the fast desorption rates for bulk soil and HU were on the order of 10^–2 d⁻¹, an order of magnitude higher than the corresponding slow desorption rates. The FTIR spectra revealed that de-ashing the raw HU may expose PAHs combined with hydrophobic groups inside the mineral-organic complex to the desorption system, resulting in an overestimation of the bioaccessibility.

中文翻译：

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高分子量多环芳烃在老田土壤和焦炭厂类腐殖质中的解吸和生物利用度

研究了十六种优先多环芳烃在田间老化土壤不同组分中的分布。此外，由于具有高致癌性，使用XAD-2树脂辅助解吸试验探索了具有五个和六个芳香环的高分子量（HMW）PAH的解吸性和生物可及性，并使用傅里叶变换红外光谱（FTIR）来发现控制PAHs生物可及性的官能团。结果表明，将近99％的PAHs保留在矿物质和类腐殖质组分（HU）中，并且随着芳香环的增加，HU组分保留的百分数也随之增加。在120 d解吸实验中，解吸的HMW PAHs在粒径小于0.2 mm的土壤（以下称为散装土壤）中为34％〜44％，而在HU中为32％〜46％。^–2 d ^-1，比相应的缓慢解吸速率高一个数量级。FTIR光谱显示，对原始HU进行除灰可将PAHs与矿物-有机复合物中的疏水基团结合到解吸系统中，从而导致对生物可及性的高估。