Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
Environ Pollut. 2017 Nov;230:882-890. doi: 10.1016/j.envpol.2017.07.038. Epub 2017 Jul 20.
To elucidate the environmental fate of polycyclic aromatic hydrocarbons (PAHs) once released into soil, sixteen humic acids (HAs) and one humin (HM) fractions were sequentially extracted from a peat soil, and sixteen priority PAHs in these humic substances (HSs) were analyzed. It was found that the total concentration of 16 PAHs (∑16PAHs) increased evidently from HA1 to HA16, and then dramatically reached the highest value in HM. The trend of ∑16PAHs in HAs relates to surface carbon and C-H/C-C contents, the bulk aliphatic carbon content and aliphaticity, as well as the condensation enhancement of carbon domains, which were derived from elemental composition, XPS, C NMR, as well as thermal analyses. HM was identified to be the dominant sink of 16 PAHs retention in soil, due to its aliphatic carbon-rich chemical composition and the highly condensed physical makeup of its carbon domains. This study highlights the joint roles of the physical and chemical properties of HSs in retention of PAHs in soil and the associated mechanisms; the results are of significance for PAH-polluted soil risk assessment and remediation.
为了阐明多环芳烃（PAHs）一旦释放到土壤中后的环境归宿，本研究从泥炭土中依次提取了 16 种腐殖酸（HA）和 1 种腐殖质（HM）级分，并对这些腐殖物质中的 16 种优先 PAHs 进行了分析。结果发现，16 种 PAHs 的总浓度（∑16PAHs）从 HA1 到 HA16 明显增加，然后在 HM 中急剧达到最高值。HA 中∑16PAHs 的趋势与表面碳和 C-H/C-C 含量、整体脂肪碳含量和脂肪化程度以及碳域的凝聚增强有关，这些特征源于元素组成、XPS、C NMR 以及热分析。由于 HM 具有富含脂肪碳的化学组成和高度凝聚的碳域物理结构，因此被确定为土壤中 16 种 PAHs 保留的主要汇。本研究强调了 HSs 的物理和化学性质在土壤中 PAHs 保留中的共同作用及其相关机制；这些结果对于 PAH 污染土壤风险评估和修复具有重要意义。
