Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.
Environ Toxicol Chem. 2011 Dec;30(12):2674-81. doi: 10.1002/etc.682. Epub 2011 Oct 19.
The distribution and potential bioavailability of polycyclic aromatic hydrocarbons (PAHs) in soil from a former manufactured-gas plant (MGP) site were examined before and after long-term biostimulation under simulated in situ conditions. Treated soil was collected from the oxygenated zones of two continuous-flow columns, one subjected to biostimulation and the other serving as a control, and separated into low- and high-density fractions. In the original soil, over 50% of the total PAH mass was associated with lower density particles, which made up <2% of the total soil mass. However, desorbable fractions of PAHs were much lower in the low-density material than in the high-density material. After more than 500 d of biostimulation, significant removal of total PAHs occurred in both the high- and low-density materials (77 and 53%, respectively), with three- and four-ring PAHs accounting for the majority of the observed mass loss. Total PAHs that desorbed over a 28-d period were substantially lower in treated soil from the biostimulated column than in the original soil for both the high-density material (23 vs. 63%) and the low-density material (5 vs. 20%). The fast-desorbing fractions quantified by a two-site desorption model ranged from 0.1 to 0.5 for most PAHs in the original soil but were essentially zero in the biostimulated soil. The fast-desorbing fractions in the original soil underestimated the extent of PAH biodegradation observed in the biostimulated column and thus was not a good predictor of PAH bioavailability after long-term, simulated in situ biostimulation.
在模拟原位条件下进行长期生物刺激之前和之后，研究了来自前煤气厂（MGP）厂址的土壤中多环芳烃（PAHs）的分布和潜在生物可利用性。从两个连续流动柱的充氧区采集处理过的土壤，一个进行生物刺激，另一个作为对照，并将其分离成低密度和高密度部分。在原始土壤中，超过 50%的总 PAH 质量与较低密度的颗粒有关，这些颗粒仅占土壤总质量的<2%。然而，在低密度物质中，可解吸的 PAH 分数远低于高密度物质。经过超过 500 天的生物刺激，高密度和低密度材料中的总 PAHs 都有显著去除（分别为 77%和 53%），三环和四环 PAHs 占观察到的质量损失的大部分。在生物刺激柱的处理土壤中，经过 28 天解吸的总 PAHs 远低于原始土壤中的高、低密度材料（分别为 23%对 63%和 5%对 20%）。通过双位点解吸模型量化的快速解吸分数对于原始土壤中的大多数 PAHs 在 0.1 到 0.5 之间，但在生物刺激土壤中基本为零。原始土壤中的快速解吸分数低估了生物刺激柱中观察到的 PAH 生物降解程度，因此不是长期模拟原位生物刺激后 PAH 生物可利用性的良好预测指标。
