College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Aug;25(24):23780-23790. doi: 10.1007/s11356-018-2456-6. Epub 2018 Jun 6.
In order to investigate level and potential sources of polycyclic aromatic hydrocarbons (PAHs) in wheat fields affected by coal combustion in Henan and Shaanxi Provinces and to investigate distribution and transfer of PAHs in winter wheat grown in the areas, various tissues of the crop and the corresponding rhizosphere soils were collected during the harvest season of winter wheat. The mean concentrations of USEPA 15 priority PAHs (sum of the three- to six-ring PAHs) ranged from 486 to 1117 μg kg in the rhizosphere soils, indicating serious PAH contamination. Based on both the isomeric ratios of PAHs and a principal component analysis (PCA), the main sources of PAHs in the agricultural soils were from combustion of biomass, coal and petroleum, and petroleum. ∑PAHs were significantly (p < 0.001) higher in the roots (287-432 μg kg) than those in aerial tissues (221-310 μg kg). There were two decreasing gradients of PAH concentrations, one from roots, stems to leaves, and the other from glumes to grains. Regardless of sampling sites, most PAHs detected in the roots and in the aerial tissues were three-ring PAHs (acenaphthene, acenaphthylene, fluorene, phenanthrene, and anthracene) and the percentages of three-ring PAHs were much higher in the aerial tissues (72.5-82.7%) than in the roots (49.5-74.0%) and in the rhizosphere soils (36.3-65.7%). The distribution of PAHs with different ring numbers in the stems, leaves, and glumes was quite similar to each other but was significantly different from that of the roots and rhizosphere soils. Combined with significant results from partial correlation and linear regression models, the present study suggested that partial three- to four-ring PAHs in the aerial tissues are derived from root-soil uptake and that six-ring PAHs may come from the air-to-leaf pathway, although the quantity contribution of foliar uptake and root uptake was yet to be further studied.
为了调查河南和陕西省受燃煤影响的麦田中多环芳烃（PAHs）的水平和潜在来源，并研究这些地区冬小麦中 PAHs 的分布和迁移，在冬小麦收获季节采集了作物的各种组织和相应的根际土壤。根际土壤中 USEPA 15 种优先 PAHs（三环至六环 PAHs 的总和）的平均浓度范围为 486 至 1117μg/kg，表明存在严重的 PAH 污染。基于 PAHs 的同系物比值和主成分分析（PCA），农业土壤中 PAHs 的主要来源是生物质、煤和石油燃烧以及石油。∑PAHs 在根部（287-432μg/kg）明显高于地上组织（221-310μg/kg）（p<0.001）。PAH 浓度存在两个递减梯度，一个从根部到茎，另一个从颖片到谷物。无论采样地点如何，根部和地上组织中检测到的大多数 PAHs 都是三环 PAHs（苊、苊烯、芴、菲和蒽），而且三环 PAHs 在地上组织中的比例（72.5-82.7%）明显高于根部（49.5-74.0%）和根际土壤（36.3-65.7%）。不同环数 PAHs 在茎、叶和颖片中的分布彼此非常相似，但与根部和根际土壤有显著差异。结合偏相关和线性回归模型的显著结果，本研究表明，地上组织中部分三至四环 PAHs 来源于根-土吸收，六环 PAHs 可能来自空气-叶途径，尽管叶吸收和根吸收的数量贡献还需要进一步研究。
