Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, Barcelona, Catalonia, 08034, Spain.
Environ Sci Technol. 2011 Jun 1;45(11):4740-7. doi: 10.1021/es104131f. Epub 2011 May 2.
Soils are a major reservoir of organic pollutants, and soil-air partitioning and exchange are key processes controlling the regional fate of pollutants. Here, we report and discuss the soil concentrations of polycyclic aromatic hydrocarbons (PAHs), their soil fugacities, the soil-air partition coefficients (K(SA)) and soil-air gradients for rural and semirural soils, in background areas of N-NE Spain and N-NW England. Different sampling campaigns were carried out to assess seasonal variability and differences between sampling sites. K(SA) values were dependent on soil temperature and soil organic quantity and type. Soil fugacities of phenanthrene and its alkyl homologues were 1-2 orders of magnitude higher than their ambient air fugacities for all sampling sites and periods. The soil to air fugacity ratio was correlated with soil temperature and soil redox potential. Similar trends for other PAHs were found but with lower fugacity ratios. The ubiquitous source of PAHs from background soils to the atmosphere found in all temperate regions in different seasons provides an indirect evidence of potential in situ generation of two to four ring PAHs and their alkyl homologues in the surface soil. We discuss this hypothetical biogenic source and other potential processes that could drive the high soil to air fugacity ratios of some PAHs.
土壤是有机污染物的主要储存库，土壤-空气分配和交换是控制污染物区域归宿的关键过程。在这里，我们报告并讨论了西班牙东北部和英格兰西北部背景地区农村和半农村土壤中多环芳烃 (PAHs) 的浓度、它们的土壤逸度、土壤-空气分配系数 (K(SA)) 和土壤-空气梯度。进行了不同的采样活动来评估季节性变化和采样点之间的差异。K(SA) 值取决于土壤温度和土壤有机质量和类型。对于所有采样点和时间段，菲和其烷基同系物的土壤逸度比其环境空气逸度高 1-2 个数量级。土壤到空气逸度比与土壤温度和土壤氧化还原电位相关。发现其他 PAHs 也有类似的趋势，但逸度比较低。在不同季节的所有温带地区，从背景土壤到大气的 PAHs 普遍来源为多环芳烃在地表土壤中就地生成二到四环 PAHs 及其烷基同系物提供了间接证据。我们讨论了这种假设的生物源以及可能导致某些 PAHs 的高土壤-空气逸度比的其他潜在过程。
