Soil Science Group, Geographic Institute, University of Bern, 3012 Bern, Switzerland.
Soil Science Group, Geographic Institute, University of Bern, 3012 Bern, Switzerland.
Chemosphere. 2014 Jul;107:407-414. doi: 10.1016/j.chemosphere.2014.01.017. Epub 2014 Feb 11.
Environmental conditions in the tropics favor the formation of polar polycyclic aromatic compound (polar PACs, such as oxygenated PAHs [OPAHs] and azaarenes [AZAs]), but little is known about these hazardous compounds in tropical soils. The objectives of this work were to determine (i) the level of contamination of soils (0-5 and 5-10 cm layers) from the tropical metropolis of Bangkok (Thailand) with OPAHs and AZAs and (ii) the influence of urban emission sources and soil properties on the distribution of PACs. We hypothesized that the higher solar insolation and microbial activity in the tropics than in the temperate zone will lead to enhanced secondary formation of OPAHs. Hence, OPAH to related parent-PAH ratios will be higher in the tropical soils of Bangkok than in temperate soils of Bratislava and Gothenburg. The concentrations of ∑15OPAHs (range: 12-269 ng g(-1)) and ∑4AZAs (0.1-31 ng g(-1)) measured in soils of Bangkok were lower than those in several cities of the industrialized temperate zone. The ∑15OPAHs (r=0.86, p<0.01) and ∑4AZAs (r=0.67, p<0.01) correlated significantly with those of ∑20PAHs highlighting similar sources and related fate. The octanol-water partition coefficient did not explain the transport to the subsoil, indicating soil mixing as the reason for the polar PAC load of the lower soil layer. Data on PAC concentrations in soils of Bratislava and Gothenburg were taken from published literature. The individual OPAH to parent-PAH ratios in soils of Bangkok were mostly higher than those of Bratislava and Gothenburg (e.g. 9-fluorenone/fluorene concentration ratio was 12.2 ± 6.7, 5.6 ± 2.4, and 0.7 ± 02 in Bangkok, Bratislava and Gothenburg soils, respectively) supporting the view that tropical environmental conditions and higher microbial activity likely lead to higher OPAH to parent-PAH ratios in tropical than in temperate soils.
在热带地区，环境条件有利于形成极性多环芳烃化合物（极性 PACs，如含氧多环芳烃 [OPAHs] 和氮杂芳烃 [AZAs]），但关于热带土壤中这些有害化合物的信息却很少。本研究的目的是确定（i）泰国曼谷热带大都市的土壤（0-5 和 5-10 cm 层）中 OPAHs 和 AZAs 的污染程度，以及（ii）城市排放源和土壤特性对 PAC 分布的影响。我们假设，与温带地区相比，热带地区更高的太阳辐射和微生物活性将导致 OPAHs 的次生形成增强。因此，曼谷热带土壤中的 OPAH 与相关母体多环芳烃的比值将高于布拉迪斯拉发和哥德堡的温带土壤。在所研究的曼谷土壤中，∑15OPAHs（范围：12-269 ng g(-1)) 和∑4AZAs（0.1-31 ng g(-1)) 的浓度低于工业化温带城市的几个城市。∑15OPAHs（r=0.86，p<0.01）和∑4AZAs（r=0.67，p<0.01）与∑20PAHs 显著相关，突出了相似的来源和相关的命运。辛醇-水分配系数不能解释其向底土的迁移，这表明土壤混合是造成下层土壤极性 PAC 负荷的原因。布拉迪斯拉发和哥德堡土壤中 PAC 浓度的数据取自已发表的文献。曼谷土壤中个别 OPAH 与母体-PAH 的比值大多高于布拉迪斯拉发和哥德堡（例如，9-氟酮/芴的浓度比分别为 12.2±6.7、5.6±2.4 和 0.7±02），这支持了这样一种观点，即热带环境条件和更高的微生物活性可能导致热带土壤中 OPAH 与母体-PAH 的比值高于温带土壤。
