title: Oxygenated polycyclic aromatic hydrocarbons and azaarenes in urban soils: a comparison of a tropical city (Bangkok) with two temperate cities (Bratislava and Gothenburg).
abstract: 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.
authors: Soil Science Group, Geographic Institute, University of Bern, 3012 Bern, Switzerland. Electronic address: benjamin.bandowe@giub.unibe.ch.
authors: Benjamin A Musa
authors: BAM
authors: Bandowe
authors: Soil Science Group, Geographic Institute, University of Bern, 3012 Bern, Switzerland.
authors: María Gómez
authors: MG
authors: Lueso
authors: Soil Science Group, Geographic Institute, University of Bern, 3012 Bern, Switzerland.
authors: Wolfgang
authors: W
authors: Wilcke
mesh_terms: D001372:Aza Compounds / Q000032:analysis* / Q000737:chemistry; D002947:Cities; D004784:Environmental Monitoring; D010100:Oxygen / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry; D018154:Slovakia; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry; D013548:Sweden; D013785:Thailand; D014329:Tropical Climate
chemical_list: D001372:Aza Compounds; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D010100:Oxygen
keywords: Azaarenes; Oxygenated PAHs; PAHs; Tropical climate; Tropical–temperate comparison; Urban soils