Genotoxicity of environmental air pollution in three European cities: Prague, Kosice and Sofia.
The genotoxic potential of extractable organic matter (EOM) associated with the respirable particulate matter (PM <10 microm) of atmospheric pollution has been determined in three European cities--Prague (Czech Republic, two monitoring sites, Libus and Smíchov), Kosice (Slovak Republic) and Sofia (Bulgaria) using the alkaline single-cell gel electrophoresis (the comet assay). The EOM samples were extracted by dichloromethane from ambient airborne particles collected daily (24 h intervals) during 3-month sampling periods in winter and summer seasons. The human metabolically competent cell line Hep G2 was used as a test system and benzo[a]pyrene (BaP), a known carcinogen, was applied as a positive control (internal standard) in each electrophoretic run. Two-hour exposure of Hep G2 cells to equivalent EOM concentrations ranging from 5 to 150 microg EOM/ml resulted in a linear dose-dependent increase of DNA migration (r > 0.9, P < 0.01). A less significant dose-response (r = 0.61) was only induced by the EOM sample from the locality Prague-Libus (PRG-LB) in the winter. Generally, a 1.5 to four-fold increase of DNA strand breaks over the background control level was determined in EOM-exposed cells. In order to compare the genotoxic potential of individual EOMs, a mathematical model was used to correct the 'real' data. No substantial location- or season-related differences were found in EOM genotoxicity (EOM microg/ml), except for the EOM sample from Sofia, collected in the summer. This EOM sample induced a nearly two-fold lower level of DNA damage in comparison with other EOMs. On the other hand, clear statistically significant location- and season-related differences (P < 0.001) in ambient air genotoxicity were determined when the EOM quantity per cubic meter of air (microg/m3) was taken into account. In that case, the genotoxicity of winter air pollution was six- to 10-fold higher in comparison with summer air. The air pollution genotoxicity in individual localities rose during the winter season in the order: PRG-LB < Kosice < Prague-Smíchov (PRG-SM) < Sofia, while during the summer season the highest ambient air genotoxicity was revealed in the locality Prague-Smíchov and approximately equal air pollution genotoxicity was determined among localities Prague-Libus, Kosice and Sofia (PRG-LB approximately Kosice approximately Sofia < PRG-SM). The greatest overall air pollution genotoxicity was determined in the locality Sofia during the winter season. In a time course study to evaluate the kinetics of DNA strand break rejoining it was shown that the level of DNA strand breaks in EOM-exposed cells has returned to near the background level within 24 h after the treatment.
Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava, Slovak Republic. alena.gabelova@savba.sk
Alena
A
Gábelová
Zuzana
Z
Valovicová
Eva
E
Horváthová
Darina
D
Slamenová
Blanka
B
Binková
Radim J
RJ
Srám
Peter B
PB
Farmer
D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution; D001564:Benzo(a)pyrene / Q000633:toxicity; D002031:Bulgaria; D002273:Carcinogens / Q000633:toxicity; D045744:Cell Line, Tumor; D002947:Cities; D020552:Comet Assay; D018153:Czech Republic; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004260:DNA Repair; D006801:Humans; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009930:Organic Chemicals / Q000633:toxicity*; D012621:Seasons; D018154:Slovakia
D000393:Air Pollutants; D002273:Carcinogens; D009153:Mutagens; D009930:Organic Chemicals; D001564:Benzo(a)pyrene; D004247:DNA