Μελέτη της κατανομής και της βιοδραστικότητας σωματιδιακών οργανικών ρύπων στην ατμόσφαιρα αστικών περιοχών

Abstract

The aim of this research was (1) to investigate the distribution of organic compounds associated with size segregated atmospheric aerosols, (2) to determine the redox activity and the mutagenicity of size-fractionated particulate matter (PM) and (3) to assess the role of organic species in generating these biological activities. More precisely, the concentrations of 18 PAHs, 2 NPAHs, 19 OCPs, 6 PCBs, 10 AHs and 2 isoprenoids compounds were determined in different size fractions. Seasonal variations of concentration levels, particle size distribution were also examined, so as to estimate their ambient environmental sources and to provide helpful information about the environmental levels of these harmful substances. Furthermore, the biological effects of size-separated PM were determined by measuring the mutagenicity using S.Typhimurium strains TA98 and TA100, with and without metabolic activation and the redox activity. Data form the biological tests were correlated with chemical data in order to elucidate the mutagenicity and the redox activity of size fractions as a result of the presence of the targeted compounds or not. Sample acquisition was carried out at an urban site of Thessaloniki, adjacent to a busy street, during winter (11-27 December 2007) and summer (3-27 June 2008). Particles were separated into five fractions (4 stages and a back up filter) resulting in size ranges of >7,5, 7,5-3,0, 3,0-1,5, 1,5-0,95, <0,95 μm. During the analytical procedure, organic extracts were fractionated using glass column chromatography and all 4 fractions eluted were divided into two parts for chemical analysis and biological assays. The main conclusions of this research could be summarised to the following: • Concentrations of PM and organic compounds The total PM calculated from all impactor stages were 127 μg m-3 in summer and 272 μg m-3 in winter, respectively. The concentration of PM was found to be highest at particle diameters <0,95 μm in both sampling campaigns. Significant seasonal variations were observed in particle size fractions 0,95-1,5 μm, 1,5-3,0 μm with the highest concentrations during the cold period. Total n-alkanes (sum of all size fractions), ΣΝΑ were 59,4 ng m-3 in summer and 123 ng m-3 in winter, respectively. The concentrations of ΣΝΑ and of several AHs in various size fractions were significantly higher in winter, reflecting inputs from central heating. ΣOCPs mean concentrations (sum of all size fractions) were 101 pg m-3 in summer and 217 pg m-3 in winter, respectively. ΣPCBs mean concentrations varied from 12 pg m-3 in the cold period to 93 pg m-3 in the warm period. The highest concentrations of these species were found on particles <0,95 μm in both sampling campaigns. Elevated levels of several of these compounds during summer are attributed to an increasing input of secondary sources e.g volatilization from environmental compartments. Total PAH concentrations (sum of all size fractions) ΣPAH, ranged from 8,54 ng m-3 in summer to 24,6 ng m-3 in winter, respectively. Seasonal variations were important for ΣPAH (particles <0,95 μm, 0,95-1,5 μm, TSP) and for several PAHs in the various size ranges with the highest concentrations found in winter period. Even though, the concentrations of ΣPAH in particles >7,5 μm were significantly higher in summer period.