Publications by authors named "Jan Hovorka"

14 Publications

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Spatial-temporal variability of aerosol sources based on chemical composition and particle number size distributions in an urban settlement influenced by metallurgical industry.

Environ Sci Pollut Res Int 2020 Nov 5;27(31):38631-38643. Epub 2020 Jul 5.

Department of Public Health Sciences, University of Rochester Medical Center, 265 Crittenden Boulevard, Rochester, NY, 14642-0708, USA.

The Moravian-Silesian region of the Czech Republic with its capital city Ostrava is a European air pollution hot spot for airborne particulate matter (PM). Therefore, the spatiotemporal variability assessment of source contributions to aerosol particles is essential for the successful abatement strategies implementation. Positive Matrix Factorization (PMF) was applied to highly-time resolved PM chemical composition (1 h resolution) and particle number size distribution (PNSD, 14 nm - 10 μm) data measured at the suburban (Ostrava-Plesná) and urban (Ostrava-Radvanice) residential receptor sites in parallel during an intensive winter campaign. Diel patterns, meteorological variables, inorganic and organic markers, and associations between the chemical composition factors and PNSD factors were used to identify the pollution sources and their origins (local, urban agglomeration and regional). The source apportionment analysis resolved six and four PM sources in Plesná and Radvanice, respectively. In Plesná, local residential combustion sources (coal and biomass combustion) followed by regional combustion sources (residential heating, metallurgical industry) were the main contributors to PM. In Radvanice, local residential combustion and the metallurgical industry were the most important PM sources. Aitken and accumulation mode particles emitted by local residential combustion sources along with common urban sources (residential heating, industry and traffic) were the main contributors to the particle number concentration (PNC) in Plesná. Additionally, accumulation mode particles from local residential combustion sources and regional pollution dominated the particle volume concentration (PVC). In Radvanice, local industrial sources were the major contributors to PNC and local coal combustion was the main contributor to PVC. The source apportionment results from the complementary datasets elucidated the relevance of highly time-resolved parallel measurements at both receptor sites given the specific meteorological conditions produced by the regional orography. These results are in agreement with our previous studies conducted at this site. Graphical abstract.
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http://dx.doi.org/10.1007/s11356-020-09694-0DOI Listing
November 2020

Nitrated monoaromatic hydrocarbons (nitrophenols, nitrocatechols, nitrosalicylic acids) in ambient air: levels, mass size distributions and inhalation bioaccessibility.

Environ Sci Pollut Res Int 2020 Jun 11. Epub 2020 Jun 11.

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.

Nitrated monoaromatic hydrocarbons (NMAHs) are ubiquitous in the environment and an important part of atmospheric humic-like substances (HULIS) and brown carbon. They are ecotoxic and with underresearched toxic potential for humans. NMAHs were determined in size-segregated ambient particulate matter collected at two urban sites in central Europe, Ostrava and Kladno, Czech Republic. The average sums of 12 NMAHs (ΣNMAH) measured in winter PM samples from Ostrava and Kladno were 102 and 93 ng m, respectively, and 8.8 ng m in summer PM samples from Ostrava. The concentrations in winter corresponded to 6.3-7.3% and 2.6-3.1% of HULIS-C and water-soluble organic carbon (WSOC), respectively. Nitrocatechols represented 67-93%, 61-73% and 28-96% of NMAHs in PM samples collected in winter and summer at Ostrava and in winter at Kladno, respectively. The mass size distribution of the targeted substance classes peaked in the submicrometre size fractions (PM), often in the PM size fraction especially in summer. The bioaccessible fraction of NMAHs was determined by leaching PM samples in two simulated lung fluids, Gamble's solution and artificial lysosomal fluid (ALF). More than half of NMAH mass is found bioaccessible, almost complete for nitrosalicylic acids. The bioaccessible fraction was generally higher when using ALF (mimics the chemical environment created by macrophage activity, pH 4.5) than Gamble's solution (pH 7.4). Bioaccessibility may be negligible for lipophilic substances (i.e. log K > 4.5).
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http://dx.doi.org/10.1007/s11356-020-09540-3DOI Listing
June 2020

Integration of air pollution data collected by mobile measurement to derive a preliminary spatiotemporal air pollution profile from two neighboring German-Czech border villages.

Sci Total Environ 2020 Jun 11;722:137632. Epub 2020 Mar 11.

Joint Mass Spectrometry Center, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; Joint Mass Spectrometry Center, Chair of Analytical Chemistry, University of Rostock, Rostock, Germany.

Generally, there are only a few fixed air quality monitoring stations installed in villages or rural areas and only a few studies on small-scale variations in air pollution have been described in detail, which make it difficult to estimate human exposure in such environments and related adverse health effects. Moreover, biomass combustion can be an important source of air pollution in rural areas, comparable to vehicle and industrial emissions in urban planning. And their air pollutants are mainly affected by local sources. For this reason, a survey on rural air pollution was carried out in this study. Therefore, portable, battery-powered monitoring devices were used to measure particulate matter (PM, PM, PM, particle number concentration, and black carbon) in order to study air quality in rural communities. The focus of the investigations was to explore the application of mobile monitoring equipment in small-scale environments, compare the differences in rural air pollutants between two neighboring villages in two countries, and the identification of pollution hotspots. The measurements were carried out in November 2018 in two villages on the German-Czech border. Over a period of four days, 21 mobile measurements along fixed routes were carried out simultaneously at both locations. The analysis of the data revealed significant differences in PN and PM concentrations in rural air pollutants between the two countries. The spatial and temporal distribution of air pollution hotspots in the Czech village was higher than that in the German village. The relationships between the measurement parameters were weak but highly significant and the meteorological parameters can effect air pollution. Overall, the results of this study show that mobile measurements are suitable for effectively recording and distinguishing spatial and temporal characteristics of air quality.
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http://dx.doi.org/10.1016/j.scitotenv.2020.137632DOI Listing
June 2020

Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons in Ambient Air-Levels, Phase Partitioning, Mass Size Distributions, and Inhalation Bioaccessibility.

Environ Sci Technol 2020 03 11;54(5):2615-2625. Epub 2020 Feb 11.

Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany.

Among the nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are some of the most hazardous substances to public health, mainly because of their carcinogenicity and oxidative potential. Despite these concerns, the concentrations and fate of NPAHs and OPAHs in the atmospheric environment are largely unknown. Ambient air concentrations of 18 NPAHs, 5 quinones, and 5 other OPAHs were determined at two urban and one regional background sites in central Europe. At one of the urban sites, the total (gas and particulate) concentrations of ΣOPAHs were 10.0 ± 9.2 ng/m in winter and 3.5 ± 1.6 ng/m in summer. The gradient to the regional background site exceeded 1 order of magnitude. ΣNPAH concentrations were typically 1 order of magnitude lower than OPAHs. Among OPAHs, 9-fluorenone and (9,10)-anthraquinone were the most abundant species, accompanied by benzanthrone in winter. (9,10)-Anthraquinone represented two-thirds of quinones. We found that a large fraction of the target substance particulate mass was carried by submicrometer particles. The derived inhalation bioaccessibility in the PM size fraction is found to be ≈5% of the total ambient concentration of OPAHs and up to ≈2% for NPAHs. For 9-fluorenone and (9,10)-anthraquinone, up to 86 and 18%, respectively, were found at the rural site. Our results indicate that water solubility could function as a limiting factor for bioaccessibility of inhaled particulate NPAHs and OPAHs, without considerable effect of surfactant lipids and proteins in the lung lining fluid.
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http://dx.doi.org/10.1021/acs.est.9b06820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307896PMC
March 2020

The influence of local emissions and regional air pollution transport on a European air pollution hot spot.

Environ Sci Pollut Res Int 2019 Jan 17;26(2):1675-1692. Epub 2018 Nov 17.

Department of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v.v.i, Rozvojová 1/135, 165 02, Prague 6 - Suchdol, Czech Republic.

The EU air quality standards have been frequently exceeded in one of the European air pollution hot spots: Ostrava. The aim of this study was to perform an air quality comparison between an urban site (Radvanice), which has a nearby metallurgical complex, and a suburban site (Plesná) to estimate air pollution sources and determine their local and/or regional origins. Twenty-four hour PM and PM (particular matter) concentrations, detailed mass size distributions (MSDs) to distinguish the sources of the fine and coarse PM, and their chemical compositions were investigated in parallel at both sites during the winter of 2014. Positive matrix factorization (PMF) was applied to the PM and PM chemical compositions to investigate their sources. During the measurement campaign, prevailing northeastern-southwestern (NE-SW) wind directions (WDs) were recorded. Higher average PM concentration was measured in Radvanice than in Plesná, whereas PM concentrations were similar at both sites. A source apportionment analysis revealed six and five sources for PM and PM, respectively. In Radvanice, the amount of PM and the most chemical species were similar under SW and NE WD conditions. The dominant sources were industrial (43% for PM and 27% for PM), which were caused by a large metallurgical complex located to the SW, and biomass burning (25% for PM and 36% for PM). In Plesná, the concentrations of PM and all species significantly increased under NE WD conditions. Secondary inorganic aerosols were dominant, with the highest contributions deriving from the NE WD. Therefore, regional pollution transport from the industrial sector in Silesian Province (Poland) was evident. Biomass burning contributed 22% and 24% to PM and PM, respectively. The air quality in Ostrava was influenced by local sources and regional pollution transport. The issue of poor air quality in this region is complex. Therefore, international cooperation from both states (the Czech Republic and Poland) is needed to achieve a reduction in air pollution levels.
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http://dx.doi.org/10.1007/s11356-018-3670-yDOI Listing
January 2019

New comprehensive approach for airborne asbestos characterisation and monitoring.

Environ Sci Pollut Res Int 2018 Oct 30;25(30):30488-30496. Epub 2018 Aug 30.

Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, 12801, Prague 2, Czech Republic.

High concentrations of airborne asbestos in the ambient air are still a serious problem of air quality in numerous localities around the world. Since 2002, elevated concentrations of asbestos minerals of unknown origin have been detected in the ambient air of Pilsen, Czech Republic. To determine the asbestos fibre sources in this urban air, a systematic study was conducted. First, 14 bulk dust samples were collected in Pilsen at nine localities, and 6 bulk samples of construction aggregates for gravel production were collected in a quarry in the Pilsen-Litice district. The quarry is the largest quarry in the Pilsen region and the closest quarry to the built-up urban area. X-ray diffraction of the asbestos minerals revealed that monoclinic amphibole (MA, namely actinolite based on subsequent SEM-EDX analysis) in the bulk samples accounted for < 1-33% of the mass and that the highest values were found in the bulk dust samples from the railway platform of the Pilsen main railway station. Simultaneously, 24-h samples of airborne particulate matter (PM) at three localities in Pilsen were collected. Actinolite was identified in 40% of the PM samples. The relationship between the meteorology and presence of actinolite in the 24 PM samples was not proven, probably due to the long sampling integration time. Therefore, highly time-and-size-resolved PM sampling was performed. Second, sampling of size-segregated aerosols and measurements of the wind speed (WS), wind direction (WD), precipitation (P) and hourly PM, PM and PM were conducted in a suburban locality near the quarry in two monthly highly time-resolved periods (30, 60, 120 min). Three/eight PM size fractions were sampled by a Davis Rotating-drum Uniform-size-cut Monitor (3/8DRUM) and analysed for the presences of asbestos fibres by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX). Asbestos fibre detection in highly time-resolved PM samples and current WD and WS determination allows the apportionment directionality of asbestos fibre sources. The number of critical actinolite asbestos fibres (length ≥ 5 μm and width < 3 μm, 3:1) increased with the PM/PM and PM/PM ratios, WS > 2 m s and precipitation < 1 mm. Additionally, the number of critical actinolite asbestos fibres was not related to a specific WD. Therefore, we conclude that the sources of airborne critical actinolite asbestos fibres in Pilsen's urban area are omnipresent. Frequent use of construction aggregates and gravel from the metamorphic spilite quarries in the Pilsen region and in many localities around the urban area is a plausible explanation for the omnipresence of the critical actinolite asbestos fibres concentration in Pilsen's ambient air. Mitigation strategies to reduce the concentrations of critical actinolite asbestos fibres must be developed. Continuous monitoring and performing SEM-EDX analysis of highly time-and-size-resolved PM samples, correlated with fast changing WS and WD, seems to be a strong tool for efficiently controlling the mitigation strategies of critical actinolite asbestos fibres.
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http://dx.doi.org/10.1007/s11356-018-2791-7DOI Listing
October 2018

Source apportionment of aerosol particles at a European air pollution hot spot using particle number size distributions and chemical composition.

Environ Pollut 2018 Mar 22;234:145-154. Epub 2017 Nov 22.

Center for Air Resources Engineering and Science, Clarkson University, Potsdam, NY 13699-5708, USA; Department of Public Health Sciences, University of Rochester Medical Center, Rochester, NY, USA.

Ostrava in the Moravian-Silesian region (Czech Republic) is a European air pollution hot spot for airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and ultrafine particles (UFPs). Air pollution source apportionment is essential for implementation of successful abatement strategies. UFPs or nanoparticles of diameter <100 nm exhibit the highest deposition efficiency in human lungs. To permit apportionment of PM sources at the hot-spot including nanoparticles, Positive Matrix Factorization (PMF) was applied to highly time resolved particle number size distributions (NSD, 14 nm-10 μm) and PM chemical composition. Diurnal patterns, meteorological variables, gaseous pollutants, organic markers, and associations between the NSD factors and chemical composition factors were used to identify the pollution sources. The PMF on the NSD reveals two factors in the ultrafine size range: industrial UFPs (28%, number mode diameter - NMD 45 nm), industrial/fresh road traffic nanoparticles (26%, NMD 26 nm); three factors in the accumulation size range: urban background (24%, NMD 93 nm), coal burning (14%, volume mode diameter - VMD 0.5 μm), regional pollution (3%, VMD 0.8 μm) and one factor in the coarse size range: industrial coarse particles/road dust (2%, VMD 5 μm). The PMF analysis of PM revealed four factors: SIA/CC/BB (52%), road dust (18%), sinter/steel (16%), iron production (16%). The factors in the ultrafine size range resolved with NSD have a positive correlation with sinter/steel production and iron production factors resolved with chemical composition. Coal combustion factor resolved with NSD has moderate correlation with SIA/CC/BB factor. The organic markers homohopanes correlate with coal combustion and the levoglucosan correlates with urban background. The PMF applications to NSD and chemical composition datasets are complementary. PAHs in PM were found to be associated with coal combustion factor.
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http://dx.doi.org/10.1016/j.envpol.2017.10.097DOI Listing
March 2018

Source Impact Determination using Airborne and Ground Measurements of Industrial Plumes.

Environ Sci Technol 2016 09 1;50(18):9881-8. Epub 2016 Sep 1.

Department of Chemistry and Toxicology, Veterinary Research Institute , Hudcova 296/70, 621 00 Brno, Czech Republic.

Industrial particulate matter (PM) air pollution exposing nearby residential areas forms several European air pollution hot-spots. One of these hot-spot is the residential district of Ostrava Radvanice-Bartovice with frequent exceedances for PM and benzo[a]pyrene B[a]P, a carcinogenic polycyclic aromatic hydrocarbon (PAH) of MW > 228 amu. Such PAHs are highly bonded to the ultrafine particles (UFPs), the smallest PM size fraction, which deposits most efficiently in the alveolar region of human lungs. Airborne measurements identified UFP point sources in the adjacent metallurgical complex and mapped limited horizontal and vertical dispersion of industrial plumes enriched with UFPs (3.2 × 10(5)cm(-3)). The plumes, episodes of simultaneous peaks of UFPs (1.4 × 10(5)cm(-3)), SO2 (88.2 ppb), and CO (11.3 ppm), were recorded on the ground downwind in the residential district when wind speeds >1 ms(-1). In the plumes, UFPs were mostly 19-44 nm in diameter, enriched with PAHs/B[a]P up to 43.8/3.5 mg·g(-1). Electron microscopy showed that these plume UFPs were mostly agglomerates of spherules of 30-50 nm in diameter. These source impact measurements, that combine airborne and ground-level measurements, are applicable to clearly identify specific industrial air pollution sources and provide information to assess their possible impact to human health in similar hot-spots worldwide.
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http://dx.doi.org/10.1021/acs.est.6b02304DOI Listing
September 2016

Day-to-day variability of toxic events induced by organic compounds bound to size segregated atmospheric aerosol.

Environ Pollut 2015 Jul 26;202:135-45. Epub 2015 Mar 26.

Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic. Electronic address:

This study quantified the temporal variability of concentration of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs), genotoxicity, oxidative DNA damage and dioxin-like activity of the extractable organic matter (EOM) of atmospheric aerosol particles of aerodynamic diameter (dae, μm) coarse (1 < dae < 10), upper- (0.5 < dae < 1) and lower-accumulation (0.17 < dae < 0.5) and ultrafine (<0.17) fractions. The upper accumulation fraction formed most of the aerosol mass for 22 of the 26 study days and contained ∼44% of total c-PAHs, while the ultrafine fraction contained only ∼11%. DNA adduct levels suggested a crucial contribution of c-PAHs bound to the upper accumulation fraction. The dioxin-like activity was also driven primarily by c-PAH concentrations. In contrast, oxidative DNA damage was not related to c-PAHs, as a negative correlation with c-PAHs was observed. These results suggest that genotoxicity and dioxin-like activity are the major toxic effects of organic compounds bound to size segregated aerosol, while oxidative DNA damage is not induced by EOM.
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http://dx.doi.org/10.1016/j.envpol.2015.03.024DOI Listing
July 2015

Ultrafine particles are not major carriers of carcinogenic PAHs and their genotoxicity in size-segregated aerosols.

Mutat Res 2013 Jun 1;754(1-2):1-6. Epub 2013 Mar 1.

Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine, AS CR, Prague, Czech Republic.

Some studies suggest that genotoxic effects of combustion-related aerosols are induced by carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) and their derivatives, which are part of the organic fraction of the particulate matter (PM) in ambient air. The proportion of the organic fraction in PM is known to vary with particle size. The ultrafine fraction is hypothesized to be the most important carrier of c-PAHs, since it possesses the highest specific surface area of PM. To test this hypothesis, the distribution of c-PAHs in organic extracts (EOMs) was compared for four size fractions of ambient-air aerosols: coarse (1
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http://dx.doi.org/10.1016/j.mrgentox.2012.12.016DOI Listing
June 2013

Association of size-resolved number concentrations of particulate matter with cardiovascular and respiratory hospital admissions and mortality in Prague, Czech Republic.

Inhal Toxicol 2010 Dec 18;22 Suppl 2:21-8. Epub 2010 Aug 18.

Charles University in Prague, Faculty of Science, Czech Republic.

We analyzed the association of particle number and PM(2.5) concentrations with mortality and cardiorespiratory hospital admissions in Prague. Number concentrations of submicron particles in the range of 15-487 nm were measured continuously at a central site in 2006. The particle number concentrations were integrated into four groups with count median diameters of 31 (NC(31)), 128 (NC(128)), and 346 nm (NC(346)). The total number concentration of submicron particles 15-487 nm (NC(tot)) was also constructed. The studied health outcomes were the daily hospital admissions due to cardiovascular and respiratory diseases and daily cardiovascular and respiratory mortality and the total mortality. The Poisson regression was used for data analysis. The strongest association was found for the accumulation mode particles (NC(346)) (RR 1.164, 95% CI: 1.052-1.287 for cardiovascular and 1.334, 95% CI: 1.126-1.579 for respiratory admissions for a 7-day moving average for 1000 particles per 1 cm(3) increase). Reasonable association between both the cardiovascular and respiratory admissions and NC(346) was also found for lag 0, lag 1, lag 2 (not for respiratory admissions), and the 4-day moving average. For NC(128) and NC(tot), the association was also significant for both cardiovascular and respiratory admissions at lag 0, lag 1, and lag 2 (not for respiratory admissions) for the 4-day and 7-day moving average. The association between the PM(2.5) and daily cardiovascular hospital admissions was significant at 2-day lag and for a 4-day average. Positive association with respiratory admissions was significant only for a 7-day average. No association was found between the studied air pollution variables and daily mortality.
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http://dx.doi.org/10.3109/08958378.2010.504758DOI Listing
December 2010

An acellular assay to assess the genotoxicity of complex mixtures of organic pollutants bound on size segregated aerosol. Part II: oxidative damage to DNA.

Toxicol Lett 2010 Oct 23;198(3):312-6. Epub 2010 Jul 23.

Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, v.v.i., Videnska 1083, 142 20 Prague, Czech Republic.

Ambient air particulate matter (atmospheric aerosol; PM) is an important factor in the development of various diseases. Oxidative stress is believed to be one of the mechanisms of action of PM on the human organism. The aim of our study was to investigate the ability of organic extracts of size segregated aerosol particles (EOM; three fractions of aerodynamic diameter 1-10μm, 0.5-1μm and 0.17-0.5μm) to induce oxidative damage to DNA in an in vitro acellular system of calf thymus (CT) DNA with and without S9 metabolic activation. PM was collected in the Czech Republic at four places with different levels of air pollution. Levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) tended to increase with decreasing sizes of PM. S9 metabolic activation increased the oxidative capacity of PM; mean levels of 8-oxodG/10(5) dG per 1000m(3) of air for samples with and without metabolic activation were 0.093 and 0.067, respectively (p<0.05). When results of oxidative damage to DNA were normalized per microgram of aerosol mass, mean levels of 8-oxodG/10(5) dG were 0.265 and 0.191, for incubation with and without S9 fraction, respectively (p<0.05). We observed a significant positive association between concentrations of polycyclic aromatic hydrocarbons (c-PAHs) bound to PM and levels of 8-oxodG/10(5) dG per 1000m(3) of air after metabolic activation of EOM samples (R=0.695, p<0.05). The correlation was weaker and non-significant for samples without metabolic activation (R=0.523, p=0.08). In conclusion, we showed that organic extracts of PM were able to induce oxidative damage to DNA in vitro; this ability was increased after S9 metabolic activation of EOM and with decreasing sizes of PM.
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http://dx.doi.org/10.1016/j.toxlet.2010.06.021DOI Listing
October 2010

An acellular assay to assess the genotoxicity of complex mixtures of organic pollutants bound on size segregated aerosol. Part I: DNA adducts.

Toxicol Lett 2010 Oct 30;198(3):304-11. Epub 2010 Jun 30.

Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, v.v.i., Prague, Czech Republic.

An acellular assay consisting of calf thymus DNA with/without rat liver microsomal S9 fraction was used to study the genotoxicity of complex mixtures of organic air pollutants bound to size segregated aerosols by means of DNA adduct analysis. We compared the genotoxicity of the organic extracts (EOMs) from three size fractions of aerosol ranging from 0.17μm to 10μm that were collected by high volume cascade impactors in four localities of the Czech Republic differing in the extent of the environmental pollution: (1) small village in proximity of a strip mine, (2) highway, (3) city center of Prague and (4) background station. The total DNA adduct levels induced by 100μg/ml of EOMs were analyzed by (32)P-postlabelling analysis with a nuclease P1 method for adduct enrichment. The main finding of the study was most of the observed genotoxicity was connected with a fine particulate matter fraction (<1μm). The concentrations of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in EOMs indicate that fine fractions (0.5-1μm) bound the highest amount of c-PAHs in all aerosol sampling sites, which might be related to the higher specific surface of this fraction as compared with a course fraction (1-10μm) and higher mass as compared with a condensational fraction (0.17-0.5μm). As for aerosol mass, both fine and condensational fractions are effective carriers of c-PAHs. Similarly, the DNA adduct levels per m(3) of air were highest for the fine fraction, while the condensational fraction (strip mine site and city center) revealed the highest DNA adduct levels in cases where aerosol mass is taken into consideration. A strong correlation was found between the c-PAHs and DNA adduct levels induced by EOMs in all the localities and for various size fractions (R(2)=0.98, p<0.001). It may be concluded that the analysis of total DNA adducts induced in an acellular assay with/without metabolic activation represents a relatively simple method to assess the genotoxic potential of various complex mixtures.
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http://dx.doi.org/10.1016/j.toxlet.2010.06.016DOI Listing
October 2010

Origin of lead in eight Central European peat bogs determined from isotope ratios, strengths, and operation times of regional pollution sources.

Environ Sci Technol 2003 Feb;37(3):437-45

Department of Geochemistry, Czech Geological Survey, Geologická 6, 152 00 Prague 5, Czech Republic.

Lead originating from coal burning, gasoline burning, and ore smelting was identified in 210Pb-dated profiles through eight peat bogs distributed over an area of 60,000 km2. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering with Germany, Austria, and Poland. Basal peat 14C-dated at 11,000 years BP had a relatively high 206Pb/207Pb ratio (1.193). Peat deposited around 1800 AD had a lower 206Pb/207Pb ratio of 1.168-1.178, indicating that environmental lead in Central Europe had been largely affected by human activity (smelting) even before the beginning of the Industrial Revolution. Five of the sites exhibited a nearly constant 206Pb/207Pb ratio (1.175) throughout the 19th century, resembling the "anthropogenic baseline" described in Northern Europe (1.17). At all sites, the 206Pb/207Pb ratio of peat decreased at least until 1980; at four sites, a reversal to more radiogenic values (higher 206Pb/207Pb), typical of easing pollution, was observed in the following decade (1980-1990). A time series of annual outputs for 14 different mining districts dispersing lead into the environment has been constructed for the past 200 years. The production of Ag-Pb, coal, and leaded gasoline peaked in 1900, 1980, and 1980, respectively. In contrast to other European countries, no peak in annual Pb accumulation rates was found in 1900, the year of maximum ore smelting. The highest annual Pb accumulation rates in peat were consistent with the highest Pb emission rates from coal-fired power plants and traffic (1980). Although maximum coal and gasoline production coincided in time, their isotope ratios were unique. The mean measured 206Pb/207Pb ratios of local coal, ores, and gasoline were 1.19, 1.16, and 1.11, respectively. A considerable proportion of coal emissions, relative to gasoline emisions, was responsible for the higher 206Pb/207Pb ratios in the recent atmosphere (1.15) compared to Western Europe (1.10). As in West European countries, the gasoline sold in the Czech Republic during the Communist era (1948-1989) contained an admixture of low-radiogenic Precambrian lead from Australia.
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http://dx.doi.org/10.1021/es0200387DOI Listing
February 2003