Affiner votre recherche
Résultats 1441-1450 de 1,535
An integrated approach to identify the origin of PM10 exceedances
2012
Amodio, M. | Andriani, E. | de Gennaro, G. | Demarinis Loiotile, A. | Di Gilio, A. | Placentino, M. C.
PURPOSE: This study was aimed to the development of an integrated approach for the characterization of particulate matter (PM) pollution events in the South of Italy. METHODS: PM10 and PM2.5 daily samples were collected from June to November 2008 at an urban background site located in Bari (Puglia Region, South of Italy). Meteorological data, particle size distributions and atmospheric dispersion conditions were also monitored in order to provide information concerning the different features of PM sources. RESULTS: The collected data allowed suggesting four indicators to characterize different PM10 exceedances. PM2.5/PM10 ratio, natural radioactivity, aerosol maps and back-trajectory analysis and particle distributions were considered in order to evaluate the contribution of local anthropogenic sources and to determine the different origins of intrusive air mass coming from long-range transport, such as African dust outbreaks and aerosol particles from Central and Eastern Europe. The obtained results were confirmed by applying principal component analysis to the number particle concentration dataset and by the chemical characterization of the samples (PM10 and PM2.5). CONCLUSIONS: The integrated approach for PM study suggested in this paper can be useful to support the air quality managers for the development of cost-effective control strategies and the application of more suitable risk management approaches.
Afficher plus [+] Moins [-]Influence of sampling sufficiency on biodiversity analysis of microperiphyton communities for marine bioassessment
2012
Xu, Henglong | Zhang, Wei | Jiang, Yong | Zhu, Mingzhuang | Al-Rasheid, Khaled A. S.
INTRODUCTION: With quick responses to environmental changes, easy sampling, relative immobility, increasing availability of easily used taxonomic references, and allowing standardization for temporal and spatial comparisons, the biodiversity measures of microperiphyton communities have widely been accepted as useful indicators to evaluate environmental stress and anthropogenic impact. MATERIALS AND METHODS: The influence of sampling sufficiency for biodiversity analysis of microperiphyton communities was studied using a range of statistical methods in coastal waters of the Yellow Sea, northern China, from May to June 2010. Samples were collected from two depths using an artificial substrate. RESULTS: Sampling sizes represented a significant influence on biodiversity analysis of microperiphyton communities, e.g., 20 slide replicates (350 cm2) were sufficient for the microperiphyton communities at both depths, while 10 slide replicates (175 cm2) could meet the sampling strategy only for the samples with colonization times of 10 days or more at a depth of 1 m for recovering 90% species during the study period. Otherwise, more slide replicates were required with the increase of water depths and shortening colonization times for recovering microperiphyton species, e.g., for recovering 90% species of a “mature” microperiphyton community (>10 days), ∼10 slide replicates (∼175 cm2) were sufficient at a depth of 1 m, while for the “young” samples (>10 days) much more (15–30) slide replicates were required at both depths in this study. Furthermore, to achieve <10% standard errors, six (105 cm2) and nine (∼160 cm2) slide replicates were required for biodiversity analysis of the microperiphyton communities with various colonization times at depths of 1 and 3 m during the summer season, respectively. CONCLUSION: These results suggest that sampling sizes represented a significant influence on biodiversity analysis of microperiphyton communities for monitoring programs and ecological conservation researches in marine ecosystems.
Afficher plus [+] Moins [-]Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana
2012
Adu-Kumi, Sam | Kareš, Radovan | Literák, Jaromír | Borůvková, Jana | Yeboah, Philip O. | Carboo, Derick | Akoto, Osei | Darko, Godfred | Osae, Shiloh | Klánová, Jana
Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p′- and p,p′-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m−3 (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p′-DDT/p,p′-DDE ratio suggested recent inputs of fresh technical DDT.
Afficher plus [+] Moins [-]Evaluation of air quality by passive and active sampling in an urban city in Turkey: current status and spatial analysis of air pollution exposure
2012
Gaga, Eftade O. | Döğeroğlu, Tuncay | Özden, Özlem | Ari, Akif | Yay, Ozan Devrim | Altuğ, Hicran | Akyol, Nesimi | Örnektekin, Sermin | Van Doorn, Wim
Concentrations of air pollutants, nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter (PM2.5 and PM10), trace metals, and polycyclic aromatic hydrocarbons (PAHs) were measured in 2008 and 2009 in the city of Eskişehir, central Turkey. Spatial distributions of NO2, SO2, and ozone were determined by passive sampling campaigns carried out during two different seasons with fairly large spatial coverage. A basic population exposure assessment was carried out employing Geographical Information System techniques by combining population density maps with pollutant distribution maps of NO2 and SO2. It was found that 95 % of the population is exposed to NO2 levels close to the World Health Organization guideline value. Regarding SO2, a large proportion of the population (83 %) is exposed to levels above the WHO second interim target value. Concentrations of all the pollutants showed a seasonal pattern increasing in winter period, except for ozone having higher concentrations in summer season. Daily PM10 and PM2.5 concentrations exceeded European Union limit values almost every sampling day. Toxic fractions of the measured PAHs were calculated and approximately fourfold increase was observed in winter period. Copper, Pb, Sn, As, Cd, Zn, Sb, and Se were found to be moderately to highly enriched in PM10 fraction, indicating anthropogenic input to those elements measured. Exposure assessment results indicate the need for action to reduce pollutant emissions especially in the city center. Passive sampling turns out to be a practical and economical tool for air quality assessment with large spatial coverage.
Afficher plus [+] Moins [-]Metal pollution does not bias offspring sex ratio in great tit (Parus major)
2012
Eeva, Tapio | Sillanpää, Saila | Lehikoinen, Esa
PURPOSE: We measured offspring sex ratios in a resident insectivorous passerine bird, the Great tit Parus major, to find out whether metal pollution around a Finnish copper smelter would bias sex ratios in this territorial forest bird species. Besides a direct effect of pollutants, we were interested in possible indirect effects of pollution-related resource limitation, i.e., changes in food quality and quantity, on sex ratio. METHODS: We manipulated the diet quantity and quality (carotenoid levels) of P. major nestlings in polluted and unpolluted environments to find out if variation in dietary resource levels has any effect on fledgling sex ratios. Faecal metal levels of nestlings were analysed to monitor the level of pollution exposure at each territory. Near the time of fledging (at the age of 15 days), feather samples were collected for molecular sex determination. RESULTS: We did not find any association between metal exposure levels and offspring sex ratio, and thus, our results do not support the hypothesis that metal pollution would have direct effects on P. major offspring sex ratio. We found that, irrespective of pollution level, high nestling mortality was associated with male-biased sex ratio, most likely due to sex-specific mortality. Our feeding treatment, however, showed no significant effects on offspring sex ratio, possibly because natural variation in food availability outweighed the effect of our food manipulation on nestling mortality. CONCLUSIONS: We conclude that metal exposure at the levels found in our study area does not bias fledgling sex ratios in this species, but biased sex ratios may follow under natural or pollution-related resource limitation.
Afficher plus [+] Moins [-]Effect directed analysis and mixture effects of estrogenic compounds in a sediment of the river Elbe
2012
Schmitt, Sebastian | Reifferscheid, Georg | Claus, Evelyn | Schlüsener, Michael | Buchinger, Sebastian
INTRODUCTION: Endocrine disrupting chemicals (EDCs) are present in the environment and can have serious effects on humans and wildlife. For the establishment of environmental quality guidelines and regulation of EDCs, a better understanding and knowledge of the occurrence and the behavior of environmental EDCs is necessary. The aim of the present study was to comprehensively identify substances that are responsible for the estrogenic effect of an environmental sediment sample taken from the river Elbe/Germany. DISCUSSION: The estrogenic effect of the organic sediment extract was determined using the yeast–estrogen–screen (YES). The sample was fractionated by liquid chromatography (LC) for effect directed analysis. The composition of estrogen-active fractions was further investigated by gas chromatography–mass spectrometry and high-resolution LC–MS analysis. The composition of the environmental sample was rebuilt with pure compounds in order to assess the partition of estrogenic activity caused by the identified compounds. The organic sediment extract showed an estrogenic potential of 1.9 ± 0.4 ng/g ethinylestradiol equivalents in the sediment. The most prominent contaminants with an estrogenic potential were 17β-estradiol, estrone, and 4-iso-nonylphenols, but other xenoestrogens like bisphenol A and stigmasterol could be found as well. A rebuild of the sample was measured in the YES in order to investigate mixture effects. About 67 % of the observed estrogenic effect in the sediment extract could be explained by a mixture which contained all identified compounds. Chlorophene (o-benzyl-p-chlorophenol)—a widely used antiseptic that was also identified in the sediment extract—has xenoestrogenic properties in the YES that are in the range of other xenoestrogens like 4-n-nonylphenol. This is the first report on chlorophene acting as a xenoestrogen.
Afficher plus [+] Moins [-]Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans
2012
Cakici, Ozlem | Akat, Esra
BACKGROUND, AIM AND SCOPE: Due to their ecological niche and insectivore nature, lizards are of increased risk of exposure to pesticides in agricultural areas. In addition to their potential direct effects on non-target species, insecticides can also result in indirect impacts on lizard population by reducing their food source. Carbaryl is a common insecticide that is widely used in areas of Turkey that are home to a variety of reptiles. However, to date, little is known about the potential effects of the exposure of reptiles such as lizards or snakes to this pesticide. The aim of the study was to investigate toxic effects of carbaryl on the testes of snake-eyed lizard, Ophisops elegans that is common to regions in Turkey where Carbaryl is applied and that it can be easily cultured in the laboratory. MATERIAL AND METHODS: Adult male lizards were exposed to carbaryl once by oral gavage in concentrations of 2.5, 25 and 250 μg/g. After 96 h, lizards were euthanized and dissected. Histopathological changes were detected by randomly counting 100 tubules in each lizard. Seminiferous tubules were categorized as normal, sloughing and disorganized tubules. Diameters of tubules were also measured. The differences in histopathological changes and tubule diameters were compared for statistical significance by one-way ANOVA, using SPSS 16.0. RESULTS AND DISCUSSION: Histopathological changes were more prominent in medium- (25 μg/g) and high-dose (250 μg/g) groups than in the low-dose (2.5 μg/g) group. In the medium-dose group, the hexagonal appearance of most tubules disappeared, and they took on an oval shape. Sloughing was the characteristic tubule appearance of the medium group. In the high-dose group, significant increases in the number of disorganized tubules and prominence of haemorrhages was observed. CONCLUSION: Carbaryl caused histopathological defects on the testes of O. elegans, so it is clear that carbaryl affects male fertility in O. elegans.
Afficher plus [+] Moins [-]Spatial distribution of illicit drugs in surface waters of the natural park of Pego-Oliva Marsh (Valencia, Spain)
2012
Vazquez-Roig, Pablo | Andreu, Vicente | Blasco, Cristina | Morillas, Francisco | Picó, Yolanda
BACKGROUND, AIM AND SCOPE: The Pego-Oliva Marsh is the second most important wetland in the Valencian Community (Spain). It is included in the RAMSAR agreement and represents one key point for migratory birds. Emerging contaminants from the human pressure, such as pharmaceuticals, illicit drugs and personal care product, are not included in the list of priority contaminants of the Water Framework Directive yet, and are neither monitored nor controlled. However, pollution of emerging contaminants can threaten the environment and even human health. In order to understand the status of the emerging contamination and recommend future rationalization of countermeasures, the occurrence of illicit drugs was investigated. MATERIAL AND METHODS: Samples were collected at 23 sites from the main irrigation channels and the marsh. Illicit drugs were extracted using solid phase extraction and determined by liquid chromatography tandem mass spectrometry. The method detection limits ranged from 0.01 to 1.54 ng l−1 and the recoveries from 57% to 120%. RESULTS AND DISCUSSION: 3,4-Methylenedioxymethamphetamine, ketamine, morphine, benzoylecgonine, cocaine, methadone, 6-acetylmorphine and nor-9-carboxy-tetrahydrocannabinol were detected. The mean concentrations were 0.62, 21.33, 1.30, 1.92, 2.25, 0.32, 0.04 and 0.07 ng l−1, respectively. The highest concentrations were in the north of Pego-Oliva Marsh. CONCLUSIONS: The pollution status by illicit drugs of the Pego-Oliva Marsh has been established. However, contamination levels in all the area of the natural park were low compared with those reported in other superficial waters.
Afficher plus [+] Moins [-]Kinetics and equilibrium properties of the biosorption of Cu2+ by algae
2012
Wang, Qiong | Peckenham, John | Pinto, Jamie | Patterson, Howard
The purpose of this study was to examine the kinetics and equilibrium properties of freshwater algae with Cu2+. This was a model system to explore using algae as biosensors for water quality. Methods included making luminescence measurements (fluorescence) and copper ion-selective electrode (CuISE) measurements vs. time to obtain kinetic data. Results were analyzed using a pseudo-first-order model to calculate the rate constants of Cu2+ uptake by algae: k p(Cu–algae) = 0.0025 ± 0.0006 s−1 by CuISE and k p(Cu–algae) = 0.0034 ± 0.0011 s−1 by luminescence. The binding constant of Cu–algae, K Cu–algae, was 1.62 ± 0.07 × 107 M−1. Fluorescence results analyzed using the Stern–Volmer relationship indicate that algae have two types of binding sites of which only one appears to affect quenching. The fluorescence-based method was found to be able to detect the reaction of algae with Cu2+ quickly and at a detection limit of 0.1 mg L−1.
Afficher plus [+] Moins [-]Lead concentration increase in the hepatic and gill soluble fractions of European chub (Squalius cephalus)—an indicator of increased Pb exposure from the river water
2012
Dragun, Zrinka | Krasnići, Nesrete | Strižak, Željka | Raspor, Biserka
PURPOSE: To examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1 μg L−1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2 μg L−1; EPCEU (Official J L 348:84, 2008)), would result in Pb accumulation in selected fish tissues. METHODS: Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia–Slovenia). RESULTS: At the site with increased dissolved Pb in the river water, soluble gill Pb levels (17.3 μg L−1) were approximately 20 times higher compared to uncontaminated sites (0.85 μg L−1), whereas the ratio between contaminated (18.1 μg L−1) and uncontaminated sites (1.17 μg L−1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex, or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects. CONCLUSIONS: The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters.
Afficher plus [+] Moins [-]