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931.
Przylibski TA Zebrowski A Karpińska M Kapała J Kozak K Mazur J Grządziel D Mamont-Cieśla K Stawarz O Kozłowska B Kłos B Dorda J Wysocka M Olszewski J Dohojda M 《Journal of environmental radioactivity》2011,102(8):735-741
The paper presents the results of year-long measurements of radon (222Rn) concentration inside 129 buildings in Poland in relation to the geological conditions of their foundation. The authors took into account the division of the country into tectonic units, as well as the lithology of the rocks forming the bedrock of these buildings. As expected, the highest value of mean annual 222Rn concentration (845 Bq/m3) was recorded in a building situated in the area of the Sudetes, while the highest geometric mean (characteristic of the expected log-normal data distribution) was calculated based on measurements from buildings located within the East-European craton, in the area of Mazury-Podlasie monocline, where it reached 231 Bq/m3. Such results reflect geological conditions - the occurrence of crystalline rocks (especially U- and Ra-enriched granites and orthogneisses) on the surface in the Sudetes, and of young post-glacial sediments containing fragments of Scandinavian crystalline rocks, also enriched with U and Ra, in the area of Mazury-Podlasie monocline. However, the least expected result of the investigations was finding out that, contrary to the hitherto widespread belief, none of the major tectonic units of Poland can be excluded from the list of those containing buildings with mean annual 222Rn concentration exceeding 200 Bq/m3. The mean annual concentration of radon for all the buildings were much higher than the mean concentration value (49.1 Bq/m3) of indoor radon in Poland quoted so far. These results cast a completely new light on the necessity to perform measurements of radon concentration in residential buildings in Poland, no more with reference to small areas with outcrops of crystalline rocks (especially the Sudetes, being the Polish fragment of the European Variscan belt), but for all the major tectonic units within Poland. 相似文献
932.
Modelling the Ecological Vulnerability to Forest Fires in Mediterranean Ecosystems Using Geographic Information Technologies 总被引:1,自引:0,他引:1
Beatriz Duguy José Antonio Alloza M. Jaime Baeza Juan De la Riva Maite Echeverría Paloma Ibarra Juan Llovet Fernando Pérez Cabello Pere Rovira Ramon V. Vallejo 《Environmental management》2012,50(6):1012-1026
Forest fires represent a major driver of change at the ecosystem and landscape levels in the Mediterranean region. Environmental features and vegetation are key factors to estimate the ecological vulnerability to fire; defined as the degree to which an ecosystem is susceptible to, and unable to cope with, adverse effects of fire (provided a fire occurs). Given the predicted climatic changes for the region, it is urgent to validate spatially explicit tools for assessing this vulnerability in order to support the design of new fire prevention and restoration strategies. This work presents an innovative GIS-based modelling approach to evaluate the ecological vulnerability to fire of an ecosystem, considering its main components (soil and vegetation) and different time scales. The evaluation was structured in three stages: short-term (focussed on soil degradation risk), medium-term (focussed on changes in vegetation), and coupling of the short- and medium-term vulnerabilities. The model was implemented in two regions: Aragón (inland North-eastern Spain) and Valencia (eastern Spain). Maps of the ecological vulnerability to fire were produced at a regional scale. We partially validated the model in a study site combining two complementary approaches that focused on testing the adequacy of model’s predictions in three ecosystems, all very common in fire-prone landscapes of eastern Spain: two shrublands and a pine forest. Both approaches were based on the comparison of model’s predictions with values of NDVI (Normalized Difference Vegetation Index), which is considered a good proxy for green biomass. Both methods showed that the model’s performance is satisfactory when applied to the three selected vegetation types. 相似文献
933.
The water-soluble fraction (WSF) of petroleum contains a mixture of polycyclic aromatic hydrocarbons, volatile hydrocarbons, phenols, and heterocyclic compounds, considered deleterious to aquatic biota. Marine “pejerrey” Odontesthes argentinensis (Teleostei: Atherinopsidae) has a great commercial importance in local fisheries and a high potential for aquaculture. The aim of this study was to evaluate the histopathological effects in “pejerrey” larvae exposed to different concentrations of petroleum WSF. The chronic toxicity test was conducted with newly hatched larvae exposed for 21 days to sublethal concentrations of WSF (2.5, 5, 10, and 20 % of WSF), plus one control. Survival and growth were significantly lower in the highest concentration. Several histopathological changes were found in the gills (e.g., hyperplasia, aneurisms, edema, and necrosis), kidney (e.g., nuclear alterations, decrease in the hematopoietic cells), and liver (e.g., hypertrophy, karyorrhexis, and karyopyknosis). An index of branchial lesion was proposed to standardize gill lesions to different pollutants. 相似文献
934.
Sulfate reducing bacteria (SRB) are important mercury methylators in sediments, but information on mercury methylators in other compartments is ambiguous. To investigate SRB involvement in methylation in Amazonian periphyton, the relationship between Hg methylation potential and SRB (Desulfobacteraceae, Desulfobulbaceae and Desulfovibrionaceae) abundance in Eichhornia crassipes and Polygonum densiflorum root associated periphyton was examined. Periphyton subsamples of each macrophyte were amended with electron donors (lactate, acetate and propionate) or inhibitors (molybdate) of sulfate reduction to create differences in SRB subgroup abundance, which was measured by quantitative real-time PCR with primers specific for the 16S rRNA gene. Mercury methylation and demethylation potentials were determined by a stable isotope tracer technique using 200HgCl and CH3202HgCl, respectively. Relative abundance of Desulfobacteraceae (<0.01-12.5%) and Desulfovibrionaceae (0.01-6.8%) were both highly variable among samples and subsamples, but a significant linear relationship (p < 0.05) was found between Desulfobacteraceae abundance and net methylmercury formation among treatments of the same macrophyte periphyton and among all P. densiflorum samples, suggesting that Desulfobacteraceae bacteria are the most important mercury methylators among SRB families. Yet, molybdate only partially inhibited mercury methylation potentials, suggesting the involvement of other microorganisms as well. The response of net methylmercury production to the different electron donors and molybdate was highly variable (3-1104 pg g−1 in 12 h) among samples, as was the net formation in control samples (17-164 pg g−1 in 12 h). This demonstrates the importance of community variability and complexity of microbial interactions for the overall methylmercury production in periphyton and their response to external stimulus. 相似文献
935.
Mamindy-Pajany Y Hamer B Roméo M Géret F Galgani F Durmiši E Hurel C Marmier N 《Chemosphere》2011,82(3):362-369
This work investigates the ecotoxicological evaluation of contaminated dredged sediments from French Mediterranean navy harbour (A), commercial port (B) and two composite specimens (C) and (D) coming from the mixture of A and B with other port sediments. The toxicity of elutriates from these sediments is estimated using embryo-toxicity test, Microtox® solid phase test, LuminoTox, phytotoxicity tests and genotoxicity test. Bioassay responses are not clearly correlated with chemical contamination in the whole sediment and vary as a function of tested organisms. The highest contaminated samples (A and C) are almost always more toxic than the less contaminated samples (B and D). Among composite sediments, the mixture effect with other sediments is not efficient to decrease toxicity in sample C, suggesting that other parameters influence toxicity level such as particle size or organic matter content. These parameters should be taken into consideration in order to improve the efficiency of the mixture process and produce composite sediments with low toxicity. 相似文献
936.
The impairment of root growth and photosynthetical functioning are the main impacts of trace elements on woody plant seedlings. In this work, we assessed the response of Holm oak (Quercusilex subsp. ballota) and mastic shrub (Pistacia lentiscus) seedlings to high concentrations of Cd and Tl in the rhizosphere. These are non-essential trace elements, with a potential high mobility in the soil-plant system. Seedlings of these species are frequently used in the afforestation of degraded soils in mining areas. Plants were exposed to different levels of Cd (20, 80 and 200 mg L−1) and Tl (2, 10 and 20 mg L−1) in a sand culture. Biomass allocation, growth rates, chlorophyll fluorescence and gas exchange were studied. Both metals affected root biomass. Cadmium produced an increase in the root mass ratio and a decrease in the specific leaf area of the plants in oak seedlings, while Tl did not provoke such response. Mastic plants were more sensitive to Tl and Cd than oak plants. Between elements, Tl provoked more severe toxic effects in the plants, affecting the antennae complexes and reaction centers of the photosystem II. Both elements decreased net assimilation rates (down to a 20% of the control plants) and stomatal conductance (5-10% of the values for the control plants). Cadmium was highly retained in the roots of both species, while Tl was highly translocated into the leaves. In general, Holm oak showed a higher tolerance for Cd than for Tl, and a higher resistance to both metals than mastic shrub, due to a high capacity for Cd retention at the root level. However, such accumulation in roots may induce water stress in the seedling exposed to Cd. 相似文献
937.
Wastewater treatment plants receive organic contaminants, such as pesticides, which reach the sewage system from domestic, industrial or agricultural activities. In wastewater, which is a complex mixture of organic and inorganic compounds, biotic or abiotic degradation of contaminants can be affected by the presence of co-solutes. The photodecomposition in natural sunlight of two neonicotinoid insecticides, thiamethoxam and thiacloprid, was investigated in wastewater, aqueous extracts of sewage sludge and in aqueous surfactant solutions, which are abundant in wastewater. Dissipation in the dark was also studied in wastewater, due to reduction of transmitted sunlight in wastewater ponds. With regard to photolysis, thiamethoxam degraded rapidly in all the aqueous solutions. Among them sewage sludge extracts slightly modified (average half-life 17.6 h), wastewater increased (13.7 h) and non-ionic surfactants led, as a family, to the highest dissipation rates (average 6.2 h), with respect to control water (18.7 h). Additionally this pesticide also underwent a slower biodegradation process in wastewater in the dark under anaerobic conditions (around 25 d). A metabolite of thiamethoxam from the biological decomposition in wastewater was identified by HPLC/MS. On the other hand thiacloprid was found to be resistant to photo- and biodecomposition and remained almost unchanged during the experimental periods in all the tested media. 相似文献
938.
Oxidative stress, cytoxicity, and cell mortality induced by nano-sized lead in aqueous suspensions 总被引:2,自引:0,他引:2
Cornejo-Garrido H Kibanova D Nieto-Camacho A Guzmán J Ramírez-Apan T Fernández-Lomelín P Garduño ML Cervini-Silva J 《Chemosphere》2011,84(10):1329-1335
This paper reports on the effect of aqueous and nano-particulated Pb on oxidative stress (lipid peroxidation), cytoxicity, and cell mortality. As determined by the Thiobarbituric Acid Reactive Substances (TBARS) method, only 6 h after incubation aqueous suspensions bearing nano-sized PbO2, soluble Pb(II), and brain-homogenate only suspensions, were determined to contain as much as ca. 7, 5, and 1 nmol TBARS mg protein−1, respectively. Exposure of human cells (central nervous system, prostate, leukemia, colon, breast, lung cells) to nano-PbO2 led to cell-growth inhibition values (%) ca. ≤18.7%. Finally, as estimated by the Artemia salina test, cell mortality values were found to show high-survival larvae rates. Microscopic observations revealed that Pb particles were swallowed, but caused no mortality, however. 相似文献
939.
Estrogens are a class of micro-pollutants found in water at low concentrations (in the ng L−1 range), but often sufficient to exert estrogenic effects due to their high estrogenic potency. Disinfection of waters containing estrogens through oxidative processes has been shown to lead to the formation of disinfection byproducts, which may also be estrogenic. The present work investigates the formation of disinfection byproducts of 17β-estradiol (E2) and estrone (E1) in the treatment of water with ozone. Experiments have been carried out at two different concentrations of the estrogens in ground water (100 ng L−1 and 100 μg L−1) and at varying ozone dosages (0-30 mg L−1). Detection of the estrogens and their disinfection byproducts in the water samples has been performed by means of ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a triple quadrupole (QqQ) and a quadrupole-time of flight (QqTOF) instrument. Both E2 and E1 have been found to form two main byproducts, with molecular mass (MM) 288 and 278 in the case of E2, and 286 and 276 in the case of E1, following presumably the same reaction pathways. The E2 byproduct with MM 288 has been identified as 10epsilon-17beta-dihydroxy-1,4-estradieno-3-one (DEO), in agreement with previously published results. The molecular structures and the formation pathways of the other three newly identified byproducts have been suggested. These byproducts have been found to be formed at both high and low concentrations of the estrogens and to be persistent even after application of high ozone dosages. 相似文献
940.
García-Esquinas E Pérez-Gómez B Fernández MA Pérez-Meixeira AM Gil E de Paz C Iriso A Sanz JC Astray J Cisneros M de Santos A Asensio A García-Sagredo JM García JF Vioque J Pollán M López-Abente G González MJ Martínez M Bohigas PA Pastor R Aragonés N 《Chemosphere》2011,85(2):268-276