排序方式: 共有42条查询结果,搜索用时 0 毫秒
21.
Temporal variations of polycyclic aromatic hydrocarbon (PAH) concentrations in leaves of a Mediterranean evergreen oak, Quercus ilex L., were investigated in order to assess the suitability of this species to biomonitor PAH air contamination. Leaf samples were collected at six sites of the urban area of Naples (Italy) and at a control site in the Vesuvius National Park, in May and September 2001, and in January and May 2002. PAH extraction was conducted by sonication in dichloromethane-acetone and quantification by GC-MS. In winter, leaf total PAH concentrations showed, at all the urban sites, values 2-fold higher than in all the other samplings, reflecting the temporal trend reported for PAH air contamination in the Naples urban area. Moreover, leaf PAH concentrations showed, at all the urban sites, a decrease in May 2002 after the winter accumulation. At the control site leaf PAH concentrations showed lower values and smaller temporal variations than at the urban sites. The findings support the suitability of Q. ilex leaves to monitor temporal variations in PAH contamination. The highest winter concentrations of total PAHs were due to the medium molecular weight PAHs that increased with respect to both low and high molecular weight PAHs. The medium molecular weight PAHs showed the same temporal trend both at the urban and remote sites. 相似文献
22.
Assessment of the effects of Cr, Cu, Ni and Pb soil contamination by ecotoxicological tests 总被引:1,自引:0,他引:1
Maisto G Manzo S De Nicola F Carotenuto R Rocco A Alfani A 《Journal of environmental monitoring : JEM》2011,13(11):3049-3056
This study aimed to assess soil quality by chemical and ecotoxicological investigations and to check the correspondence between soil metal concentrations and ecotoxicity. For these purposes, surface soils collected at four adjacent roadside urban parks and at a former industrial area were characterized for C/N, organic matter content, texture, and pH. Cr, Cu, Ni and Pb, chosen among the most representative soil metal contaminants, were measured as total content and as available and water soluble fractions. In addition, the total concentrations of the investigated metals were used to calculate two chemical indices: the contamination and the potential ecological risk factors. The toxicity of the investigated soils was evaluated by an ecotoxicity test battery carried out on both soil samples (Vibrio fischeri, Heterocypris incongruens and Sinapis alba) and elutriates (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum). The findings, both by the chemical and ecotoxicological approaches, would suggest that the soils with high metal contamination pose ecological risks. On the other hand, moderately metal contaminated soils did not exclude soil ecotoxicity. In fact, toxic effects were also highlighted in soils with low metal content, toxicity being affected by metal availability and soil characteristics. Moreover, the results suggest the importance of using a battery of tests to assess soil ecotoxicity. 相似文献
23.
Stephen G. Perz Jeffrey Hoelle Karla Rocha Veronica Passos Flavia Leite Julia Cortes 《Journal of Land Use Science》2017,12(4):231-251
In the complex causation behind land change, dependent causation can play a central role. A case in point concerns land tenure diversity, where contrasting use rules for different lands may affect the impacts of other drivers on land use outcomes. We therefore evaluate the evolutionary theory of land rights (ETLR), which assumes homogeneous private property rights, in order to test for dependent causation due to distinct use rules among various types of private lands. In the present analysis, we focus on whether land tenure type modifies the effects of highway infrastructure on key outcomes highlighted in the ETLR framework. We take up the case of rural settlements along the Inter-Oceanic Highway in the eastern part of the Brazilian state of Acre, where there is considerable land tenure diversity. Findings from multivariate models for land titling, the castanha nut harvest, and cattle pasture all indicate that the effects of infrastructure depend on land tenure type. These results confirm the importance of dependent causation behind land use and bear implications for theory on land change, infrastructure impacts, and land system science. 相似文献
24.
J. Gasperi C. Sebastian V. Ruban M. Delamain S. Percot L. Wiest C. Mirande E. Caupos D. Demare M. Diallo Kessoo M. Saad J. J. Schwartz P. Dubois C. Fratta H. Wolff R. Moilleron G. Chebbo C. Cren M. Millet S. Barraud M. C. Gromaire 《Environmental science and pollution research international》2014,21(8):5282-5283
25.
Brassica juncea cv. 426308 was grown in soils containing 150 mg Cd(2+)kg(-1) soil. After 38 days, the soil was amended with two rates of citric acid or NTA (10 and 20 mmol kg(-1) soil). Control soil was not amended with chelates. Plants were harvested during growth, immediately before and seven days after chelate addition. Shoot composition of organic and phenolic acids and shoot Cd(2+) concentration were determined. Cadmium concentration remained constant during the growth and increased following NTA and citric acid amendments depending on chelate type and concentration. The highest increments in Cd(2+) were measured after the addition of NTA. Compared to the control, 10 and 20 NTA-treated plants showed two- and three-fold increases, respectively. At 150 mg Cd(2+)kg(-1) soil the amount of organic and phenolic acids in the leaves of B. juncea was always higher than that detected in the control. A direct correlation between organic acid concentration and cadmium content was detected both during growth and after chelate addition. On the contrary, the amount of phenols seemed to be correlated with the metal content only in non-amended and NTA-treated plants. The 10 and 20 citric acid additions caused 45% and 90% increases in shoot phenolic acids although cadmium content rose to a smaller extent. The inhibition of citrate synthase and the entrance of phosphoenolpyruvate in shikimate pathway leading to the formation of aromatic compounds might come into play. The increase in phenylalanine ammonialyase activity following citric acid amendments suggested this metabolic response. 相似文献
26.
Modern agriculture is dependent on phosphate rock (PR), which is a nonrenewable resource. Improvement of phosphorus (P) availability for crops in agricultural soils represents a key strategy to slow down the depletion of PR. The aim of this study was to identify potential P biofertilisers among saprotrophic fungal species. We tested 30 fungal strains belonging to 28 taxa (4 Zygomycota and 24 Ascomycota) and with different life strategies. The study showed that many saprotrophic fungi have the ability to mobilise P from insoluble forms according to a variety of mechanisms. Our results expand the pool of P solubilising fungal species, also suggesting a new solubilisation index and shedding light on parameters that could be basic in the selection of efficient soil P-biofertilisers fungi. Rhizopus stolonifer var. stolonifer, Aspergillus niger and Alternaria alternata were found to be the best performing strains in terms of amounts of TCP solubilisation. 相似文献
27.
Meritxell Aulinas Maite Garcia-Valles Domingo Gimeno Jose Luis Fernandez-Turiel Flavia Ruggieri Montserrat Pugès 《Environmental science and pollution research international》2009,16(4):443-452
Background, aim, and scope The first step in the restoration of a medieval stained glass window is the evaluation of its degree of degradation. This
implies the study of the chemical composition of the stained glass as well as the new mineral phases developed on its surface
(patinas). Patinas are clearly related to glass composition, time, environmental conditions, microenvironments developed in
local zones, bioactivity, physical and chemical factors, etc. This study was carried out on patinas developed in selected
Na-rich stained glass of the Santa Maria de Pedralbes Monastery (Barcelona, Spain). The location of this monument in the city
(about 5 km from the shoreline and close to the Collserola hill flank) helped to determine the environmental conditions in
which patinas developed. The aim of our study was to characterize the patinas formed on the surface of the selected glass
of this monastery in order to understand the role of the chemical composition of the original glass (Na-rich) as well as the
environmental conditions in which they developed.
Materials and methods Powdered samples of two different color-type patinas (ochre-orange and brownish) were collected in the external and internal
parts of the stained glass windows of the Prebystery and Chapter House of the Pedralbes Monastery by using a precision (odontological)
drill. These patinas were subsequently analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).
Results XRD analyses evidenced the presence of sulfates (gypsum and thenardite), calcite, Ca-oxalates (whewellite and weddellite),
and quartz forming part of the patinas. Although these mineral phases can be found in both color-type patinas, whewellite
and thenardite are more common in the ochre-orange patinas. The results obtained were validated by the FTIR measurements.
It has been observed, when thenardite is present, that gypsum occurs as traces. Thenardite is in most of the cases associated
with whewellite and mainly occurs in the internal parts of the glass. In contrast, weddellite is limited to the absence of
thenardite and whewellite and to the external parts of the stained glass. Quartz is present in all the patinas independent
of their location and color. Calcite also occurs in many samples. It appears in both color-type patinas and, in some cases,
is associated to the presence of weddellite but not to whewellite and/or thenardite.
Discussion Glass composition together with environmental conditions and location of the patinas (internal or external parts of the stained
glass window), as well as the provenance of the glass within the monastery, are the main factors that define the development
of the new mineral phases. Moreover, the action of microorganisms, when present, can also strongly influence the development
of some mineral phases. For example, the formation of calcite in the external parts of the stained glass (associated with
the presence of oxalates) is related to the action of microorganisms. When calcite is formed in the internal parts of the
glass and it is not associated with the presence of Ca-oxalates, an inorganic origin can be invoked. The presence of weddellite
requires a very humid microenvironment with very little exposure to sunlight. In fact, this mineral phase has only been observed
in the external parts of some glass located in the humid and shady side of the monastery. Whewellite (which only appears in
the internal parts) needs a low degree of relative humidity. It has been observed that sulfur precipitating in basically one
mineral phase (thenardite or gypsum) depends on the microenvironmental conditions of the moment and the glass composition.
When thenardite occurs, it can be maintained that the original glass is of Na composition. The occurrence of quartz in all
samples is interpreted as being due to the deposition of atmospheric particulate matter. The color of the patinas can be originated
by different processes (presence of carotenes, organic pigmentation, atmospheric contamination, etc.).
Conclusions In the case of moderately weathered stained glass windows, the combination of XRD and FTIR techniques is very useful to obtain
a fast preliminary evaluation of the degree of weathering of a stained glass window. The presence of specific mineral phases
in the patina (e.g., thenardite) confirms the Na composition of the original stained glass. This is important since Na-rich
glass underwent a lesser degree of weathering than K- or K-Ca-rich glass. However, their absence cannot preclude other possibilities.
It has been extensively evidenced through time that environmental conditions play an important role on the formation of the
different mineral phases which form part of the patinas.
Recommendations and perspectives The first step in the restoration of a stained glass window is the evaluation of the degree of deterioration of the glass.
This evaluation includes a chemical analysis of the glass as well as a characterization of the patinas developed on their
surfaces. The obtained results will be essential in order to define the best restoration practices to be followed. 相似文献
28.
Stranger M Potgieter-Vermaak S Sacco P Quaglio F Pagani D Cocheo C Godoi AF Van Grieken R 《Environmental monitoring and assessment》2009,149(1-4):411-417
A diffusive sampling method for the determination of gaseous acetic and formic acids, using a radial symmetry diffusive sampler, has been optimised for a 7-day exposure time in this study. Sampling rate determinations were performed on data obtained from a dynamic exposure chamber, simulating the indoor conditions of an empty, closed, room, at room temperature and minimal wind speed. Analysis has been performed by means of ion chromatography. The sampling rates for formic acid concentrations of 128 microg m(-3) and 1248 microg m(-3) were determined to be 91.2 +/- 3.9 ml min(-1) and 111.6 +/- 2.8 ml min(-1), respectively. The acetic acid sampling rate was independent of the concentration in the range 160 microg m(-3)-1564 microg m(-3), and amounted to 97.3 +/- 3.1 ml min(-1). Experimentally determined sampling rates showed deviations of 3% for acetic acid, and 3-21% for formic acid, in relation to theoretically derived values. The blank values were as low as 1.69 +/- 0.07 microg for formic acid and 1.21 +/- 0.14 microg for acetic acid, and detection limits lower than 0.5 microg m(-3) could be achieved, which is an improvement of 98-99% compared to previously validated diffusive sampling methods. This study describes the first step of an extended validation program in which the applicability of these types of samplers for the measurement of organic acids will be validated and optimised for the environmental conditions typical for museum showcases. 相似文献
29.
Cerumen, or propolis, is a mixture of plant resins enriched with bee secretions. In Australia, stingless bees are important
pollinators that use cerumen for nest construction and possibly for colony’s health. While extensive research attests to the
therapeutic properties of honeybee (Apis mellifera) propolis, the biological and medicinal properties of Australian stingless bee cerumen are largely unknown. In this study,
the chemical and biological properties of polar extracts of cerumen from Tetragonula carbonaria in South East Queensland, Australia were investigated using gas chromatography-mass spectrometry (GC-MS) analyses and in
vitro 5-lipoxygenase (5-LOX) cell-free assays. Extracts were tested against comparative (commercial tincture of A. mellifera propolis) and positive controls (Trolox and gallic acid). Distinct GC-MS fingerprints of a mixed diterpenic profile typical
of native bee cerumen were obtained with pimaric acid (6.31 ± 0.97%, w/w), isopimaric acid (12.23 ± 3.03%, w/w), and gallic
acid (5.79 ± 0.81%, w/w) tentatively identified as useful chemical markers. Characteristic flavonoids and prenylated phenolics
found in honeybee propolis were absent. Cerumen extracts from T. carbonaria inhibited activity of 5-LOX, an enzyme known to catalyse production of proinflammatory mediators (IC50 19.97 ± 2.67 μg/ml, mean ± SEM, n = 4). Extracts had similar potency to Trolox (IC50 12.78 ± 1.82 μg/ml), but were less potent than honeybee propolis (IC50 5.90 ± 0.62 μg/ml) or gallic acid (IC50 5.62 ± 0.35 μg/ml, P < 0.001). These findings warrant further investigation of the ecological and medicinal properties of this stingless bee cerumen,
which may herald a commercial potential for the Australian beekeeping industry. 相似文献
30.
Isolation and characterization of a Pseudomonas aeruginosa from a virgin Brazilian Amazon region with potential to degrade atrazine 总被引:1,自引:0,他引:1
Ana Flavia Tonelli Fernandes Michelle Barbosa Partata da Silva Vinicius Vicente Martins Carlos Eduardo Saraiva Miranda Eliana Guedes Stehling 《Environmental science and pollution research international》2014,21(24):13974-13978
The use of pesticides to increase agricultural production can result in the contamination of the environment, causing changes in the genetic structure of organisms and in the loss of biodiversity. This practice is also inducing changes in the rainforest ecosystem. In this work, a Pseudomonas aeruginosa isolated from a preservation soil area of the Brazilian Amazon Forest, without usage of any pesticide, was evaluated for its potential to degrade atrazine. This isolate presented all responsible genes (atzA, atzB, atzC, atzD, atzE, and atzF) for atrazine mineralization and demonstrated capacity to use atrazine as a nitrogen source, having achieved a reduction of 44 % of the initial concentration of atrazine after 24 h. These results confirm gene dispersion and/or a possible contamination of the area with the herbicide, which reinforces global concern of the increase and intensive use of pesticides worldwide. 相似文献