Lead isotopes as tracers of anthropogenic pollution in urban topsoils of Mexico City   总被引：1，自引：0，他引：1  

Ofelia Morton-Bermea  María Teresa Rodríguez-Salazar  Elizabeth Hernández-Alvarez  Ma Elena García-Arreola  Rufino Lozano-Santacruz 《Chemie der Erde / Geochemistry》2011,(2):189-195

A survey was performed to trace the main source of anthropogenic Pb pollution in Mexico City through Pb isotopic signatures (²⁰⁸Pb/²⁰⁴Pb, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁶Pb/²⁰⁷Pb, and ²⁰⁸Pb/²⁰⁷Pb) from 103 urban topsoil (0–5 cm) samples. Those were collected in the metropolitan area of Mexico City and compared with isotopic compositions of leaded gasoline (LG), domestic Pb ores (DLO) and parent rock (PR). The isotope ratios (IRs) of Pb were determined by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) and total Pb concentration analyzed by wavelength dispersive X-ray fluorescence (WDXRF). The range of Pb concentrations levels in urban topsoil samples was 15–473 mg/kg. The IR values obtained for these samples were 37.965–39.718 (²⁰⁸Pb/²⁰⁴Pb), 18.375–19.204 (²⁰⁶Pb/²⁰⁴Pb), 1.177–1.218 (²⁰⁶Pb/²⁰⁷Pb) and 2.443–2.496 (²⁰⁸Pb/²⁰⁷Pb). Analyzed topsoil samples with low Pb content (<50 mg/kg) displayed high dispersion in ²⁰⁸Pb/²⁰⁴Pb values, which are determined by different natural sources. Samples with 51–200 mg/kg Pb content, shown low dispersion that revealed the mixing between the natural Pb and anthropogenic Pb. The assessment of the IR values shown that, as Pb concentration increases, a trend toward gasoline IR data has been observed. The results obtained by this research suggest that although the use of leaded petrol had been banned in Mexico since 1997, the Pb pollution in the urban topsoils due to the historical use of Pb in petrol is still significant.  相似文献   

Estimating global discards and their potential reduction for the Galician fishing fleet (NW Spain)     

Ian Vázquez-Rowe  M Teresa MoreiraGumersindo Feijoo 《Marine Policy》2011

This study presents the first comprehensive estimation of discard amounts in the Galician fishing fleet, in order to provide an integral view of this increasing environmental problem at a regional scale. Subsequently, a series of improvement actions relating to discard minimization are suggested with the goal of enhancing the performance of the Galician fishing fleet through discard minimization. Discard estimates were constructed individually for the different Galician fisheries by aggregating primary data obtained from a total of 89 fishing vessels and secondary data for those fleets that were not directly sampled. Results showed that roughly 60,250 t of marine organisms were discarded by the Galician fleet in 2008, representing 16.9% of the total capture. Moreover, an important percentage of these discards were linked mainly to trawling vessels and to a lesser extent, to certain long lining fisheries. Therefore, improved management measures in target stocks should take into account the fact that alternative fishing gears other than trawl nets may reduce the amount of discards for certain species. This estimation may improve the assessment of stocks and help to quantify the damage that discards may have on wild ecosystems.  相似文献   

Role of different salt marsh plants on metal retention in an urban estuary (Lima estuary,NW Portugal)     

C.M.R. Almeida  Ana P. Mucha  M. Teresa Vasconcelos 《Estuarine, Coastal and Shelf Science》2011

The aim of the present work was to understand the role different salt marsh plants on metal distribution and retention in the Lima River estuary (NW Portugal), which to our knowledge have not been ascertained in this area yet. The knowledge of these differences is an important requirement for the development of appropriate management strategies, and is poorly described for Eurosiberian estuaries, like the one selected. In addition it is important to understand the difference among introduced and native salt marsh plants. In this work, metal levels (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were surveyed (by atomic absorption spectrometry) in sediments from sites vegetated with Juncus maritimus, Spartina patens, Phragmites australis and Triglochin striata (rhizo-sediments), in non-vegetated sediments and in the different tissues of the plants (roots, rhizomes and aerial shoots). In general, rhizo-sediments had higher metal concentrations than non-vegetated sediments, a feature that seems common to sediments colonized by salt marsh plants of different estuarine areas. All plants concentrated metals, at least Cd, Cu and Zn (and Pb for T. striata) in their belowground structures ([M]_{belowground tissues}/[M]_{non-vegetated sediment} > 1). However, when considered per unit of salt marsh area, the different selected plants played a different role on sediment metal distribution and retention. Triglochin striata retained a significant metal burden in it belowground structures (root plus rhizomes) acting like a possible phyto-stabilizer, whereas P. australis had an higher metal burden in aboveground tissues acting as a possible phyto-extractor. As for J. maritimus and S. patens, metal burden distribution between above and belowground structures depended on the metal, with J. maritimus retaining, for instance, much more Cd and Cu in the aboveground than in the belowground structures. Therefore, the presence of invasive and exotic plants in some areas of the salt marsh may considerably affect metal distribution and retention in the estuarine region.  相似文献   

Middle and late Holocene climate change and human impact inferred from diatoms,algae and aquatic macrophyte pollen in sediments from Lake Montcortès (NE Iberian Peninsula)     

Paolo Scussolini  Teresa Vegas-Vilarrúbia  Valentí Rull  Juan Pablo Corella  Blas Valero-Garcés  Joan Gomà 《Journal of Paleolimnology》2011,46(3):369-385

During the middle and late Holocene, the Iberian Peninsula underwent large climatic and hydrologic changes, but the temporal resolution and regional distribution of available palaeoenvironmental records is still insufficient for a comprehensive assessment of the regional variability. The high sedimentation rate in karstic, meromictic Montcortès Lake (Catalan pre-Pyrenees) allows for a detailed reconstruction of the regional palaeoecology over the last 5,340 years using diatom analysis, aquatic pollen, sedimentological data, and historic documentary records. Results show marked fluctuations in diatom species assemblage composition, mainly between dominant Cyclotella taxa and small Fragilariales. We suggest that the conspicuous alternation between Cyclotella comta and C. cyclopuncta reflects changes in trophic state, while the succession of centric and pennate species most likely reflects changes in the hydrology of the lake. The diatom assemblages were used to identify six main phases: (1) high productivity and likely lower lake levels before 2350 BC, (2) lower lake levels and a strong arid phase between 2350 and 1850 BC, (3) lake level increase between 1850 and 850 BC, (4) relatively high lake level with fluctuating conditions during the Iberian and Roman Epochs (650 BC–350 AD), (5) lower lake levels, unfavourable conditions for diatom preservation, eutrophication and erosion triggered by increased human activities in the watershed during the Medieval Climate Anomaly (900–1300 AD), and (6) relatively higher lake levels during the LIA (1380–1850 AD) and afterwards. The combined study of diatoms, algae and pollen provides a detailed reconstruction of past climate, which refines understanding of regional environmental variability and interactions between climate and socio-economic conditions in the Pyrenees.  相似文献   

The assessment of environmental pollution caused by mining and metallurgy wastes from highly polluted post-industrial regions in Southern Poland     

Joanna Paldyna  Beata Krasnodebska-Ostrega  Karolina Kregielewska  Joanna Kowalska  Lukasz Jedynak  Jerzy Golimowski  Tomasz Grobelski  Jadwiga Farbiszewska-Kiczma  Teresa Farbiszewska 《Environmental Earth Sciences》2013,68(2):439-450

Stored metallurgy and mining wastes contain relatively high amounts of potentially toxic elements. To monitor the distribution of contaminants originating from dumps, the chemical and physical properties of the wastes must be characterised. In this study, the chemical properties of wastes deposited in two different locations in Southern Poland (Szklary and Zloty Stok) were evaluated. Heaps located in Zloty Stok contain wastes from gold mineralisation comprising arsenic while wastes in Szklary originate from a factory that produced an iron-nickel alloy. In Szklary the total concentrations of Ca, Mg, Fe, Zn, Mn, Cr, Co, Cu, Ni, Tl, Ag, Cd and Pb were determined, while in Zloty Stok also As is an important contaminant. To assess the risk of contamination of the surrounding environment and to select the proper method for removing the contaminants, information on the distribution of elements between operationally defined phases must be obtained. For this purpose, a six-step sequential extraction was used. The mobility of most elements in the wastes from Szklary and Zloty Stok was relatively low; however, the large amount of As, 40–180 mg L^?1, that could be released to environment in case of Zloty Stok was high. The results of fractionation studies indicated that Ag, Cd, Tl, Co, Cu, Cr, Pb, Zn and Mn may be released into environment under low pH and low redox potential conditions, which can be induced by bacterial activity.  相似文献   

Multi-stage Ag–Bi–Co–Ni–U and Cu–Bi vein mineralization at Wittichen,Schwarzwald, SW Germany: geological setting,ore mineralogy,and fluid evolution     

Sebastian?Staude  Wolfgang?Werner  Teresa?Mordhorst  Klaus?Wemmer  Dorrit?E.?Jacob  Gregor?MarklEmail author 《Mineralium Deposita》2012,47(3):251-276

The Wittichen Co–Ag–Bi–U mining area (Schwarzwald ore district, SW Germany) hosts several unconformity-related vein-type mineralizations within Variscan leucogranite and Permian to Triassic redbeds. The multistage mineralization formed at the intersection of two fault systems in the last 250 Ma. A Permo-Triassic ore stage I with minor U–Bi–quartz–fluorite mineralization is followed by a Jurassic to Cretaceous ore stage II with the main Ag and Co mineralization consisting of several generations of gangue minerals that host the sub-stages of U–Bi, Bi–Ag, Ni–As–Bi and Co–As–Bi. Important ore minerals are native elements, Co and Ni arsenides, and pitchblende; sulphides are absent. The Miocene ore stage III comprises barite with the Cu–Bi sulfosalts emplectite, wittichenite and aikinite, and the sulphides anilite and djurleite besides native Bi, chalcopyrite, sphalerite, galena and tennantite. The mineral-forming fluid system changed from low salinity (<5 wt.% NaCl) at high temperature (around 300°C) in Permian to highly saline (around 25 wt.% NaCl + CaCl₂) at lower temperatures (50–150°C) in Triassic to Cretaceous times. Thermodynamic calculations and comparison with similar mineralizations worldwide show that the Mesozoic ore-forming fluid was alkaline with redox conditions above the hematite–magnetite buffer. We suggest that the precipitation mechanism for native elements, pitchblende and arsenides is a decrease in pH during fluid mixing processes. REE patterns in fluorite and the occurrence of Bi in all stages suggest a granitic source of some ore-forming elements, whereas, e.g. Ag, Co and Ni probably have been leached from the redbeds. The greater importance of Cu and isotope data indicates that the Miocene ore stage III is more influenced by fluids from the overlying redbeds and limestones than the earlier mineralization stages.  相似文献   

Can a Simulated Flood Experience Improve Social Resilience to Disasters?     

Maria Teresa Carone  Loris Melchiorri  Francesco Romagnoli  Fausto Marincioni 《The Professional geographer》2013,65(4):604-615

The increase of extreme meteorological phenomena, along with continuous population growth, has led to a rising number of flooding disasters. Therefore, there is an urgent need to develop better risk reduction strategies, among which is increased social resilience. Experiencing a disaster is recognized as a factor that positively influences overall community resilience, with particular effects on social resilience; it appears to be more influential than school education. It also has many negative effects, though. Previous studies underline that citizens do not distinguish between different types of experiences. Thus, we investigated whether a simulated experience of a flood can improve social resilience, without being hampered by negative repercussions. The study was executed in five municipalities in three Italian regions involved in the European project LIFE PRIMES, which planned simulation activities for each studied area. Data, collected through the administration of anonymous questionnaires before and after a flood drill, were processed by applying a multicriteria decision analysis tool (PROMETHEE). Results show that the drill significantly augmented perceived social resilience in the smaller studied communities but not in the larger ones, a fact that should be further investigated. Key Words: multicriteria decision analysis, simulated flood experience, social resilience to disasters.  相似文献   

Removal of Carbamazepine,Naproxen, and Trimethoprim from Water by Amberlite XAD‐7: A Kinetic Study     

Joaquín R. Domínguez‐Vargas  Teresa Gonzalez  Patricia Palo  Eduardo M. Cuerda‐Correa 《洁净——土壤、空气、水》2013,41(11):1052-1061

The adsorption kinetics of carbamazepine, naproxen, and trimethoprim in aqueous solution by Amberlite? XAD‐7 has been studied. The influence of adsorbent dose (1–3 g/L), stirring rate (80–240 rpm), pH (2–9), temperature (20–60°C), and initial concentration (25–75 ppm) on the adsorption kinetics has been analyzed. The removal efficiency in the first 2 h reaches 85% for carbamazepine, 60% for naproxen, and 70% for trimethoprim. pH appears to be the most important factor conditioning the removal of these latter solutes, whereas carbamazepine adsorption seems to be independent of the pH of the adsorptive solution. Initial concentration and operation temperature moderately influence the adsorption process. Finally, stirring rate scarcely affects the process. The experimental data have been fitted to four kinetic models, namely pseudo‐first and pseudo‐second order, intra‐particle diffusion and Bangham's. The model providing the best fit is the pseudo‐second order one. Again, pH is the factor that affects the adsorption rate in a more remarkable manner although other parameters such as temperature and stirring rate also contribute to accelerate the removal of the solutes. Under the optimal operation conditions, Amberlite? XAD‐7 exhibits a promising ability for the removal of the pharmaceuticals under study.  相似文献   

Copper Biosorption by Spent Coffee Ground: Equilibrium,Kinetics, and Mechanism     

Nancy Elizabeth Dávila‐Guzmán  Felipe de Jesús Cerino‐Córdova  Eduardo Soto‐Regalado  Jose Rene Rangel‐Mendez  Paola Elizabeth Díaz‐Flores  Maria Teresa Garza‐Gonzalez  José Angel Loredo‐Medrano 《洁净——土壤、空气、水》2013,41(6):557-564

The potential use of spent coffee ground (SCG) for the removal of copper has been investigated as a low‐cost adsorbent for the biosorption of heavy metals. Adsorption batch experiments were conducted to determine isotherms and kinetics. The biosorption equilibrium data were found to fit well the Freundlich model and an experimental maximum biosorption capacity of copper ions 0.214 mmol/g was achieved. The biosorption kinetics of SCG was studied at different adsorbate concentrations (0.1–1.0 mM) and stirring speeds (100–400/min). The results showed an increase in the copper ion uptake with raising the initial metal concentration and the kinetic data followed the pseudo‐second order rate expression. The effect of stirring speed was a significant factor for the external mass transfer resistance at 100/min and coefficients were estimated by the Mathews and Weber model. Biosorption of copper ions onto SCG was observed to be related mainly with the release of calcium and hydrogen ions suggesting that biosorption performance by SCG can be attributed to ion‐exchange mechanism with calcium and hydrogen ions neutralizing the carboxyl and hydroxyl groups of the biomass.  相似文献   

Land change modelling: moving beyond projections     

Martin Paegelow  María Teresa Camacho Olmedo  Jean-François Mas  Thomas Houet  Robert Gilmore Pontius Jr. 《International journal of geographical information science》2013,27(9):1691-1695

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