Stratigraphic sequence, elemental concentrations and heavy metal pollution in Holocene sediments from the Tinto-Odiel Estuary, southwestern Spain   总被引：1，自引：0，他引：1  

F. Ruiz  M. L. González-Regalado  J. Borrego  J. A. Morales  J. G. Pendón  J. M. Muñoz 《Environmental Geology》1998,34(4):270-278

 The Holocene filling of the Tinto-Odiel Estuary comprises seven lithofacies over a Mio-Pliocene substrate. The sequence includes three system tracts: lowstand system (10 000 to 8700 years BP), transgressive system (8700 to 7000 years BP), and regressive system (7000 to Recent). Twenty sediment samples from the 50-m borehole were analyzed for their major components and minor element concentrations. Two multivariate analysis methods, principal component analysis and cluster analysis, were performed in the analytical data set to help visualize the sample clusters and the element associations. Samples corresponding to unpolluted, pre-mining sediments are clearly separated by cluster analysis, mainly as a result of the low content in sulphide-associated heavy metals such as Cu, Zn, As, Ag, and Pb. So, these sediments may be utilized as a background for geochemical analysis (bulk sample) in other adjacent estuaries, both in sandy and silty-clayey sediments. As a consequence of large-scale mining and smelting operations occurred since prehistoric times on the river banks, a rapid rise in the metal pollution was found in the upper 2.5 m of the natural filling, with values exceeding up to ten times the natural background levels. In addition, since the mid-1960s, large amounts of waste and pollutant effluents have been discharged from industries located around the estuary, increasing the heavy metal content in the last 0.3 m of the natural sedimentation. Received: 18 August 1997 · Accepted: 19 January 1998  相似文献   

The evolution of the V−K colours of single stellar populations     

Léo Girardi  & Gianpaolo Bertelli 《Monthly notices of the Royal Astronomical Society》1998,300(2):533-549

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Long slit spectroscopy of the nuclear zone of NGC 253     

C. Muñoz-Tuñon  J. M. Vilchez  H. O. Castañeda 《Astrophysics and Space Science》1990,170(1-2):315-317

We have undertaken a study of the physical conditions of the lonized gas within the starburst region of the galaxy NGC 253, using long slit spectroscopy at high spatial and spectral resolution. Our aim was to identify the appropriate parameters describing the dynamics of the gas and the excitation conditions, in relation with the starburst process. Non-gaussian line profiles and line spliting are clearly observed, indicating a complicated dynamical structure; furthermore, the zones presenting non-circular motions and localized outflow of gas have been spatially sampled at the seeing limit.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Night-time seeing and atmospheric behaviour in the Canary Islands Observatories     

C. Muñoz-Tuñon  F. J. Fuentes 《Astrophysics and Space Science》1990,171(1-2):257-266

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Radial oscillations of warm cores in neutron stars     

J. M. Marti  J. A. Miralles  J. Ma Ibáñez 《Astrophysics and Space Science》1987,139(1):93-101

We have solved the relativistic equations for the radial oscillations of warm cores in neutron stars by assuming a given law for the interior distribution of temperature-the resulting from the condition of relativistic thermal equilibrium-and focussed on the properties of the fundamental modes.Our results let us to establish well-defined regions of stability in a diagram central temperature versus central density.  相似文献   

Correction to: Observational Investigation of the Statistical Properties of Surface-Layer Turbulence in a Suburban Area of São Paulo,Brazil: Objective Analysis of Scaling-Parameter Accuracy and Uncertainties     

da Silveira  Lucas Cardoso  de Oliveira  Amauri Pereira  Sánchez  Maciel Piñero  Codato  Georgia  Ferreira  Maurício Jonas  Filho  Edson Pereira Marques  Božnar  Marija Zlata  Mlakar  Primož 《Boundary-Layer Meteorology》2022,185(2):197-197

Boundary-Layer Meteorology -  相似文献   

Influence of water temperature and salinity on seasonal occurrences of Vibrio cholerae and enteric bacteria in oyster-producing areas of Veracruz, México     

Castañeda Chávez Mdel R  Pardio Sedas V  Orrantia Borunda E  Lango Reynoso F 《Marine pollution bulletin》2005,50(12):1641-1648

The influence of temperature and salinity on the occurrence of Vibrio cholerae, Escherichia coli and Salmonella spp. associated with water and oyster samples was investigated in two lagoons on the Atlantic Coast of Veracruz, Mexico over a 1-year period. The results indicated that seasonal salinity variability and warm temperatures, as well as nutrient influx, may influence the occurrence of V. cholera. non-O1 and O1. The conditions found in the Alvarado (31.12 °C, 6.27‰, pH = 8.74) and La Mancha lagoons (31.38 °C, 24.18‰, pH = 9.15) during the rainy season 2002 favored the occurrence of V. cholera O1 Inaba enterotoxin positive traced in oysters. Vibrio alginolyticus was detected in Alvarado lagoon water samples during the winter season. E. coli and Salmonella spp. were isolated from water samples from the La Mancha (90–96.7% and 86.7–96.7%) and Alvarado (88.6–97.1% and 88.6–100%) lagoons. Occurrence of bacteria may be due to effluents from urban, agricultural and industrial areas.  相似文献   

A comparative study of barium peculiarity indices     

M. Rego  M. Cornide  J. L. Fernández-Villacañas 《Astrophysics and Space Science》1986,123(2):313-324

From DDO photometry an indicator of barium stars have been elaborated. This indicator is closely related to the barium line intensities derived by means of narrow-band photometry and spectroscopic observations. A better discrimination appears when our indicator is used instead of the qualitative Warner index.  相似文献   

A methodology to classify extreme rainfall events in the western mediterranean area     

M. C. Casas  B. Codina  A. Redaño  J. Lorente 《Theoretical and Applied Climatology》2004,77(3-4):139-150

Summary From a large data set (1927–1992) of rainfall rate in Barcelona, the relationship between maximum rainfall rates for time intervals between 5 minutes and 24 hours has been investigated. Intensity-Duration-Frequency (IDF) curves and their master equation for every return period in Barcelona have been obtained. A cluster analysis has yielded four main classes of extreme rainfall events in this area, corresponding to durations shorter than 35 minutes, 1 hour, 2–6 hours and those longer than 6 hours respectively. An index to classify extreme rainfall events has been proposed. This index gives some information about the severity of storms taking into account the contribution of different scales implied in rainfall processes.  相似文献   

Effects of the intertidal burrowing crab<Emphasis Type="Italic">Chasmagnathus granulatus</Emphasis> on infaunal zonation patterns,tidal behavior,and risk of mortality     

Mauricio?EscapaEmail author  Oscar?Iribarne  Diego?Navarro 《Estuaries and Coasts》2004,27(1):120-131

Rhythmic movements in response to tidal cycles are characteristic of infaunal inhabitant of intertidal soft-bottoms, allowing them to remain in the area with best living conditions. The effect of bioturbators as modifier of local environmental conditions and thus of gradients in intertidal habitats, has not been investigated yet. The Atlantic estuarine intertidal areas are dominated by the burrowing crabChasmagnathus granulatus that generates strong environmental heterogeneity by affecting the physical-chemical characteristics of the sediment. The comparison between intertidal areas with and without crab shows that sediments in the crab beds remain more humid, softer, and homogeneous across the intertidal and along the tidal cycle than areas without crabs. The densities of infauna were higher at high intertidal zones in crab beds than in similar areas without crabs. Infaunal organisms performed vertical movements into the sediment following the tidal cycle that were always of higher magnitude in habitats without crabs. Infaunal species tend to spend most of the time buried into the sediment in the crab bed. Migratory shorebirds use the Atlantic estuarine environments as stopover or wintering sites. They feed (mainly on polychaetes) in the low intertidal zones of both habitats (with and without crabs), but they also feed in the upper intertidal of the crab bed; polychaete per capita mortality rate is higher in the upper part of the crab bed. Environmental heterogeneity produced by crab disturbance has an effect on the infaunal behavior, risk of mortality, and the zonation pattern. This is another example of the ecosystem engineering ability of a burrowing intertidal species.  相似文献