Cu(II) adsorption from aqueous solution using red mud activated by chemical and thermal treatment     

Fabiano T. da Conceição  Beatriz C. Pichinelli  Mariana S. G. Silva  Rodrigo Braga Moruzzi  Amauri Antonio Menegário  Maria Lucia Pereira Antunes 《Environmental Earth Sciences》2016,75(5):362

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Capability of Paraguaçu estuary (Todos os Santos Bay,Brazil) to form oil–SPM aggregates (OSA) and their ecotoxicological effects on pelagic and benthic organisms     

Mariana C. Rios  Ícaro T.A. Moreira  Olívia M.C. Oliveira  Taís S. Pereira  Marcos de Almeida  Maria Clara L.F. Trindade  Leonardo Menezes  Alex. S. Caldas 《Marine pollution bulletin》2017,114(1):364-371

For experiments concerning the formation of oil–suspended particulate matter (SPM) aggregates (OSA), oil and sediment samples were collected from Campos Basin and six stations of Paraguaçu estuary, Todos os Santos Bay, Brazil, respectively. The sediments samples were analyzed for organic matter determined by the EMBRAPA method, nitrogen determined by the Kjeldahl method, and phosphorus determined by the method described by Aspila. The oil trapped in OSA was extracted following the method described by Moreira. The experiment showed a relationship between the amount of organic matter and OSA formation and consequently the dispersion of the studied oil. On the basis of the buoyancy of OSA and the ecotoxicological effects on pelagic and benthic community, the priority areas for application of remediation techniques are Cachoeira, Maragogipe, and Salinas da Margarida because of the large amount of oil that accumulated at the bottom of the experiment flask (5.85%, 27.95%, and 38,98%; 4.2%, 17.66%, and 32.64%; and 11.82%, 8.07%, and 10.91% respectively).  相似文献   

Assessment of the geometry and volumes of small surface water reservoirs by remote sensing in a semi-arid region with high reservoir density     

Bruno Pereira  Till Francke  Geraldo Ramalho  Saskia Foerster  José Carlos De Araújo 《水文科学杂志》2019,64(1):66-79

Water fluxes in highly impounded regions are heavily dependent on reservoir properties. However, for large and remote areas, this information is often unavailable. In this study, the geometry and volume of small surface reservoirs in the semi-arid region of Brazil were estimated using terrain and shape attributes extracted by remote sensing. Regression models and data classification were used to predict the volumes, at different water stages, of 312 reservoirs for which topographic information is available. The power function used to describe the reservoir shapes tends to overestimate the volumes; therefore, a modified shape equation was proposed. Among the methods tested, four were recommended based on performance and simplicity, for which the mean absolute percentage errors varied from 24 to 39%, in contrast to the 94% error achieved with the traditional method. Despite the challenge of precisely deriving the flooded areas of reservoirs, water management in highly reservoir-dense environments should benefit from volume prediction based on remote sensing.  相似文献   

Mercury fluxes between an impacted coastal lagoon and the Atlantic Ocean   总被引：1，自引：1，他引：0  

P. Pato  C. Lopes  M. Vlega  A.I. Lilleb  J.M. Dias  E. Pereira  A.C. Duarte 《Estuarine, Coastal and Shelf Science》2008,76(4):787-796

The objective was to estimate the seasonal and inter-tidal variability of dissolved and particulate mercury fluxes between the Ria de Aveiro (Portugal) and the Atlantic Ocean. The mercury fluxes were estimated by means of a two-dimensional vertically integrated hydrodynamic model. Results showed that the particulate fraction plays an important role in the transport of mercury while the contribution of the seston fraction to the transport of mercury was always <0.5%. During spring tides, in summer, about 2% of mercury transported in seston was present in an organic form. The mass balance for the mercury fractions revealed that the mercury export to the Atlantic Ocean varied with season and tidal regime, mainly in terms of the relative importance of the dissolved and particulate fractions. An approximate range of values for the annual mass balance between 42 and 77 kg shows that the export of dissolved and particulate mercury makes little impact on the near shore region of the Atlantic Ocean and that the recovery of the lagoon from mercury contamination is likely to remain a long-term issue.  相似文献   

Decoupling the effects of deforestation and climate variability in the Tapajós river basin in the Brazilian Amazon          下载免费PDF全文

Mauricio E. Arias  Eunjee Lee  Fabio Farinosi  Fabio F. Pereira  Paul R. Moorcroft 《水文研究》2018,32(11):1648-1663

Tropical river basins are experiencing major hydrological alterations as a result of climate variability and deforestation. These drivers of flow changes are often difficult to isolate in large basins based on either observations or experiments; however, combining these methods with numerical models can help identify the contribution of climate and deforestation to hydrological alterations. This paper presents a study carried out in the Tapaj?s River (Brazil), a 477,000 km² basin in South‐eastern Amazonia, in which we analysed the role of annual land cover change on daily river flows. Analysis of observed spatial and temporal trends in rainfall, forest cover, and river flow metrics for 1976 to 2008 indicates a significant shortening of the wet season and reduction in river flows through most of the basin despite no significant trend in annual precipitation. Coincident with seasonal trends over the past 4 decades, over 35% of the original forest (140,000 out of 400,000 km²) was cleared. In order to determine the effects of land clearing and rainfall variability to trends in river flows, we conducted hindcast simulations with ED2 + R, a terrestrial biosphere model incorporating fine scale ecosystem heterogeneity arising from annual land‐use change and linked to a flow routing scheme. The simulations indicated basin‐wide increases in dry season flows caused by land cover transitions beginning in the early 1990s when forest cover dropped to 80% of its original extent. Simulations of historical potential vegetation in the absence of land cover transitions indicate that reduction in rainfall during the dry season (mean of ?9 mm per month) would have had an opposite and larger magnitude effect than deforestation (maximum of +4 mm/month), leading to the overall net negative trend in river flows. In light of the expected increase in future climate variability and water infrastructure development in the Amazon and other tropical basins, this study presents an approach for analysing how multiple drivers of change are altering regional hydrology and water resources management.  相似文献   

Distribution patterns of macrobenthic species in relation to organic enrichment within aquaculture earthen ponds   总被引：1，自引：0，他引：1  

Carvalho S  Barata M  Pereira F  Gaspar MB  Cancela da Fonseca L  Pousão-Ferreira P 《Marine pollution bulletin》2006,52(12):1573-1584

The relationship between organic enrichment and macrobenthic colonization patterns was investigated during an 8-month period in Diplodus sargus (white seabream) production ponds. A stratified sampling design was applied and each pond was divided into three zones: water entrance (WE); central (C); and automatic feeder zones (AF). Generally, the number of species and Shannon–Wiener diversity increased from the WE to the AF zone. Abundance did not present a clear trend. The recently developed marine biotic index (AMBI) was applied and showed to be sufficiently robust to discriminate, within a relatively small area, differences in macrobenthic communities due to organic enrichment. Nevertheless, caution is advised when applying this index or others based on ecological group’s assignment, as the classification of a certain area may differ when allocating a certain species to an unsuitable group. This is particularly evident when common species are involved.  相似文献   

Can Nassarius reticulatus be used as a bioindicator for Hg contamination? Results from a longitudinal study of the Portuguese coastline     

Coelho JP  Pimenta J  Gomes R  Barroso CM  Pereira ME  Pardal MA  Duarte A 《Marine pollution bulletin》2006,52(6):674-680

The focus of this work is to explore the use of the netted whelk, Nassarius reticulatus (L.), as an indicator of mercury (Hg) contamination, by assessing the concentration of Hg in the sediments and in the whelk along the entire Portuguese coast. Total Hg concentrations ranged from below the detection limit (0.01 ng absolute mercury) up to 0.87 mg kg(-1) dry weight (dwt) in sediments and between 0.06 and 1.02 mg kg(-1) (dwt) for organisms, with no significant differences between males and females. Although organic mercury was not detected in the sediments, it represented, on average, 52% of the total Hg in the whelk tissues, and as high as 88% in some cases, suggesting mercury accumulation from dietary intake. Significant negative correlations were found between the total Hg concentrations in the sediments and the log(10) of Hg concentrations in whelk tissues males (r=-0.64; P<0.01) and females (r=-0.52; P<0.01) indicating that the species is a poor indicator of Hg contamination. Nevertheless, since the highest concentrations of organic mercury in the whelk tissues were found in the least contaminated areas, this species must be highly relevant in the trophic web, namely on the possible biomagnification of mercury. The high dietary mercury accumulation from feeding on carrion and the low bioavailability of mercury to whelks in estuarine sediments may be the basis of the mercury accumulation pattern in N. reticulatus.  相似文献   

Cluster analysis applied to the spatial and temporal variability of monthly rainfall in Mato Grosso do Sul State,Brazil     

Paulo Eduardo Teodoro  José Francisco de Oliveira-Júnior  Elias Rodrigues da Cunha  Caio Cezar Guedes Correa  Francisco Eduardo Torres  Vitor Matheus Bacani  Givanildo Gois  Larissa Pereira Ribeiro 《Meteorology and Atmospheric Physics》2016,128(2):197-209

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Wildfire effects on extractable elements in ash from a Pinus pinaster forest in Portugal          下载免费PDF全文

Paulo Pereira  Xavier Úbeda  Deborah Martin  Jorge Mataix‐Solera  Artemi Cerdà  Maria Burguet 《水文研究》2014,28(11):3681-3690

The aim of this work is to study the effects of a wildfire on water‐extractable elements in ash from a Pinus pinaster forest located in Portugal. The pH, electrical conductivity (EC), calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), potassium (K⁺), sodium and potassium adsorption ratio (SPAR), aluminium (Al³⁺), manganese (Mn²⁺), iron (Fe²⁺), zinc (Zn²⁺), sulphur (S), silica (Si) and phosphorous (P) were analysed in ash sampled from a sloped area burned in a wildfire and from litter from a contiguous unburned area, with similar morphological conditions. The results showed that ash leachates had higher pH and EC, and were significantly richer in water‐extractable Ca²⁺, Mg²⁺, Na⁺, K⁺, SPAR, S and Si and significantly poorer in water‐extractable Al³⁺, Fe²⁺, Mn²⁺ and Zn²⁺ than litter solutions. No significant differences were observed in water‐extractable P. The fire changed the ash solute chemistry compared with the unburned litter and increased the sample variability of nutrient distribution with potential implications for plant recovery. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Diffuse volcanic gas emission and thermal energy release from the summit crater of Pico do Fogo,Cape Verde     

Samara M. Dionis  Gladys Melián  Fátima Rodríguez  Pedro A. Hernández  Eleazar Padrón  Nemesio M. Pérez  Jose Barrancos  Germán Padilla  Hirochika Sumino  Paulo Fernandes  Zuleyka Bandomo  Sónia Silva  José M. Pereira  Hélio Semedo 《Bulletin of Volcanology》2015,77(2):1-13

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