Prospecção magnetométrica em intrusiva básica com indícios de mineralização aurífera no município de São Sepé - RS

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Magnetometric exploration in intrusive basic with evidence of gold in northern region of the Camaquã Sedimentary Basin (RS)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diet and capture of Hypostomus strigaticeps (Siluriformes, Loricariidae) in a small brazilian stream: relationship with limnological aspects

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Assessment of chromium contamination in the Monte Alegre stream: a case study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Botryoidal platinum, palladium and potarite from the Bom Sucesso stream, Minas Gerais, Brazil: Compositional zoning and origin

Platinum-Pd nuggets from the Born Sucesso stream alluvium Minas Gerais, Brazil. have been investigated by electron-probe microanalysis. The nuggets attain 1 mm in maximum dimension and have a botryoidal habit, with pronounced compositional core-to-margin zoning of internal structures, Although there is a wide variation in internal morphology and individual zones vary markedly in thickness (<1-100 mum), a typical composite arborescent nugget comprises a broad irregular core region of massive auriferous Pd-Hg alloy (potarite delta-PdHg) or cavity space + relict potarite enclosed by a narrow zone of platiniferous, palladium or alloy of near Pt50Pd50 composition, and is progressively oscillatory zoned by palladian platinum, with growth eventually enveloping the whole botryoidal colony, to a narrow rim of palladian platinum or pure platinum. Other nuggets comprise an arborescent to dendritic core of auriferous potarite, a broad internal zone of either pure platinum or palladian platinum, and a narrow rim of platinum, the mineral palladium contains up to about 65 at.% Pd; this is the first detailed modern confirmation of palladium in its type locality. Auriferous potarite ranges in composition from similar toPd(3)Hg(2) to near Pd(Hg,Au). The origin of these nuggets remains unclear, but their mineralogy is broadly equivalent to that of palladian gold. potarite and platinum in alluvial sediments and overburden from Devon, England, which are considered to be detrital, and their platinum-group-clement geochemistry is consistent with precipitation from hydrothermal fluids. We suggest that the Bom Sucesso nuggets resulted from high-level episodic hydrothermal alteration of mafic and ultramafic rocks within the drainage basin, with the remobilized Pt and Pd precipitated in open spaces in the enclosing metaquartzites.

Influence of a Brazilian sewage outfall on the toxicity and contamination of adjacent sediments

The submarine sewage outfall of Santos (SSOS) is situated in the Santos Bay (São Paulo, Brazil) and is potentially a significant source of contaminants to the adjacent marine ecosystem. The present study aimed to assess the influence of SSOS on the sediment toxicity and contamination at Santos Bay. At the disposal site, sediments tended to be finer, organically richer and exhibited higher levels of surfactants and metals, sometimes exceeding the Threshold Effect Level values. The SSOS influence was more evident toward the East, where the sediments exhibited higher levels of TOC, total S and metals during the summer 2000 sampling campaign. Sediment toxicity to amphipods was consistently detected in four of the five stations studied. Amphipod survival tended to correlate negatively to Hg, total N and % mud. This work provides evidence that the SSOS discharge affects the quality of sediments from Santos Bay, and that control procedures are warranted. (c) 2005 Elsevier Ltd. All rights reserved.

Effects of dredging operations on sediment quality: contaminant mobilization in dredged sediments from the Port of Santos, SP, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ecotoxicological assessment of sediments from the Santos and São Vicente estuarine system- Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ecotoxicological assessment of sediments from the Port of Santos and the disposal sites of dredged material

A dragagem dos sedimentos do Canal de Santos é necessária para permitir o trânsito de navios que operam no Porto de Santos. As áreas de disposição do material dragado estão situadas na zona costeira, em frente à Baía de Santos. Este estudo visou avaliar a qualidade dos sedimentos do Canal de Santos e das áreas de disposição atuais e antigas, utilizando testes de toxicidade de sedimento integral com anfípodos e de toxicidade de elutriatos com embriões de ouriço do mar. As amostras do Canal de Santos foram consideradas as mais tóxicas: todas as amostras dessa área foram consideradas significativamente tóxicas. Além disso, algumas amostras das áreas de disposição exibiram toxicidade. Os resultados mostraram, portanto, que os sedimentos apresentam evidências de degradação em sua qualidade, porém novos estudos devem ser conduzidos visando determinar as relações entre contaminação e toxicidade. Os resultados sugerem ainda que a disposição dos sedimentos dragados deva ser reavaliada.

Contamination of port zone sediments by metals from Large Marine Ecosystems of Brazil

Sediment contamination by metals poses risks to coastal ecosystems and is considered to be problematic to dredging operations. In Brazil, there are differences in sedimentology along the Large Marine Ecosystems in relation to the metal distributions. We aimed to assess the extent of Al, Fe, Hg, Cd, Cr, Cu, Ni, Pb and Zn contamination in sediments from port zones in northeast (Mucuripe and Pecem) and southeast (Santos) Brazil through geochemical analyses and sediment quality ratings. The metal concentrations found in these port zones were higher than those observed in the continental shelf or the background values in both regions. In the northeast, metals were associated with carbonate, while in Santos, they were associated with mud. Geochemical analyses showed enrichments in Hg, Cd, Cu, Ni and Zn, and a simple application of international sediment quality guidelines failed to predict their impacts, whereas the use of site-specific values that were derived by geochemical and ecotoxicological approaches seemed to be more appropriate in the management of the dredged sediments. (C) 2012 Elsevier Ltd. All rights reserved.

Harmonised framework for ecological risk assessment of sediments from ports and estuarine zones of North and South Atlantic

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Habitat use, reproductive traits and social interactions in a stream-dweller treefrog endemic to the Brazilian Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Environmental adaptation of the source of the subbasin of Rico Stream, Monte Alto - SP, Brazil

Este trabalho teve como principal objetivo definir padrões fotográficos que representem o uso e a ocupação do solo da cabeceira de drenagem do Córrego Rico, localizada no Município de Monte Alto, Estado de São Paulo, para fins de adequação ambiental no que tange à legislação florestal brasileira. O mapeamento foi realizado utilizando técnicas de sensoriamento remoto e interpretação visual da imagem World View, seguida da digitalização da rede de drenagem e vegetações (naturais e agrícolas) no AutoCad, com auxílio de documentos e trabalho de campo. A área de estudo apresenta uma superfície de 2.141,53 ha, e os resultados permitiram constatar que a principal cultura é a cana-de-açúcar, com 546,34 ha, seguida de pastagens, com 251,22 ha, culturas perenes, com 191,71 ha, Eucalipto, com 57,31 ha, e a cebola, com 49,52 ha da área total, confirmando o avanço dos canaviais na região. A área possui 375,04 ha de áreas de preservação permanente (APPs), e desta superfície verificou-se que apenas 72,17 ha (19,24%) encontram-se compostos por vegetação arbórea ou mata, e destas 302,87 ha precisam ser enriquecidos e reflorestados com vegetação nativa da região, de acordo com legislação vigente. Os dados de área possibilitam futuras propostas de modelos de adequação ambiental para a microbacia, de acordo com a legislação ambiental vigente.

Spatial variations at different observational scales and the seasonal distributions of stream macroalgae in a Brazilian subtropical region

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Longitudinal distribution and seasonality of macroalgae in a subtropical stream impacted by organic pollution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)