Navegando por Assunto "Degradation"

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Acesso aberto (Open Access)
The mineralogy and chemistry of the German and Portuguese tiles used to face a historic building in the Amazon region and their natural susceptibility to tropical weathering
(Instituto Nacional de Pesquisas da Amazônia, 2013-09) COSTA, Marcondes Lima da; SANJAD, Thais Alessandra Bastos Caminha; PAIVA, Rosildo Santos
During the 19th century, the most prominent buildings of the city of Belém were faced entirely with tiles manufactured in Portugal and Germany, which now exhibit distinct degrees of degradation. The Pinho mansion is one of the most important of these buildings and was selected for the investigation of the action of the tropical Amazonian climate on the degradation of the tiles. To achieve this objective, the tiles were mapped for organic and inorganic degradation, and samples were collected for analysis. The minerals were determined by XRD, the chemical composition by classical wet methods and SEM/EDS, and the microorganisms under the microscope. The results show that the German and Portuguese tiles are quite different in their composition. While both ceramic bodies are composed of SiO2 and Al2O3, CaO was found only in the Portuguese tile. The low Na2O and K2O contents indicate the addition of materials to reduce the fusion temperature. SiO2 and PbO are the main constituents of the glaze, with CoO and FeO being added as pigment. The ceramic body of the German tiles is constituted of quartz, mullite, and cristobalite, in contrast with the Portuguese tiles, which are made of quartz, gehlenite, diopside, calcite, and feldspars. The glazes are XRD-amorphous. The chemical and mineralogical differences between the German and Portuguese tiles indicate that they were produced from different raw materials under distinct thermal processes. The most prominent weathering-related modifications are the thin layers (German tiles), oxidation stains, dark stains, the detachment of the tile (Portuguese tiles), loss of the glaze and powdering of the ceramic body (Portuguese tiles) through the establishment of Cyanophyta and Bacillariophyta.. The distinct degradation patterns of the tiles exposed to the tropical Amazon climate are a consequence of their distinct mineralogy and chemistry.
Acesso aberto (Open Access)
Petrechos de pesca como resíduo praial em uma área de proteção ambiental na costa paraense
(Universidade Federal do Pará, 2024-02-29) SILVA, Elaine Simone da Cruz Silva; LOUREIRO, Sarita Nunes; http://lattes.cnpq.br/1473112723704086; MONTEIRO, Sury de Moura; http://lattes.cnpq.br/4309806566068586; https://orcid.org/0000-0001-9449-7043
Abandoned, Lost or otherwise Discarded Fishing Gear (ALDFG) during fishing activities represent a global problem. This equipment corresponds to at least 640,000 tons of waste that accumulates annually in the oceans and causes impacts on aquatic fauna such as entanglement, ingestion, injuries, ghost fishing and can also act as vectors of chemical substances. This is the first quantification of ALDFG on beaches in Northern Brazil. The study was carried out on beaches on Algodoal Island, which is an Environmental Protection Area (APA), with the aim of evaluating whether there is spatial and temporal variation in ALDFG on different beaches (Caixa d´água, Farol, Princesa and Cação), considering their different environmental characteristics, and check whether there is the occurrence of organisms associated with ALDFG. The ALDFG were collected in the rainy and dry seasons (2022), in quadrants of 100m² in 30 transects containing three points: high tide line, intermediate and low tide line. The density of ALDFG and an Environmental Impact Factor (FIA) were calculated, considering the type of ALDFG, its mass and the environment where it was found. In total, 459 ALDFG items were collected (248 in the dry season and 211 in the rainy season), totaling 13.14 kg, among which the main ones were fragments, electrical cables, ropes and fishing nets, with emphasis on the nylon type material and blue color. Overall, the beaches had an average density of 0.023 items/m² and 0.755 g/m² in the rainy season and 0.028 items/m² and 0.704 g/m² in the dry season, with a low environmental impact (FIA between 0-1). But points with high impacts were also observed (FIA = 10 and FIA = 9), in points with the presence of rocky outcrops and vegetation, respectively. On Caixa d'água beach there is the presence of juvenile mangroves in the intertidal environment and rocky outcrops, as well as, it is located close to the port for fishing vessels, therefore, it was the beach that presented the largest quantity of ALDFG (274 items), the highest mass (6.35 kg), the highest density (2.74 items/m² and 63.52 g/m²), and consequently the highest Environmental Impact Factor (FIA = 10). Furthermore, associated with the ALDFG, 1,543 organisms were recorded (1,380 in the rainy season and 163 in the dry season) belonging to the following groups, barnacles, bivalves, paguros, crabs, isopods, polychaetes, gastropods, anemones and sea fleas, the majority of which were found associated with ropes and polystyrene buoys. Fishing is a recognized source of ALDFG and the presence of these residues in an APA can cause several impacts to this ecosystem..