BDTD - Biblioteca Digital de Teses e Dissertações

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2289

Biblioteca Digital de Teses e Dissertações da UFPA (BDTD). Sistema Eletrônico de Teses e Dissertações (TEDE). Projeto BDTD/UFPA e Instituto Brasileiro de Informação em Ciência e Tecnologia (IBICT).

Navegar

Agora exibindo 1 - 20 de 1597

Acesso aberto (Open Access)
Acidentes com animais aquáticos em pescadores artesanais em um município da costa Amazônica: do levantamento ao tratamento
(Universidade Federal do Pará, 2019-06-18) SILVA, Patrícia Fernandes da; MARTINELLI FILHO, José Eduardo; http://lattes.cnpq.br/2080628833884538
Accidents with aquatic animals may occur whenever men invade the animal’s environment or handle it without proper care. Many studies reported cnidarians, stingrays, catfishes, toadfishes and others as dangerous to man, nevertheless information is scarce and inconclusive for the Brazilian North region. The frequency of accidents is probably high at the Pará state since fisheries is an important activity, although the cases are not adequately registered. Artisanal fisheries are an economic and socially important activity for the coastal municipalities in the Brazilian Amazon and gathers a great number of fishermen. Artisanal fishermen, are thus associated to a great risk of accidents caused by aquatic animals. The present study analyzes the frequency and variability of the occurrence of accidents with aquatic animals on artisanal fishermen, and related to different fishing strategies. It also explores the ethnobiological knowledge about the causative animals, treatment methods and accidents prevention. Data was collected at São Caetano de Odivelas municipality (Pará state), where traditional communities are sustained by artisanal fisheries. A total of 154 interviews were collected, gathering socioeconomic and ethnobiological information about accidents with aquatic animals. Accidents occurred in 98,7% of the interviewers and were associated to the daily labor from artisanal fisheries. Stingrays, catfishes and toadfishes were responsible for the most of the accdients (81,6%), independent from the different fishing strategies. The search for medical care was uncommon after a accident (26,3%) and the recommended medical procedures were no adopted by the fishermen. The number of accidents was higher with a lower scholar level among the fishermen (p < 0,001). In order to reach the artisanal fishermen, a didactical product (a calendar) was developed, with information to aid the avoidance, treatment and procedures after an accident with an aquatic animal.
Acesso aberto (Open Access)
Acidentes com transportes hidroviários e os extremos meteorológicos no nordeste da Amazônia
(Universidade Federal do Pará, 2015-03-30) SANTOS, Suanne Honorina Martins dos; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401
This study analyzed the accidents with waterway transport passengers and cargo in the period 2008 to 2013, as a result of extreme weather occurring in the northeast Amazon, often with serious consequences the structure of vessels and especially the loss of human life. Based on data from the Flagship of the Eastern Amazon Ports, referring to the investigation of accidents facts of navigation, can be characterized in that period these accidents occur more and the distribution of these accidents in time and space, through sub-areas called 1, 2 and 3, where they are ranked the most common accidents in Subarea 1 type shipwreck where the basin of Marajó is located with features of larger rivers, in Subarea 2 and 3 of collision type where the morphological characteristics of rivers are narrower as well, in addition to these results was obtained in relation to rainfall in the rainy season (December to May) as the most responsible for accidents occurring during this period that suffers strong influence of precipitation systems as the Intertropical Convergence Zone, Mesoscale Convective Systems, instability lines and vortex of Advanced Levels and the less rainy season (June to December) the wind is regarded as the main variable that causes accidents in the waterway mode, especially during the intensification of the northeast trade winds, which are a free atmosphere of instability, accidents tend to occur more frequently in the time from 12 to 24 hours. Thus, with the precipitation climatology with the National Institute of Meteorology data, one can show through the climatology of the precipitation field of study, decreased quantity of deeper into sub-areas of the continent. The wind in the less rainy period acts with greater intensity in Subarea 1, the highest number of victims focuses on children and adults, mostly with men. It also presented an approach based on the socioeconomic aspects inherent risks of naval vessels with steel hulls and wood, the latter being the reality of the Amazon, which ultimately victims the more people and have more easily collapse structure, thus being potential threat to safety of navigation of cargo and passengers taking into account socioeconomic characteristics, although the vessels with the highest number of accidents has been pushers ferries built in naval steel. In this sense, the primary aid weather forecasting may decrease the favorable conditions for the occurrence of accidents with waterways vessels, because the lack of atmospheric conditions by those who pilot vessels is notoriously poor, because this lack of knowledge the chances of accidents are high, influencing the socioeconomic aspects of passengers and owners of vessels navigating the rivers belonging to the Marajó Bay, Tocantins, Pará and Amazonas river, which were the waterways studied in this dissertation.
Acesso aberto (Open Access)
Ações de educação ambiental na sensibilização da qualidade da água para consumo humano no assentamento Palmares, no município de Araguatins, Tocantins
(Universidade Federal do Pará, 2018-05-22) LIMA, Lílian Natália Ferreira de; SILVA, Cleber Silva e; http://lattes.cnpq.br/7673237583688618
The importance of assessing the quality of water for human consumption is based on the fact that it is one of the main vehicles of infectious diseases. The objective of this research was to evaluate the quality of the water for human consumption, by means of the physical, chemical and microbiological characterization of the water of open and closed wells of the settlement Palmares, Araguatins (TO) and to develop an educational campaign based on the results obtained in the study, based on environmental education. The physical, chemical and microbiological parameters were collected during the period from October 16 to 20 in two wells of the settlement, using the multiparameter probe, turbidimeter, Ph meter, thermometer. The results obtained were compared with the resolution of the Ministry of Health nº 2.914 of 12/12/2011. The analyzed data of the wells of the settlement Palmares indicate that there is change in the behavior of some parameters. These changes were observed in the values of salinity (NaCl) that presented concentrations above the maximum concentrations allowed by Ministerial Order Nº 2.914 of 12/12/2011, the analysis of variance did not recognize the existence of significant differences between the collections of the mean values of the campaigns sampled from all groundwater parameters of the open and closed wells studied, indicating that there were no methodological errors, accepting the null hypothesis. According to Ordinance Nº 2.914/11/MS, results obtained in this study were unfit for human consumption, since the values of salinity, pH and E coli did not meet the potability standards, indicating contamination by organic matter. Still, it is concluded that the families of the palm groves are consuming water outside the potability standards stipulated by the Brazilian legislation and that the improvement of the quality of the water offered goes through the diffusion of sanitation technologies and the use of efficient methodologies for environmental education of the inhabitants of the settlements.
Acesso aberto (Open Access)
Ações educativas à proteção e conservação dos mananciais Bolonha e Água Preta do Parque do Utinga.
(Universidade Federal do Pará, 2023-09-28) SANTOS, ALTEMAR PEREIRA DOS; SANTOS, DAVIS CASTRO DOS; http://lattes.cnpq.br/7784257182257171; https://orcid.org/0000-0003-0375-6949
.Faced with the complex environmental context that we experience today, this study proposes to highlight the problem of solid waste in the school environment, considering that basic education institutions are configured as a space for the community, for cognitive and social development, responsible for the formation of their students, and the environment is conducive to the dissemination of awareness for the preservation of the environment. That said, the present research seeks to promote environmental education through the construction of ludic pedagogical teaching material, starting from the problem of urban solid waste. The target audience will be students from the 5th year of Elementary School at the Rotary Municipal School, located in the Condor neighborhood, on the outskirts of Belém-Pa. The aim is, with the applied methodology, to instigate the interest of the students in the issue, to build a competition that can approach the theme in a playful and productive way and, finally. To elaborate an educational product (game script) that can disseminate the proposal to other Institutions
Acesso aberto (Open Access)
Acúmulo e exportação de carbono, nitrogênio, fósforo e metais em canais de maré dos manguezais de Marapanim, Costa Norte Brasileira
(Universidade Federal do Pará, 2020-12-18) MATOS, Christiene Rafaela Lucas de; SILVA, José Francisco Berrêdo Reis da; http://lattes.cnpq.br/1338038101910673; https://orcid.org/0000-0002-8590-2462; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
In this study, we assessed the potential of intertidal mudflat sediments along mangrove forest to accumulate and export carbon, nutrients (N and P) and metals (Fe and Mn), in addition to examine the influence of the Amazonian seasonal rainfall patterns on the physicochemical conditions, diagenetic processes and exchange of nutrients and metals along the sediment-water interface (SWI) in intertidal mudflats fringed by pristine mangroves. The study was carried out in the Marapanim River estuarine system (northern Brazil), which is fringed by extensive areas of well-developed mangroves, part of the largest continuous and best preserved mangrove forest in the world, located approximately 200 km from west of the mouth of the Amazon River. The results of this work are presented in two articles. The first deals with the potential of stocks and accumulation of COT, NT and PT in intertidal mudflat sediments, in addition we investigate the potential sources of sedimentary organic matter (OM). The second assesses the influence of seasonal rainfall pattern on physicochemical properties, the diagenetic processes and the diffusive fluxes of nutrients at the SWI in the Marapanim mangrove creeks. During wet season the salinity values decreased as a consequence of the increase in rainfall, with a dilution-mixing zone in the top sediment (<15 cm). In the dilution-mixing zone, Fe (III) and Mn (IV) reduction are the dominant anaerobic respiratory processes in the sediments. The redox zonation of sediments oscillated in response to the rainfall patterns, with the highest concentrations of Fe2+ and Mn2+ in deeper sediment layers during the dry season. Under suboxic conditions, the mudflat sediments act as a source of Fe2+, Mn2+, NH4 +, and PO4 3- to the water column, and these fluxes were driven by rainfall. The results indicated that mangrove-fringed mudflats are quite effective in retaining carbon, nutrients and iron in sediment solid phases than exporting to the coastal waters, while can potentially be a significant contributor to the oceanic Mn cycle. The potential of these mangrove creeks to accumulate these elements is directly related to grain size, sources and susceptibility of OM degradation. In addition, temporal variability in pyrite formation revealed that the solid phase retention mechanisms are also susceptible to seasonal effects, with lower concentrations of chromium-reducible sulfur (CRS, mainly pyrite fraction) during the dry season. Therefore, we show that these seasonal variabilities implied substantial changes of physicochemical properties and the diagenetic processes, affecting the release of metals and nutrients from the SWI and their accumulation in the sediment.
Acesso aberto (Open Access)
Acúmulo e fracionamento de fósforo nos sedimentos do estuário do rio Coreaú (Ceará) para avaliação do impacto da carcinicultura
(Universidade Federal do Pará, 2014-11-17) AQUINO, Rafael Fernando Oliveira; KAWAKAMI, Silvia Keiko; http://lattes.cnpq.br/5306256489815710; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
The shrimp culture (shrimp farms) is one of the activities of aquaculture widely employed in Brazilian estuaries and mangroves. The shrimps are fed with phosphate enriched compounds. Thus, the effluent produced by farms can accelerate the eutrophication process. An increase of shrimp farming has been seen in Coreaú River Estuary, state of Ceará, but data about environmental quality are scarce to allow monitoring of the region. The aim of the present research was to assess the contribution of the shrimp farms on phosphorus input to the Coreaú River Estuary. The main forms of phosphorus: bioavailable (P-Exch); bound to iron oxy-hydroxides (P-Fe), on the biogenic, autigênica carbonates and apatite (P-CFAP), on the detrital apatite (P-FAP) and organic phosphorus (P-Org) and as well as total organic carbon (%TOC) and chlorophyll-a were determined in samples of surface sediments and cores from the margins of the Coreaú River Estuary. The high concentrations of P-Total in surface sediments indicated the need for monitoring studies. The larger fraction was P-Fe, composing 30% of P-Total, approximately. These results indicate the ability of the iron oxy-hydroxides to immobilize or release phosphorus. The contribution of the farm’s effluents was evidenced by higher concentrations of P-Org in points adjacent to discharge areas. In sediment cores, the highest P-Total concentrations were found predominantly in fine sediments (silt and clay), with the P-Fe, P-CFAP and P-FAP fractions being the main contributors. The sedimentation rates and concentration increases of P-Total indicate the possible period of deforestation and starting or maximum activity of shrimp farms in the end of the 1980 and mid 1990, respectively. High phosphorus concentrations as well as %TOC and chlorophyll-a levels suggested a significant anthropogenic contribution, associated with a high potential for eutrophication.
Acesso aberto (Open Access)
Adaptação do método de Bott para contraste de densidade variando com a profundidade
(Universidade Federal do Pará, 2013-08-23) GOMES, Karina Palheta; SILVA, João Batista Corrêa da; http://lattes.cnpq.br/1870725463184491; SANTOS, Darcicléa Ferreira; http://lattes.cnpq.br/5813659873067927
We present a new method to estimate the basement relief of a sedimentary basin through the analytic extension of the expression of the slab Bouguer for the case of a density contrast between the basement and the sediments decreasing monotonically with depth according to a hyperbolic law. The method requires that the noise in data have a standard deviation smaller than 0.01 mGal. The basement relief estimates are obtained at positions located directly below each observation. The methodology was applied on synthetic data from a simulated sedimentary basin presenting smooth basement relief. The method produced estimated basement topographies close to simulated basement topographies. The method was also applied to three sets of real Bouguer anomalies: Recôncavo Basin (Brazil), Büyük Menderes Graben (Turkey) and San Jacinto Graben (United States). The solutions produced by the proposed method attained maximum basement depth estimates in accordance with the available geological information: 6 km to Reconcavo Basin, 1.6 km to Büyük Menderes Valley, and 2.2 km to San Jacinto Graben.
Acesso aberto (Open Access)
Adequação de método para avaliação de risco de contaminação ambiental em áreas de estocagem de combustíveis
(Universidade Federal do Pará, 2002-02-28) CHAVES, Cláudio Cezar Cunha de Vasconcelos; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
Acesso aberto (Open Access)
Adsorção de cromato em materiais sintetizados a partir de rejeito de caulim do rio Capim
(Universidade Federal do Pará, 2008-05-13) MORAES, Milena Carvalho de; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
Industrial and domestic waste cause serious problems for the environment. Industries treatment of kaolin have been deposited reject in large lakes of sedimentation and this has caused accidents as occurred in august/2007 and February/2008. The large volume of kaolin in the lakes sedimentation invaded lakes and rivers from Rio Capim, Para region. This fact resulted in the pollution of waters and death of fish. This problem can be minimized with the use of kaolin reject (KR) in the synthesis of new materials. In this work was used KR treated with organic acid (glycine at concentrations of 5%, 10% and 15% , being obtained the adsorbents: KR-gly-5, KRgly-10 and KL-gly-15, respectively) and mixture NaClO4:HClO4 (proportions 1:50 and 1:75, being obtained the adsorbents KR-NaClO4:HClO4-1:50 and KR- NaClO4:HClO4- 1:75, respectively) and KR as source of Si and Al in the synthesis of zeolites. The materials were characterized by chemical composition and XRD, FTIR, DTA-TG and SEM data. These materials were studied in adsorption process for CrO4 2- from aqueous solutions. The results obtained indicate that the CrO4 2- is adsorbed by kaolin reject and other materials from KR followed this order: KR-gly-10> KR-gly-5>KR-gly-15>KG> KR- NaClO4:HClO4- 1:75> zeolites.
Acesso aberto (Open Access)
Adsorção de molibdato em minerais de argila delaminados e amorfizados
(Universidade Federal do Pará, 2012-04-15) PEREIRA, Patricia Magalhães; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
The search for efficient methodologies to control environmental pollution, as well as the development of technologies in the fields chemical, physical and biological have been widely discussed in order to produce efficient alternatives to improve the quality of life and control of chemical pollutants (organic or inorganic) that over the years are being dumped into the environment so as inconsequential by households and industries. Thus, it is important to know about the adsorptive behavior of metals in the soil, because high concentrations of metals produce adverse effects on the environment. Molybdenum is an essential element for biological functions of plants and animals, but in high concentrations in the body can lead to bone deformities, anemia, abnormal liver and lead to death.The possibility of interaction of organic-inorganic compounds (Humic Acid, Urea andH2SO4) in sediments "in nature” from the region of Acre, was investigated with the aim of evaluating the possibility of applying these materials in adsorption processes in molybdate aqueous solutions. The natural samples used in this study have a high content of clay minerals, mainly smectite, kaolinite and low content of primary minerals such as feldspar and quartz. All samples "in nature" were characterized by XRD, XRF, FTIR, SEM and pHH2O and pHKCl. The modification with inorganic acid concentrations (0.25, 0.5, 1 and 1.5mol.L-1), temperature and contact time are important parameters in the process of delamination of the clay minerals. As the use of organic compounds such as urea and humic acid were efficient in the amorphization. The study by XRD in the modified samples show a change in the structure when H2SO4 at the concentrations used, but this fact is only observed for 15Å peak, characteristic of smectite, all other peaks showed no significant change. The synthesis of organic compounds promoted the amorphization of the smectite peak reference. Thus, as the sediment naturally has clay (smectite, kaolinite), confirmed by XRD and the presence of iron, indicating a transition to the montmorillonite nontronite, and with isomorphous substitution of iron is expected to strong interaction between the adsorption molybdate fractions modified with respect to the natural. The introduction of H+ due to the modification process with sulfuric acid promoted the replacement of calcium ions in the structure confirmed by semi-quantitative analysis performed by EDS. SEM analysis indicated the presence in natural samples cluster morphology, this fact was not observed in the modified samples, which was observed delamination and amorphization. The equilibrium conditions in the adsorption process were investigated in which it is inserted, time of 2 h and the solution pH was measured before and after adsorption. The equilibrium datawere represented by theisotherm models Langmuir, Freundlich and Sips. The adsorption process had better performance in the concentrations for samples and S10H15 S10UH. The humic acid modified samples contained higher Qmáx =3.43, values regression fit to the model obtained indicate Freundlich efficient adsorption process, the modified samples effective adsorbed molybdate anion in comparison to natural sample.
Acesso aberto (Open Access)
Adsorção de nitrato em rejeito de caulim organofuncionalizado com uréia
(Universidade Federal do Pará, 2012-05-30) TAVARES, Laís Conceição; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
Kaolin waste, generated in abundance by companies from Pará state, has caused to the environmental problems. In order to give input on the reuse of this waste was evaluated retention of nitrate ions on kaolin waste natural and modified with urea and studied the equilibrium of adsorption processes at solid-solution interfaces. The materials were characterized by X-ray diffraction and X-ray fluorescence (XRF and XRD, respectiely), IR spectroscopy (FTIR spectrum), scanning electron microscopy and estimated data of surface charge. Adsorption experiments of nitrate ions in the waste natural kaolin (CRJN) and modified with urea (CRJU) were performed without pH adjustment. H + concentrations were measured by direct potentiometry before and after the process of adsorption and equilibrium concentrations of nitrate were measured by ion chromatography. The results indicated: high purity kaolin waste; formation of kaolinite-urea complex confirmed by XRD reflection at 2  8,28o e d = 1.068 nm and the FTIR spectrum with the appearance of a broad band of low intensity, containing two discrete shoulder around 3500-3380 cm-1, corresponding to asymmetric and symmetric vibrations of the group-NH2 of urea-kaolinite, superimposed to the vibration of water. surface charges data, suggesting that the materials have a higher capacity to adsorb cations than anions, but depending on the concentration of H + and OH- on adsorbent, the hydroxyl surface can be protonated yielding positive charges that are reflected in the adsorption of anions, obtaining significant adsorbed nitrate, both in CRJN as CRJU (0,27-0,73 and from 0,18-0,70 3.5 mg g-1, respectively), the separation coefficient (RL) of from 0,28 to 0,828 change in free energy ΔG ° = -2,094 to + 0,445 kJ mol-1 for CRJN and ΔG° = -1,036 to + 1,32 kJ mol-1 for CRJN molecule. The data from RL indicated that the adsorption processes are less favorable in most points of the adsorption processes and based on the results of the free energy change (ΔG º) was showed low spontaneity to no spontaneity and adsorption processes are physical.
Acesso aberto (Open Access)
Adsorção de Pb por caulinita tratada com ácidos acético e cítrico
(Universidade Federal do Pará, 2005) SENA, Luciana Freitas de; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
Acesso aberto (Open Access)
Adsorção simultânea de íons níquel, zinco e cobre em sedimentos argilosos da Formação Solimões no estado do Acre
(Universidade Federal do Pará, 2011-09-02) CARDOSO, Vivian Mariana Miranda; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
Torrential rains in the Amazon region provide large leaching of micronutrients, which can be controlled from the adsorption reactions of micronutrients in clay minerals. Studies on the geochemical properties of sediment containing high concentrations of clay minerals in the adsorption reactions of micronutrients is a research topic of great importance considering the proven use of clay minerals with a wide range of applications in various processes and procedures adsorption, involving the remediation of sediment, purification of air and water. In order to make contributions on the physical and chemical properties of soils and applicability of the Solimões Formation from Acre State was carried out a study to simulate natural competitive adsorption of micronutrients cobre, níquel e zinco in different adsorbents sites present in these sediment and to evaluate the influence of the attributes mineralogical, chemical and physico-chemical from these adsorption processes. Preliminary data on the mineralogy of soil samples allowed to select four stations distributed among four named as H1RA, H6B, H23A H9F and located along the BR 364 and BR 317, as well as outcrops in the river Acre. Analyses of samples were performed by XRD (using the powder in the range 2θ=o 5-75 ; analysis of clay fraction in sheets oriented air-dried in an atmosphere of ethylene glycol o and heated at 550 ° C (2θ = 3 -35 ) analysis total chemical by ICP-OES; element analysis exchangeable and available to determine parameters of soil fertility. In adsorption experiments the equilibrium concentrations of cobre, níquel and zinco were determined by AAS. We used the models of Langmuir isotherm, Sips, Toth, Temkin Rendlich-Petersen and the fit of the experimental data of adsorption. The results indicated that the samples present as major minerals quartz and clay minerals of the smectite group, mica and kaolinite mineral and the 14th (H6B) preliminarily identified as interstratified mica-chlorite smectite-mica or chlorite-vermiculite. The other minerals identified in the samples were gypsum (H1RA), microcline (H6B and H9F) and albite (H9F). The average chemical composition is represented by 60.99% SiO2, 15.91% Al2O3, 5.84% of Fe2O3, 2.21% K2O, 0.34% of Na2O, 1.26% MgO, 0.86% CaO and 0.86% TiO2. The following ranges were obtained for the parameters of fertility: pHH2O = 5.24 to 8.36; pHKCl = 3.16 to 7.02; CTCefetiva = 3.37 to 25.42 cmol c / kg;% V (base saturation) = 83.08 to 97.63; saturation% Ca = 4.28 to 69.21; saturation% = 11.32 to 76.42 Mg, K saturation% = 2.32 to 17.32;. In the adsorption experiments were obtained the following ranges for the amount of each element adsorbed (mg / g) in soil samples selected: Cu) from 91.30 to 147.46 in H1RA, 47.25 to 83.93 in H6B , 67.13 to 137.36 in H9F; 73.01 to 141.35 in H23A, Ni) from 49.97 to 93.81 in H1RA; 42.51 to 113.44 in H6B; 62.52 to 134.86 in H9F; 54.13 to 172.58 in H23A, Zn) from 50.11 to 104.50 in H1RA, 44.31 to 64.12 in H6B; 60.21 to 89.91 in H9F; 73.84-135 , 60 in H23A. In these experiments was obtained the following values for the initial pH of the aqueous suspensions of samples in H1RA pHinicial=3.88 to 5.38; in pHinicial H6B = 2.71 to 3.27; H9F in pHinicial = 3.16 to 4, 24 and in pHinicial H23A = 2.61 to 3.29. The values of pH equilibrium were 4.38 to 5.2 in the H1RA sample, 2.71 to 3.16 in H6B; 3.24 to 4.2 in H9F; 2.51 to 3.14.in H23A. It was concluded that the sediment samples analyzed have suitable properties adsorptive for simultaneous retention of Cobre, níquel and zinco in water; the samples with montmorilonite (station H23A) and mineral 14A (H6B) present adsorption of metals transition at pH values between 2.5 and 3.1. The samples H1RA H9F with different groups of clay minerals (smectite, kaolinite and mica) the adsorption of transition metals occurs at pH values between 3.2 to 5.5. The ionic strength increases with decreasing pH . The best isotherm models to describe adsorption processes of Cobre, níquel and zinco in sediment samples were the Langmuir and Sips models. The values of ns Sips indicated that the majority of adsorption systems fall between the homogeneous heterogeneous systems. The equilibrium data and thermodynamic processes of simultaneous interaction between these ions and mineral adsorbents indicated that the processes are favorable, spontaneous and the type of adsorption is specific (chemical adsorption) with the formation of inner sphere complexes.
Acesso aberto (Open Access)
Aerossóis de queimadas e internações hospitalares por doenças respiratórias em crianças no Estado do Pará.
(Universidade Federal do Pará, 2021-05-31) MOURA, Maurício do Nascimento; SILVA, Glauber Guimarães Cirino da; http://lattes.cnpq.br/4792139391237534; https://orcid.org/0000-0003-1105-7603; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401; https://orcid.org/0000-0003-3253-5301
According to WHO, for every four deaths of children under 5 years, one is related to environmental pollution, which is equivalent to 93% of children living in environments with polluted atmosphere worldwide. This research investigated the variability of fires and hospital admissions for respiratory diseases in children under 9 years of age, in a region deeply marked by changes in land use across the planet, with consecutive years in the ranking of deforestation, followed by fire of forest biomass: the state of Para. Eighteen years of time series of climatic variables, PM2.5, AOD and health were analyzed for two Para municipalities located in regions with very different environmental and social characteristics, through an ecological study of epidemiological character. In general, the two places analyzed showed an increase in the hospitalization rate in the second semester of each year of the historical series, despite Santarem showing high numbers of these records throughout the year. The climate also played an important role in increasing the incidence of respiratory syndromes, because it makes the environment conducive to fire action, however, the results showed that years without significant climatic anomalies can also present high records of fires and PM2.5. When these relationships were analyzed in just one year and with a record of fires, a clearer combination between the investigated variables was found, with good statistical correlation, as well as a surprising and worrying increase in fires in the municipality of Santarem, even surpassing Maraba, a municipality that has always been ahead with the highest values of deforestation, fires and air pollution. Maraba perceives the effects of fires in advance, in general, two months before Santarem, and this situation is explained by the geographic location, degree of forest preservation, response to climatic fluctuations, industrial activity and public policy action. A sample taken from the time series showed that Maraba reaches, at the height of the dry season, attention and emergency levels for PM2.5, thus presenting low air quality. Santarem did not register alarming levels, but daily monitoring detected many days with levels above the permitted level, in accordance with the standards established by environmental legislation. The levels of pollution detected can increase the number of outcomes for respiratory diseases, overloading the state's public health system.
Acesso aberto (Open Access)
Afinidades geoquímicas entre sedimentos (solos) e vegetação (gramíneas e cultivares), além de cabelo de ribeirinhos, ao longo das praias de rios da bacia do Juruá, no estado do Acre e sua importância ambiental
(Universidade Federal do Pará, 2005-06-10) RÊGO, José de Arimatéia Rodrigues do; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
The State of the Acre is located in the southwestern extremity of the Brazilian Amazonia, in an area of 153.149 km2, with a low population density (3,66 inhabitants/km2). The studied area comprehends the basin of the Juruá river between the Feijó and Cruzeiro do Sul cities, including Tarauacá and Rodrigues Alves. In the basin the main rivers are: Juruá, Tarauacá, Envira, Muru and Moa. The same carry in sediments great amounts by traction and suspension from siltic- argillaceous rocks of the Solimões Formation and deposite in beaches formed along the rivers. In drought periods the beaches (point bars) are displayed in its meanders and benefit the riparian that use them to leisure and to short cycle agriculture. The beaches sometimes are used to cultivs of maize (Zea-Mays) and beans (Vigna unguiculata (1) Walp). These beaches also present a vegetation succession of canarana grass (Costus spicatus) and orvalho grass (Brachiaria decumbes). This study evaluates the high fertility of the beaches sediments (soils) and the geochemistry affinity between their sediments and the crops besides riparian hair and the environmental importance of this cycle. So the main rivers that constitute the Juruá basin, enclosing Feijó, Tarauacá, Cruzeiro do Sul and Rodrigues Alves cities were related. Nine stations were established along the rivers and samples of beach sediments, canarana grass leaves, orvalho grass leaves and seeds and beans leaves had been leaves were collected. Besides this, measurement of phisical-chemical parameters of the rivers waters were caried out. Human hair samples were collected in the cities. The sediments samples were analyzed by X-ray difraction (XRD) for mineral determination, are by chemical ICP-MS for characterization (major and trace elements). In attempt to verify the content of Major and Trace Elements, like Ca, Fe, K, Na, Ba, Zn, Mo, Co, Cr, Cu, Pb, Hg, As and Se and their sediment — (solil) — crops transference were camet the chemical compositions analyses were carried out with regal water plus MS-ICP and neutron activation. The studied beaches sediments in the cultivated areas excet the beach of Moa river are essentially fine-grained, ranging from fine sand to silt. And are formed by in decressent order quartz, feldspars clay minerals (smectite, illte and kaolinite) and feldspars. Chemical are constitute binaimes by SiO, (68,0 98,9 % in weight), following by significaty lower values, of Fe>03 (0,13 to 4,37 %), MgO (0,02 to 1,03 %), KO (0,16 to 1,94 %), CaO (0,02 to 1,05 %) and Na,0 (0,02 to 1,03 %) and AlOs, are more concentrated in the sediments of Envira, Tarauacá and Juruá rivers. These values compened chemical with that one of the PAAS and, the Upper Crust, are slightly impoverished in Al, Fe, Mg, K, Ti as well as slightly in Ca and Na, diluted certainly for the high contents of SiO2. In general, the rivers waters of the Juruá basin are dark-colored, as white waters type, due to inorganic material in suspension (suspensates) in high concentration. The criterion of suspensates and phisical-chemical parameters (pH, DO, TDS, temperature, resistivity, electric conductivity and salinity) delimit three geographic zones (sub-basins): a) Envira-Tarauacá, b) Juruá and c) Moa rivers. The first one presents the highest values of all the analyze phisical-chemical parameters, except resistivity, and the area coincides with the more fertile land area State of the Acre. Among the studied vegetables the canarana grass leaves revealed are richerest in K, S, Ca, Mg, P than orvalho grass leaves. Canarana and orvalho grass present chemical similarity in relation to K, P, S, Mg and Ca elements. Only canarana grass, collected in the sediments of the Juruá river tends to become richer in Ca and S. The chemical elements transference sediment (soil)-vegetable presents an absorption for vegetal of the K>P>Ca>P. This order presents the major values for vegetables collected in the sediments of Envira river, emphisizing the importance of Envira river with greater transference potential of macronutrients and being a probable pointer of its superior fertility in relation to the other rivers of Juruá basin. In the sediment-crop-human chain the cycle of Hg shows that in the beach sediments of the Juruá, Envira and Tarauacá rivers the average concentration of Hg (27 ppb) in the sediments below the background range (50 ppb) and in the plants is in according to normal considered range (< 500 ppb) for plants that grow in soils with low contents of Hg; the average contents of Hg in hair in Tarauacá, Cruzeiro do Sul, Rodrigues Alves and Feijó rivers is about 3992 ppb. The lower concentration (average 1680 ppb) was found in Feijó and the higher (6240 ppb) in Cruzeiro do Sul, being normal values and slightly impact indicators, not observed in the region. The slightly anomalous values of Hg in hair is not related to the crops, as well as to the sediments. For hunam other sources of Hg disponibilization must be evaluated as fish or domestic or wild animals meats. The beaches and abrupt declivities (banks) of the white water rivers of the central and western regions of Acre (Juruá basin) are really fertile, adequated to short cycle agriculture and its nutrients and other elements are completely assimilated by vegetables and crops. For the present study the chemistry of the sediments and crops, as well as of human hair, shows that the region does not present geochemistry anomaly of any considerable antropogenic impact.
Acesso aberto (Open Access)
Afinidades petrológicas e geocronologia U-Pb em zircão de ortognaisses do Complexo Gnáissico-Migmatítico Água Azul, Terreno Sapucaia, Província Carajás.
(Universidade Federal do Pará, 2024-10-09) PINTO, Eliziane de Souza; OLIVEIRA, Davis Carvalho de; http://lattes.cnpq.br/0294264745783506; https://orcid.org/0000-0001-7976-0472
The Água Azul do Norte area is part of the geological context of the Carajás Province, precisely in the Sapucaia Terrain, according to the recent tectonic compartmentalization proposals presented by the Granitoid Petrology Research Group (GPPG/UFPA). This region is formed by a mesoarchean orthognathic basement with TTG affinity (Água Azul GneissicMigmatitic Complex; 2.93 Ga) associated with late Mesoarchean intrusions with sanukitoid signatures (Água Azul and Água Limpa Granodiorites; 2.88-2.87 Ga), high-Ba-Sr sodic (Nova Canadá Granodiorite; 2.89-2.87 Ga) and high-K calc-alkaline (Boa Sorte Granite; 2.89- 2.85 Ga) signatures. The review of geological and petrographic data indicated that the TTG crust of Água Azul do Norte is compositionally heterogeneous and records strong evidence of progressive metamorphism and migmatization. Therefore, this work reclassifies this TTG basement as being formed by orthogneisses, which occasionally present variations to tonalitic to quartz dioritic compositions that resemble fragments of a more primitive, intensely deformed and gneissified crust. These varieties show compositional banding in an E-W direction, often disturbed by shear bands and drag folds. Considering the classification of migmatites, they have an orthognathic paleosome and leucosomes rich in Qz+Pl±Bt parallel to the banding (stromatic metatexite) and frequentely outlined by mafic aggregates (melanosome rich in biotite and hornblende). They form four compositional varieties: i) hornblende±biotite tonalitic orthogneiss (HBTnl), ii) clinopyroxene-hornblende tonalitic orthogneiss (CHTnl), iii) epidote-biotite orthogneiss quartz diorite (EBQzD) and iv) hornblende-biotite orthogneiss quartz diorite (HBQzD). They present a large proportion of mafic minerals (M'> 15%), especially biotite and hornblende, which can occur slightly stretched along the foliation plane. Plagioclase and secondary quartz are abundant and occur in the matrix or, in the case of plagioclase, as phenocrysts, while alkali-feldspar and primary quartz are practically insignificant. Whole rock geochemical analysis indicated that samples MED-120A (EBQzD) and MEP-53B (HBQzD) present moderately magnesian character, medium-K calcium-alkaline signature, relative depletion in K2O, MgO, Ba, Ni and Cr and enrichment in Na2O, Al2O3, TiO2, Fe2O3 and Zr, reflecting a certain affinity with traditional tonalite-trondhjemitic associations. The presence of many zircon crystals with igneous features preserved in these samples marks the crystallization age of the protolith at 3.06 Ga, suggesting that they are crustal fragments approximately 100 Ma older than the underlying crust (Água Azul Orthognathic Complex). MED-144 (HBTnl) exhibited a strongly magnesian character, high-K calcium-alkaline signature, high K2O/Na2O ratio and enrichment in MgO, Ba, Ni and Cr, very similar to the composition observed in sanukitoids. The U-Pb data obtained for this sample indicated a crystallization age of 2.92 Ga, similar to that observed in sanukitoids described in the Ourilândia do Norte region (Arraias Granodiorite). The other samples showed significant contents of compatible elements (e.g. Fe, Mg, Ni, Cr) and moderate contents of incompatible elements (e.g. K, Rb, Ba, Sr, Zr, Ti) and revealed an intermediate behavior between TTGs and granitoids enriched in Mg, as well as a strong affinity with the São Carlos Orthogneiss (2.93 Ga) described in the same terrain. Concordant U-Pb ages obtained for samples MED-95A (HBTnl) and EDC-28B (CHTnl) indicated acrystallization at 2.95-2.93 Ga contemporaneous with the emplacement of the Água Azul TTGs and the São Carlos Orthogneiss. The textural behavior of the quartz and mafic minerals indicates dynamic recrystallization mechanisms at intermediate to high temperatures (~500-650ºC), while the morphology observed in the migmatites (stromatic metatexitic and leucosomes with hydrated minerals) suggests that there was a low amount of melt produced and fluids participation in the partial melting process. Combined with the mineral paragenesis (Pl+Qz+Bt±Hbl±Ep), these factors point to a granitic protolith metamorphosed under amphibolite facies conditions, with the migmatization being strongly contemporaneous with the deformation and peak of the regional metamorphism described in the Carajás region (2.89 Ga; MED-95A).
Acesso aberto (Open Access)
As águas subterrâneas de Belém e adjacências: influência da Formação Pirabas e parâmetros físico-químicos para medidas de qualidade
(Universidade Federal do Pará, 1996-04-08) SAUMA FILHO, Michel; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
In the Metropolitan Region of Belém (PA) the water supply to the population comes from springs (physiographic area of Utinga) and from a network of positional tube wells, in general, in more remote urban areas or where pumping is precarious. This work evaluates the groundwater used in the Metropolitan Region of Belém, correlating data of physical, physical-chemical and chemical parameters, in an attempt to compose an understandable picture about the quality of these waters, and to verify the influence that they suffer from the geological units in which they are located. the aquifers that preserve them are located. To carry out the work, water samples were collected in two different seasonal periods: dry and rainy. After exhaustive consultation of the files of companies, institutions and researchers, 17 tubular wells were selected, 9 in Belém, 5 in Icoaraci, 2 in Mosqueiro and 1 in Ananindeua (Annex A). The most frequent turbidity indices were between 9 and 14 units (ppm of SiO2), but some wells showed higher values (33, 41 and 71 ppm of SiO2. Only in some cases, this turbidity can be immediately correlated with the silica content obtained by chemical analysis. The most frequent color measurements are in the range from zero to 7.5 U.C., with the zero index predominating. However, some wells showed a value above 100 U.C. and others, less frequent, with indices varying between 20 and 60 U.C. The pH and electrical conductivity were quite different parameters. Thus, the highest pH and electrical conductivity indices were verified in the aquifers of the Pirabas Formation. In these cases, the pH was around 6 .4 to 7.6 and conductivity between 231 and 362 µS/cm, with a discontinuity at 87.5 µS/cm, also attributed to a well associated with the aforementioned Formation. More acidic waters (pH below 6.38 and above of 4.01) are certainly attributed to the aquifers of the Barreiras and Post-Barreiras Group. The chemical constituents, notably the contents of Ca2+, Mg2+, Na+ and K+, are consistent with the interpretation of the numerical values of pH and electrical conductivity. Without exception, the concentrations of Ca2+ are higher than those of the other cations, establishing a decreasing order according to Ca2+> Mg2+> Na+>K+, with some inversion between Na+ and Mg2+. The highest concentrations of Ca2+ (soon followed by Mg2+) result from the dissolution of carbonates present in the Pirabas limestone. In fact, confirming this assertion, the concentrations of HCO-3 are also much higher than the concentrations of Cl- and SO2-4. It is to be expected, therefore, that the dissolution of Pirabas sediments produces higher concentrations of Ca2+ and HCO-3. The silica and iron contents also discriminate such waters. In general, higher silica contents correspond to greater depths, as would be expected, taking into account the action of chemical weathering on silicate minerals. As for iron, this constitutes a differentiating parameter of the waters of the Pirabas Formation, almost always at much lower levels than the corresponding values associated with the Barreiras and Post-Barreiras aquifers, with, however, exceptions, in which appreciable indices of iron related to Pirabas sediments. It should be noted that the Pirabas Formation appears in the Metropolitan Region of Belém almost always at depths greater than 100 m, although there are records of smaller depths, but these are apparently rarer situations, as is the case with well number 3. , on the University Campus, near the Guamá River, with a depth of 76 m, and the 94 m well of the Museu Paraense Emílio Goeldi, in the central area of the city (Annex A). The exhaustive consultation of the aforementioned archives of institutions, companies and researchers led to the realization that many tubular wells installed in the urban area use water associated with the Barreiras and Post-Barreiras aquifers, where the pH values are almost always, below 6 units, and electrical conductivity measurements rarely reach 100 µS/cm. Finally, it appears that there is a need for greater investments in order to increase the prospection and use of groundwater in the region, as these, in addition to dispensing with treatment prior to distribution, are still a source of resources, not dimensioned, but of great potential.
Acesso aberto (Open Access)
Alagamento e inundação urbana: modelo experimental de avaliação de risco
(Universidade Federal do Pará, 2010-03-18) SANTOS, Flávio Augusto Altieri dos; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
This study aimed to develop an experimental model for assessing risk of flooding and flood to Bethlehem, based on the model of digital terrain elevation, the runoff hydrograph and the peak flow of the main drainage channel of the river basin. We used GIS tools to systematize the vector data on the units occupied by buildings, roads and the axis of altimetric quotas to generate a digital terrain model. The development of the system was customized by programming language, aiming to facilitate and simplify the operation of the processing routines of the equations defined for the implementation of the hydrological model. The hydrologic model basin was subdivided into cells of 25m², and each one was given his share of high and calculated their runoff based on the percentage of impermebialização of each. The peak discharge channel was obtained on field trips at two different situations: during rainfall events of high intensity and one without the influence of rain. For these two conditions, it was also evaluated the influence of the tide of the Guamá River on the main channel of the basin. The consistency of the model was found from the sensitivity test performed for each variable used and validated based on data from some rainfall events that was checked by journalistic and photographic records obtained in the field. The results indicate that the applied hydrologic model, and the developed system are efficient and effective to be applied as a tool for risk assessment of flooding and flood.
Acesso aberto (Open Access)
Alteração hidrotermal e potencial metalogenético do vulcanoplutonismo paleoproterozoico da região de São Félix do Xingu (PA), Província Mineral de Carajás
(Universidade Federal do Pará, 2015-08-27) CRUZ, Raquel Souza; VILLAS, Raimundo Netuno Nobre; http://lattes.cnpq.br/1406458719432983
The region of Sao Felix do Xingu, south-central Pará, exposes a volcano-plutonic system exceptionally well preserved and grouped in the Sobreiro and Santa Rosa formations, in which hydrothermal alteration and mineralization associated were recognized. The Sobreiro Formation consists of lava facies flow of andesitic, basaltic andesite, and dacitic composition, according to the proportions or absence of clinopyroxene and/or amphibole phenocrysts. Volcaniclastic facies is genetically associated and is represented by mafic crystals tuff, lapilli-tuff, and massive polymictic breccia. Santa Rosa Formation is fissure-contolled and composed of lava flow facies and associated volcaniclastic facies of felsic crystal tuffs, ignimbrites, lapilli-tuff, and massive polymictic breccia. Part of this system is interpreted as ash-flow caldera partially eroded and developed in several stages. Conventional petrography, X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy show hydrothermal alteration paragenesis occurring in these rocks. In general, the alteration minerals develop subeuhedral anhedral crystals and replace magmatic minerals. The types of hydrothermal alteration identified are incipient the pervasive and are distinguished propylitic, sericitic, intermediate argillic, and potassic, which overlap, and fracture-controlled silicification associated with hematite and carbonate. Propylitic alteration, prevalent in Sobreiro Formation, presents both pervasive and fracture-controlled styles. The paragenesis consists of epidote + chlorite + carbonate + quartz + sericite + clinozoisite ± albite ± hematite ± pyrite, which is overlapped by pervasive potassic alteration or fracture-controlled, mainly represented by potassic feldspar + biotite ± hematite. Locally, fracture is filling with prehnite-pumpellyite association that suggests geothermal low-grade metamorphism conditions. The sericitic alteration is marked by the occurrence of mainly sericite + quartz + carbonate ± epidote ± chlorite ± muscovite. It is manifested mainly in mafic crystal tuff. However, the overlap of these types of changes is evidenced by relics of propylitic chlorite alteration and textures of rocks, partially obliterated, in which there were only pseudomorphs of sericitized plagioclase. In the Santa Rosa Formation the sericitic alteration is pervasive and characterized by the occurrence of sericite + quartz + carbonate. Also presents fracture-controlled, which is represented by sericite + quartz. It is the main type of change identified in this unit by assigning the whitish rocks. SEM data show that, associated with the sericitic alteration occur lead phosphate, gold, rutile, and barite. The potassic alteration is more subordinate, generally associated with granitic porphyry and locally to rhyolites. Paragenesis is given by microcline + biotite + chlorite + carbonate + sericite ± albite ± magnetite. The intermediate argillic alteration was recognized in rhyolites and possibly corresponds to the final stages of hydrothermal alteration. It is characterized by the presence of montmorillonite + illite + chlorite + sericite ± kaolinite ± halloysite ± quartz ± hematite, which were identified by infrared spectroscopy and XRD. It gives whitish to whitish pink to the rocks. The hydrothermal alteration types were mainly controlled by temperature, fluid composition, and fluid/rock ratios. They are compatible with thermal anomalies related to magma, and possible temperature decrease due to mixing and neutralization with meteoric water, similar to that described in low- and intermediate-sulfidation mineralization. Gold identification and compatible accessories phases provide important information for prospective studies in the region, especially for potential intermediate- and low-sulfidation epithermal deposits of precious metals (gold and silver) in volcano-plutonic systems with related ash flow calderas, as well the Au(Cu) and Mo porphyry-type deposits.
Acesso aberto (Open Access)
Alteração supergênica das rochas básicas do grupo Grão-Pará: implicações sobre a gênese do depósito de bauxita de N5 - Serra dos Carajás
(Universidade Federal do Pará, 1981-11-19) LEMOS, Vanda Porpino; VILLAS, Raimundo Netuno Nobre; http://lattes.cnpq.br/1406458719432983
The present study deals with the supergene alteration of the basic volcanic rocks of the Grão Pará Group and gathers evidences that support the N5 bauxite deposit (Carajás Sierra) to be an extreme product of this alteration. In the lack of a continuous profile, this hypothesis was tested with a composed profile using the subsurface information available for the contiguous N4 plateau where the whole weathered sequence could be observed. The bauxite-rich and lateritic horizons, only developed in N5, were then assumed to be a part of that sequence and taken as its more superficial levels. The basic volcanic rocks are of precambrian age and were classified as tholeiitic basalts compositionally similar to those of the calc-alkaline suites that occur in modern island ares (TiO2-Zr/P2O5 diagram). The primary mineral assembly is dominantly composed of labradorite and pigeonite-augite and has zircon, ilmenite and opaque minerals as the major accessory phases. Hydrothermal activity caused mineralogical changes in theses rocks producing chlorite, epidote, calcite, sericite, amphibole and quartz. Significant chemical and mineralogical changes were induced by the weathering in these rocks and could be evaluated to depths up to 140 m. The serbidecomposed material showed substantial losses of CaO, Na2O and FeO (this due to partial oxidation to Fe+3) and less important lasses of SiO2, MgO and K2O. In contraposition there was relative enrichment of Fe2O3, Al2O3, TiO2 and P2O5 besides major gains of H2O. This new chemical environment favored the formation of compatible stable phases represented, in order of abundance, by chlorite, smectite-chlorite, opaque minerals and quartz. The totally decomposed basalts revealed an aimost complete loss of alkalls, MgO and CaO, with SiO2 contents dimishing to values of approximately 40% of its initial quantities. This enhanced great relative gains of Fe2O3, Al2O3, TiO2 and P2O5 and H2O with respect to the previous alterations stage. The resulting mineral assembly turned out be dominated by kaolinite, goethite and titanium oxides, and secondarily by gibbsite and quartz. Determinations of Cr, Ni, Co and Zr were done for both the bas.alts and its weathered equivalents. Enrichment factors of the order of 1.5 to 5.0 generally progressive towards the surface indicate the greater or lesser mobility of these elements within the supergene environment. Cr, Ni and Co were retained by coprecitpitation with iron hidroxides while Zr was accounted for by the preservation of zircon as a residual mineral. The N5 bauxite deposit consists of a gibbsite-rich upper layer with an average thickness of 4.7 m and average chemical composition of 3-.13% SiO2, 2.3% TiO2, 47.0% Al2O3, 23.0% Fe2O3 and 24.0% volatiles. Mineralogically it is composed of gibbsite, kaolinite, titanium oxides and iron hidroxides (goethite). The subjacent layers show distinct chemical constitution but the mineral suites differ in the proportions rather than in the kinds of the phases present. Downwards it is observed 1) a lateritic crust as thick as 10 m, 2) a gibbsite-rich clay that do not exceed 35 m in thickness and 3) an argillaceous horizon of indefinite thickness. The lateritic crust has an average chemical composition of 3.6% SiO2, 2.0% TiO2, 28.0% Al2O3, 47.0% Fe2O3 and 19.0% volatiles, and a mineralogy dominated by hematite, kaolinite, iron hidroxides, titanium oxides and subordinate quantities of gibbsite. The gibbsite-rich clay has average proportions of 24.0%, 2.0%, 28.0%, 32.0% and 13.0.% for SiO2, TiO2, Al2O3, Fe2O3 and volatiles respectively while the argillaceous horizon shows average proportions of 47.0%, 1.5%, 20.0%, 22.0% and 7.5% for these same components in that order. The mineral assembly of these two last levels is dominated by kaolinite, gibbsite, titanium oxides and iron hydroxides although hematite appears only in the gibbsite-rich clay while goethite and quartz appear, only ,in, the argillacebus horizon. The identification of heavy minerals in samples of both the decomposed basalt and the bauxite material revealed the same suite consisting of ilmenite, zircon and tourmaline, the latter mineral being found in greater abundances in the bauxite. Boron determinations from samples of the various horizons of both sequentes (N4 and N5) indicated contente that varied from 70 to 100 ppm, justifying /the probable presence of tourmaline even in the rocks from which was not possible to separate heavy minerals. The integration of all these data allowed the interpretation of the N5 bauxite plateau as a residual deposit of the supergene alteration of the volcanic basic rocks of the Grão Pará. Group with basis on 1) the chemical and mineralogical identities between the two sequences, especially the decomposed basalt and the gibbsite-rich clay, 2) the chemical correspondente that suggests the argillaceous horizon to be an intermediate stage of alteration between the semidecomposed and the decomposed basalt, 3) the presence of gibbsite in the decomposed basalt suggesting a stage of evolution which, given enough time and the appropriate conditions, could produce a material progressively rich in alumina and 4) typical trace elements of basic rocks present in relatively high concentrations in the bauxite deposit and, taken the genetic link for granted, showing enrichment or impoverishment factors along a common trend from the unaltered basalt to the bauxite material. Special attention was paid to the lateritic crust that formed underlying the bauxite deposit. It has been interpreted as a result of the relativo mobility of Fe and Pd, under Eh-pH conditions that favored the descending movement of Fe and the fixation of in the upper horizons.