Navegando por Assunto "Metais pesados"

Agora exibindo 1 - 20 de 43

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Adsorção de molibdato em minerais de argilas naturais e modificadas com ácido sulfúrico, ácido húmico e uréia
(2013-03) PEREIRA, Patrícia Magalhães; LEMOS, Vanda Porpino; RODRIGUES, E.; FAIAL, Kelson do Carmo Freitas
Clay sediments from the municipalities Assis Brazil (Acre), were leached with solutions of sulfuric acid, humic acid and urea, to evaluate the retention capacity of molybdate in these materials and to investigate the feasibility of the adsorption processes at solid-solution interfaces. The materials were characterized from data of XRD, FTIR spectra, surface charge and chemical composition. The Langmuir isotherm models, Freundlich and Sips were used to fit the experimental data of adsorption. The minerals identified in the clay sediments were smectite, kaolinite, illite, quartz, albite, calcite and microclineo. The chemical modification leads amorphization of the modified sample with sulfuric acid and delamination along the plane 001 of the modified sample with urea. The settings defined by mathematical parameters (KL,Kf) of the adsorption isotherms, evaluation Ce vs. qe, pH vs. Qe, Qmax (sips) and Kd, indicated that the S10H15 sample is more efficient in the adsorption MoO42- ,with com qMax = 6.83 mg. L-1.
Acesso aberto (Open Access)
Aplicação de Al-PILC na adsorção de Cu2+, Ni2+e Co2+ utilizando modelos físico-químicos de adsorção
(2007) GUERRA, Denis de Jesus Lima; AIROLDI, Claudio; LEMOS, Vanda Porpino; ANGÉLICA, Rômulo Simões; VIANA, Rúbia Ribeiro
Smectite sample from the Serra de Maicuru area (Pará state, northern Brazil, Amazon region) were used for the pillaring process with Al13. Aluminum pillared clay (Al-PILC) was characterized by XRD, SEM and EDS. the textural analysis using nitrogen adsorption-desorption isotherms. The aim of this paper is to study in how Al-PILC adsorb heavy metals. The adsorption of Cu2+, Ni2+, Co2+ ions from aqueous solution in room temperature by Al-PILC have been carried out. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data, with the first model well adjusted with r = 0.999. The one-surface Langmuir equation provided the best fit to the data. The Freundlich equation presented limitations in rises concentrations, but acceptable values of parameters were obtained (Kf and n) with the use of the three models. The parameters were used to calculate the amount adsorbed Nf, a function constant Cs.
Acesso aberto (Open Access)
Avaliação ambiental dos recursos hídricos, solos e sedimentos na área de abrangência do depósito de resíduos sólidos do Aurá - Belém-PA
(Universidade Federal do Pará, 2002-03-27) PIRATOBA MORALES, Gundisalvo; FENZL, Norbert; http://lattes.cnpq.br/6834981018643186
With 1.754.099 inhabitants, the municipality of Belém produces roughly 1,200 tons per day of all kinds of waste, which are deposited in a landfill known as Lixão do Aurá, bordering the municipality of Ananindeua. During the past 11 years, this area has been accumulating approximately three million and two-hundred thousand tons of solid waste, transforming that place into a permanent local source of anthropogenic pollution, altering environmental conditions and resources around the whole area surrounding it. A Vertical Electrical Resistivity Sounding (VERS) procedure, conducted in the area before it was transformed into the landfill (1991), compared with the measures taken eight years later (1998), show that the land resistance has considerably dropped, with values in some cases — 109 times smaller than the original ones, thus indicating that the layers have been affected by the leach from waste decay. Fifteen profiles were conducted in the area, using the electrical imaging system, allowing us to confirm the (VERS) results, with evidences that the underground water has been affected by the infiltration and by the leachate vertical and horizontal movements. The hydro geological characteristics in the area show that the local predominant type of aquifer is of the free kind, locally confined, with hydraulic gradient of approximately 0.695%, effective porosity of 28%, permeability coefficient ranging from 1.1 x 10-3 to 0.9 x 10-4 cm/s, and underground flows running north/south towards the Guamá River, at approximately 14.79 m/year. A multivariate statistical analysis has shown that superficial water samples, collected simultaneously at three control points, during one tide cycle, regardless of the season, portray totaily different behaviors, indicating that superficial water resources are being affected by the superficial movement of leachate. With the concentration value figures for each of the leachate parameters (pH, conductivity, alkalinity, ammonia, total organic carbon, chloride, sodium, potassium, calcium, and magnesia), plus the flow of the Aurá River at the control point near the Guamá River, it is possible to estimate the quantity of pollutants that the solid waste landfill sends into the water system. During one tide cycle, in the dry season, the solid waste landfill deposits approximately 13,115 kg of chloride, 417 kg of ammonia, and 129,767 kg of salts in the local water system. For the underground waters, the multivariate statistics showed that the samples collected In the monitoring wells in the area show significant differences, indicating that the wells located downstream have been affected by the leachate. The presence of sand layers right in the area where solid waste is deposited allows for the vertical and horizontal movement of the different pollutants originated by the leachate. The heavy metais anaiyses, conducted under the sequential extraction methodology, showed percentages in the geochemical phases potentially bio-available in the studied soil and sediment samples. In the soil samples, the potentially bio-available fraction (replace, reduce, and organic geochemistry phases) contained an average of 32% of the total Cadmium (Cd), 11.8% of the total Chromium (Cr), 23% of the total Copper (Cu), 12.32% of the total Nickel (Ni), 43.1% of the total Lead (Pb), and 31.01% of the total Zinc. The potentially bio-available phases percentage in the sediments of the area was greater than the ones found in the soil samples. In these sediments, the quantity of heavy metais in the potentially bio-available fraction, shown higher values during the dry season than during the rainy season; for instance, 33% of the total Cd measured during the rainy season increased to 37% in the dry season; Pb increased from 61 to 70%; Zn, from 51 to 54%, among others. The metais analyzed by total attack in the soil samples, compared with the sandstone backgrounds, indicate that the Fe (3.1%), Cu (18.5 ppm), Ni (10.1 ppm), Pb (69.5 ppm), Cr (76 ppm), and Cd (>1 ppm) are above normal standards. In the case of sediment samples, the EPA background values (total concentration) would be moderately polluted by Cr (average 64.6 ppm) and heavily polluted by Fe (3.8%) and Mn (600 ppm). These results show that the sediments were not polluted by Pb and Zn. Considering the potentially bio-available phase and using the tool provided by a Geographic Information System (GIS), we can say that, during the rainy season, the sediment samples were not polluted by Cr (potentially bio-available fraction smaller than 20% of the total) were highly polluted by Pb and Zn (PBD higher than 50%), and moderately polluted by Cu, Ni, and Cd (PBD between 20 and 50%).
Acesso aberto (Open Access)
Avaliação atual da qualidade das águas dos lagos Bolonha e Água Preta, situados na área fisiográfica do Utinga (Belém-PA).
(Universidade Federal do Pará, 1992-12-17) RIBEIRO, Hebe Morganne Campos; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
Acesso aberto (Open Access)
Avaliação da exposição ao mercúrio e seus compostos sobre o desenvolvimento neuropsicomotor em crianças de Porto Velho-RO
(Universidade Federal do Pará, 2002-06-27) MARQUES, Rejane Corrêa; AMORIM, Marúcia Irena Medeiros de; http://lattes.cnpq.br/6969908284845675
A cohort of 100 births was generated during november and december of 2000 in Porto Velho city. Mothers and her newborns had been examined to verify total mercury levels (TML) at the birth, and the course of posnatal exposure on development and growth of infants during the first semester of their extrauterine life. To evaluation of prenatal exposure TML at the birth in samples of maternal and newborns hair, placenta, umbilical coord, and maternal blood had been analyzed. The newborns underwent physical and clinical examination. Mothers answered a questionnare that included important infonnations about risk factors to mercury accumulation or that could affect the development and growth of her childrens. At six months of age, 86 of the infants underwent detailed phisical and neurobehavioral examination, to evaluate the postnatal exposure. Besides a new sample of infants hair had been analyzed to verify TML. All data had been analyzed, compared, and underwent statistical evaluation. 23 infants (26%) showed neurological developmental disturbance at six months of age. This had been correlated with TML in children hair as at birth as at 6 months of age. A statistically significant correlation was observed between the head circumference and TML' s in the several analyzed samples.
Acesso aberto (Open Access)
Avaliação da presença de metais pesados na água potável fornecida à população urbana de Altamira e o seu possível impacto epidemiológico sobre doenças crônicas renais
(Universidade Federal do Pará, 2024-04-30) STORCH, Wesley; FAIAL, Kleber R. Freitas; http://lattes.cnpq.br/0166366420811929; HTTPS://ORCID.ORG/0000-0002-8575-1262; PEREIRA, Adenilson Leão; http://lattes.cnpq.br/3184636120604556
The Xingu River is crucial for potable water supply in Altamira, but it faces risks of heavy metal pollution, especially mercury, due to illegal mining and UHBM activities. Mercury can bioaccumulate in humans and be associated with an increased risk of hypertension and kidney diseases. This study evaluated the presence of heavy metals in Altamira's drinking water and outlined the epidemiological profile of chronic kidney disease (CKD) in Altamira and the Xingu region. Concentrations of Al, As, Cr, Cd, Pb, Fe, and Hg were measured in 24 water samples collected in July 2022, using ICP/MS by the Evandro Chagas Institute, compared to Brazilian legislation and WHO limits. Mortality data from CKD, diabetes mellitus (DM), and systemic arterial hypertension (SAH) from 2000 to 2020 were analyzed using public data from DATASUS. Additionally, medical records of CKD patients treated at HRPT from 2007 to 2023 were analyzed. The concentrations of metals in the analyzed water samples were within established limits, except for aluminum (Al), which was elevated in two water samples. Mortality data obtained from DATASUS between 2000 and 2020 showed a significant increase in mortality due to SAH in Altamira (R²=0.80), while mortality from CKD (R²=0.30) and DM (R²=0.31) had a smaller impact on the mortality rate during the studied period. Considering the medical records of CKD patients treated at HRPT, it was identified that between 2007 and 2023, 174 CKD patients treated at HRPT were from Altamira, with 64.4% men and 35.6% women. Regarding age, 48.85% were over 60 years old, and 36.78% were between 41 and 60 years old. The main comorbidity associated with CKD was SAH (56.90%), followed by the association of SAH and DM (36.94%). Altamira presented an average prevalence of 8.99 cases per 100,000 inhabitants and an average incidence of 10.24 new cases per year of CKD during the analyzed period. In the Xingu region, 403 CKD cases were identified, predominantly in men (61.5%) with an average age of 60 years. The main comorbidity associated with CKD was SAH (49.88%), followed by the association of SAH and DM (37.47%). The average prevalence of CKD in the region was 6.97 cases per 100,000 inhabitants, with an average incidence of 23.70 new cases per year of CKD during the analyzed period. The levels of metals in the analyzed water samples are within the limits recommended by Brazilian legislation and WHO. The high prevalence of CKD in Altamira and the Xingu region raises concerns about public health impacts. Historical mercury contamination may be related to the high mortality from SAH and the prevalence of CKD associated with SAH. These results emphasize the need for continuous monitoring of water quality and public policies to mitigate the impacts of CKD in the region.
Acesso aberto (Open Access)
Avaliação de risco ambiental por contaminação metálica e material orgânico em sedimentos da bacia do Rio Aurá, Região Metropolitana de Belém - PA
(Instituto Nacional de Pesquisas da Amazônia, 2013-03) SIQUEIRA, Gilmar Wanzeller; APRILE, Fábio Marques
The Aurá River basin is situated in the Belém Metropolitan region, between the municipalities of Belém and Ananindeua, where the rate of population growth has increased without any social and environmental control. The region is intensely exploited and the more frequent environmental problems are deforestation, erosion, flooding, water pollution and contamination, especially by heavy metals and organic compounds (OC). Geochemistry behavior (Al, Fe, Mn, Cr, Ni and Cu) and OC levels were determined in the 30 sampling sites between 2008 and 2010 in the bottom sediments of the river. There is an uncontrolled sanitary landfill situated at the north of the Aurá River responsible, in part, by the metallic contamination of the sediments. The environmental stress is classic in the region, and it has resulted from anthropic activities, which has transported unconsolidated material associated to metals to the Aurá. The variables studied were classified on the transport mechanisms and sources (allochthonous and/or autochthonous). The results showed that the main contribution of ions Al and Fe was the sanitary landfill; Mn and Ni was the adjacent soils; Cr was modified (III/VI) by the allobiochemistry, and Cu by bio-induced processes.
Acesso aberto (Open Access)
Avaliação geoquímica da ocorrência de metais pesados selecionados em sedimentais pelíticos da plataforma continental do Amazonas no trecho entre a foz do rio Pará e o cabo Orange
(Universidade Federal do Pará, 2003-04-10) LIMA, Edgar Alexandre Reis de; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
Acesso aberto (Open Access)
Caracterização da assinatura isotópica de Pb atual e da concentração de metais pesados em sedimentos de fundo da foz do rio Guamá e da Baía do Guajará (Belém - Pará)
(Universidade Federal do Pará, 2007-11-09) NASCIMENTO, Suziane Magalhães do; LAFON, Jean Michel; http://lattes.cnpq.br/4507815620234645
The city of Belem launches a significant amount of domestic pollutants in natura and industrial effluents in the Guama river and the Guajara bay. Previous studies suggest that the bottom sediments deposited in the edges of the river and the bay have its chemical composition influenced by these anthropogenic inputs. The aim of this work is to characterize the Pb isotopic signature, associated to the study of the distribution of the concentration of Pb and other heavy metals (Cu, Cr and Ni) in bottom sediments from the hydrographic system of Belem (Guama river and Guajara bay), in order to evaluate the regional natural variations and to evidence possible anthropogenic contributions from the industrial and urban activities of the city of Belem. Thirty three georeferenced samples of bottom sediments from the Guama river and from the Guajara bay were collected, using a Petersen grab, with capacity to sample the first 10 cm of muddy sediments. Fourteen samples came from the left edge of the Guama river, including the Cumbu and Great islands, until it flow into the bay and nine samples from the right edge, at the city riverside. Nine samples of bottom sediments were also collected from the Guajara bay, beside eight samples from the islands (Jaguar, Jutuba, Jararaca and Mirin) and one from the riverside of Belem for the determination of heavy metal contents and Pb isotopic composition. At the laboratory, samples were dried in an oven (50°C), disaggregated in a agate mortar and sieved down to 63μm, for the separation of the fine fraction (silt + clay). The mineralogical composition of the fine fraction was determined by X-rays diffraction. The total and partial heavy metals concentrations were determined, respectively, by ICP-MS at commercial laboratory (Acme Ltda), and by ICP-OES at the Toxicological Laboratory of the Instituto Evandro Chagas, Belem. The determination of the Pb isotopic compositions was carried out on samples previously leached using HNO3 at the Para-Iso Laboratory of the Instituto de Geociencas - UFPA, and using a mixture HNO3 + HCl at the Geochronological Laboratory of the Centro de Pesquisas Geocronologicas - USP. The Pb separation and purification were carried out by ionic exchange chromatography. The Pb isotopic compositions have been determined by TIMS on a monocollector mass spectrometer VG Isomass 54E with, at the laboratory of UFPA and on a multicollector mass spectrometer VG354 at the laboratory of the USP. The results indicate that the mineralogical composition of the fine fraction of the sediments includes smectite, illite and Kaolinite. Chemical analyses of heavy metals furnished the following total and partial contents for the samples from the Guama river right edge: PbTotal (11-23 mg.Kg-1); PbPartial (9-18 mg.Kg-1); 10 CrTotal (26-69 mg.kg-1); CrPartial (11-23 mg.kg-1); NiTotal (7-29 mg.Kg-1); NiPartial (6-26 mg.Kg-1); CuTotal (7-23 mg.Kg-1); CuPartial (6-17 mg.Kg-1). For the samples from the left edge of the river, the following total and partial concentrations were obtained: PbTotal (16-20 mg.Kg-1), Pbpartial (13–19 mg.Kg-1); CrTotal (34-56 mg.kg-1), Crpartial (16-26 mg.kg-1); NiTotal (12-21 mg.Kg-1), Nipartial (12-16 mg.Kg-1), Cutotal (9-14 mg.Kg-1) and Cupartial (7-12 mg.Kg-1). The sediments from both edges of the Guama river similarly display a slight decrease of heavy metal contents downstream, in the direction of the bay. However, the sediments at south of the left edge islands display an increase of contents in the same direction. Variation in the dynamic of aquatic system of the Guama river by combined effect of currents and tides would probably account for such an opposite behavior. For the sediments from the right edge, significant variations of the metals contents were locally identified and are considered to be due to the confluence of the Aura tributary, which provokes local disturbs in the hydrodynamic of Guama river as well as a redistribution of the metals along the right edge of the river at a local scale. Physical-chemical conditions of the Aura water are probably modified by the effects of the Belem waste deposit, located on the edge of the river, by increasing of the metals solubility that may account for lower heavy metal contents of the bottom sediments from the Aura river up to the confluence with the Guama river. Consequently, the Aura river will not provide any significant input of heavy metals in the Guama river. Correlation diagrams display a good correlation between heavy metals and the organic matter and excellent correlations with Al, Mg and the Fe (r = 0.95-0.99) for the samples of the right edge of the Guama river, indicating that the heavy metals are associated to the organic matter, adsorbed by the clay-minerals (smectite, illite and Kaolinite) and, probably, associated to iron oxy-hydroxides, though they have not identified. Samples of the left edge did not provide any correlation of Pb and Cr with organic matter (r = 0.24 and 0.40), however excellent correlations were identified with Al and Fe (r = 0.94-0.97). Cu and Ni are poorly correlated with organic matter (r = 0.59 and 0.72) while the correlations with Al, Mg and Fe are good (r = 0.74-0.89). Therefore, clayminerals and, possibly, iron oxy-hydroxides prevail for heavy metals contents. The sediments of both edges of the Guama river have, respectively, total concentrations of Pb (23 and 20 mg Kg-1) and Cu (23 and 14 mg Kg-1) lower than the 35 mg Kg-1 (Pb) e 36 mg Kg-1 (Cr) values of TEL (Threshold effect level), established by the NOAA-EPA as a guide of quality of sediments and that defines the level below of which adverse biological effects will rarely occur. Then, sediments of the Guama river, even so they are in contact with domestic pollutants, do not represent any 11 risk, at the moment, for the aquatic ecosystem, at least regarding to Pb and Cu. The total concentrations of Cr (69 and 53 mg Kg-1) and Ni (26 and 18 mg kg-1), for the sediments of the right and left edges, respectively, are higher than or equal to the respective TEL values of 37 and 18 mg kg-1 for these metals and may constitute a risk for aquatic organisms of the Guama river. However, such Cr and Ni concentrations come probably from natural sources without any significant anthropic influences. The homogeneous isotopic signature of the sediments of the Guama river, together with the low Pb concentrations indicate a geogenic origin for this metal and allow to establish a value for the regional "background" of Pb concentration around 18-23 mg Kg-1. They also allow considering an isotopic signature of 1.200-1.194 for the 206Pb/207Pb ratios of Pb from natural sources, reinforcing the values previously proposed by Moura et al. (2004). The lower contents of Pb found in some samples from the right edge of the Guama river (11-13 mg Kg-1), associated to slightly anthropogenic isotopic signature (1.186 < 206Pb/207Pb < 1.193) are interpreted as a result of the influence of the Aura tributary on the sediments of the Guama river. The significant increase of Pb contents in the stream sediments of the Guajara bay is an indicator of possible future biological risks in the hydrographic system of Belem. The well established negative correlation between Pb concentrations (28-46 mg Kg-1) and 206Pb/207Pb isotopic ratios (1.172 < 206Pb/207Pb < 1.188), discards the possibility that the increase of Pb contents in the Guajara bay to be of geogenic origin and that the difference in concentration with the Guama river to be resulted only of distinct hydrodynamic processes.
Acesso aberto (Open Access)
Caracterização geoquímica de sedimentos de fundo da orla de Belém-PA
(Universidade Federal do Pará, 2001-09-14) PEREIRA, Kátia Regina de Brito; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
Acesso aberto (Open Access)
Caracterização geoquímica de sedimentos de fundo nas proximidades do distrito de Icoaraci - PA
(Universidade Federal do Pará, 2002-08-30) CARVALHO, Zilma Lima de; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
The Guajará Bay is the main water body that receives sewage from Belém's official network, receiving a daily volume of 18,294 m3/day, which is discharged in natura from the Una channel. This work aims to evaluate the influence of the release of this sewage on the quality of the sediments on the edge of Guajará Bay. For the purpose of comparison, two areas were chosen: one more impacted, located between the Una channel and the district of Icoaraci (Area 1) and another, less affected by the release of sewage, located near the island of Cumbu (Area 2). Sediments were collected at 18 points, 12 in Area 1 and 6 in Area 2. Mineralogical compositions were determined by X-ray diffraction and the concentration of metals in the total sample and in the soluble fraction was studied. The following metals: Cu, Cr, Ni, Pb, Zn, Mn and Fe. Concentrations were determined by atomic absorption spectrometry. The results show that the studied sediments are clayey and constituted mainly by kaolinite, illite and smectite. In Area 1, they present an average of 2.6% by weight of organic matter, with average concentrations of carbon and organic nitrogen of 1.51% and 0.08%, respectively. The concentration of total phosphorus shows an average of 216 mg/kg and as the sampled points move away from the Val de Cans channel, it shows a strong decrease (308 mg/kg to 132 mg/kg). The metals in the total fraction showed the following concentrations: Cu (16 mg/kg), Cr (66 mg/kg), Ni (24 mg/kg), Pb (59 mg/kg), Zn (70 mg/kg) , Mn (531 mg/kg) and Fe (37,181 mg/kg). Regarding the remobilizable fraction, the percentages observed were as follows: Cu (50%), Cr (15%), Ni (17%), Pb (51%), Zn (71%), Mn (83%), and Fe (47%). In Area 2, the average concentration of organic carbon was 0.43% by weight and that of organic nitrogen was 0.1% by weight. Organic matter reached a value of 0.74% by weight and organic phosphorus 495 mg/kg. Regarding metals, the average concentration observed was: Cu (13 mg/kg), Cr (36 mg/kg), Ni (35 mg/kg), Pb (55 mg/kg), Zn (33 mg/kg), Mn (214 mg/kg) and Fe (17,029 mg/kg). In the rewoundable fraction, the metals presented the following percentage in relation to the total content: Cu (41%), Cr (12%), Ni (32%), Pb (32%), Zn (73%), Mn (67 %) and Fe (70%). The concentrations of metals found in Area 2 were lower than those observed in Area 1, with the exception of phosphorus. The results confirm the strong anthropogenic influence on the quality of sediments in the Guajará estuary.
Acesso aberto (Open Access)
Comportamento de metais pesados e nutrientes nos sedimentos de fundo da Baía do Guajará e Baía do Marajó
(Universidade Federal do Pará, 2010-01-28) HOLANDA, Nielton de Souza; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
Human activities influence the physical and chemical characteristics of water, sediments and organisms in aquatic environments located in industrialized areas and high population density. With the increasing use of estuaries as a reservoir for a large amount of waste, coastal and estuarine ecosystems are gradually being subject to significant impacts. The bottom sediments play an important role in the investigation of these impacts since it has the ability to retain chemical species and inorganic. The objective of this research is to study the geochemical behavior of metals in the bottom sediment of the Bay of Guajará, Guama River and the Bay of Marajo. The two regions were chosen for their opposite characteristics: a Guajará Bay Area (1) under strong anthropogenic influence and Marajó Bay Area (2) considered the reference. We collected 83 points in Area 1 and 60 points in Area 2. Determined chemical concentrations of the following metals: Ba, Cr, Cu, Fe, Pb, Ni, V and Zn, and also the levels of nitrogen, carbon, organic matter, total phosphorus and phosphorus bound to organic compounds. Area 1 shows the average content of nitrogen of 0,08 %, mean levels of carbon and organic matter from 1,51 % and 2,60 %, respectively. The concentration of phosphorus and phosphorus bound to organic compounds 307 mg / kg and 126 mg / kg, respectively. The concentration of metals showed the following values: Ba (529 mg / kg), Cr (91 mg / kg), Cu (17 mg / kg) , Fe (6,82 %), Ni (32 mg / kg), Pb (27mg / kg), V (120 mg / kg) and Zn (69 mg / kg). Area 2 shows the average content of organic matter 1.70 % of carbon and nitrogen 0,98 % and 0,08 % respectively. The concentration of phosphorus and phosphorus bound to organic compounds 193 mg / kg and 7 mg / kg, respectively. The concentration of metals showed the following values: Ba (596 mg / kg), Cr (102 mg / kg), Cu (21 mg / kg) , Fe (8,31 %), Ni (40 mg / kg), Pb (28 mg / kg), V (141 mg / kg) and Zn (85 mg / kg). The carbon and phosphorus (0,98 %, 193 mg / kg), respectively found in area 2 were lower than those found in area 1 (0,51 %, 307 mg / kg) and demonstrate the influence of effluents that are released in the estuary Guajarino. In both areas there is the same downward trend in levels: Fe2O3> Ba> V> Cr> Zn> Ni> Pb> Cu. In area 1 were found higher metal alone while in area 2, with the major averages, the distribution is homogeneous, two areas in the metals has a slight tendency to concentrate where there is a higher content of organic matter.
Acesso aberto (Open Access)
Composição mineral da cana-de-açúcar in natura hidrolisada com cal virgem (CaO)
(Universidade Federal do Pará, 2014-12) DOMINGUES, Felipe Nogueira; OLIVEIRA, Mauro Dal Secco de; MOTA, Diego Azevedo; OLIVEIRA, Raimundo Parente de; SANTOS, Juliana dos; MIRANDA, Augusto Sousa; GODOY, Bruno Spacek
The aim of this study was to evaluate the mineral composition of “in natura” sugarcane hydrolyzed with increasing doses of quicklime and different periods of exposure to air. The levels of quicklime (CaO) used were 0.0 (control); 0.5; 1.0; 1.5 to 2.0% based on natural matter of cane and the time of exposure to air at 0; 24; 48; 72 and 96 hours. The mineral composition was assessed through the concentrations of calcium (Ca), phosphorus (P), potassium (K), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), chromium (Cr), lead (Pb) and cadmium (Cd). We used a completely randomized design. Data were analyzed using analysis of variance with repeated measures for comparison of means by Tukey test at 5% probability was used. The Ca concentration changes (P<0,05) caused a modification of the Ca:P ratio in the hydrolyzed sugarcane that reached 36.46:1 at the highest dose of lime (2.0%). The levels of P, K, Mg, Zn and Cu decreased with increasing levels of quicklime (P<0,05). Regarding to the period of exposure to air, there was an increase in the concentration of K, Mg, and Mn (P<0,05). The treatment of sugarcane with microprocessed quicklime (CaO) increases the Ca content of the forage. Pb is present in the quicklime but in a concentration well below the toxic concentration for ruminants.
Acesso aberto (Open Access)
Contaminação ambiental por mercúrio no distrito mineral de Nambija - Amazônia do Equador
(Universidade Federal do Pará, 2000-08-08) RAMIREZ REQUELME, Marlis Elena; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Acesso aberto (Open Access)
Contaminação no lago Xolotlán causada pelos despejos vertidos pela área metropolitana da cidade de Manágua, Nicarágua
(Universidade Federal do Pará, 1995-05-25) ALBUQUERQUE ESPINOZA, Noemi Marlene; FENZL, Norbert; http://lattes.cnpq.br/6834981018643186
Lake Xolotlán, the smaller of the two large lakes that occupy the Nicaraguan Depression, has been polluted by the metropolitan area of the city of Managuá since 1928, when it began to be used as a receiving body for the city's sewage. It currently also receives wastewater from the main industries in Nicaragua (located in Managua); sediments, garbage, high content of nutrients and organic pollutants from the drainage basin and the water that percolates from the main dump in the city of Managua (Lixão Acahualinca). To determine the levels of contamination by chromium, copper, arsenic, cadmium, mercury and lead on the southern coast of Lake Xolotlán, two sampling campaigns were carried out in six profiles with a north direction, starting from the discharge points of three sanitary sewage collectors, an industrial wastewater effluent, a rainwater drainage channel and in front of a "sanitary" landfill. In the first campaign, sampling was carried out up to a distance of 1000 meters from the lake shore and in the second, up to 500 meters. Water and sediment samples were collected for the analysis of trace elements and water samples for the determination of physical and physical-chemical variables. A third sampling campaign was carried out on two profiles to determine the concentrations of ƩDDT and toxaphene in sediments from Lake Xolotlán. For the determination of trace elements, the atomic absorption spectrometry method was used. ƩDDT and toxaphene were determined by the gas chromatography method. In the analysis of physical and physical-chemical variables, descriptive methods by APHA (1992) were used. The concentrations of chromium, copper, arsenic and cadmium in water were lower than the limits established by the National Council for the Environment (CONAMA) of Brazil in 1987 for brackish water intended for primary contact recreation, the protection of aquatic communities and the creation of species. intended for human consumption. Lead was exactly at the limit established by CONAMA for this pollutant (10ppb) at the point of discharge of the influent sampled from industrial wastewater in the first sampling. Mercury concentrations in water were high throughout the wastewater effluent profile, ranging from 0.6 to 0.1 ppb in both samples. In sediments from the coast of Lake Xolotlán, chromium was found at an average concentration of 15.1 µg/g and its distribution in most profiles indicates contamination by point sources, similarly to what occurs with copper (57 - 28 µg/g) and arsenic (1.3 - 11.2 µg/g). Cadmium contamination (0.7 - 4.7 µg/g) is a product of volcanic activity. Sediments sampled at the point of discharge of the sampled wastewater show a strong mercury contamination (57.6 µg/g), which decreases with distance. In turn, lead contamination (average concentration of 36.8 µg/g) is widespread throughout the study area and, with the exception of one profile, its spatial distribution indicates contamination by non-point sources. Toxaphene was only detected at the industrial wastewater discharge point, but the concentration was high (10 ppm). The distribution of ƩDDT suggests contamination by an unidentified point source. The results of the analysis of the physicochemical variables demonstrate that the volcanic activity is contributing with high values of Ph, solids, boron, fluorides and higher ion concentrations. The significant decrease in the concentration of nutrients and the chemical and biochemical oxygen demands, with the distance from the point contamination sources, reveal that Lake Xolotlán has a high stabilization capacity.
Acesso aberto (Open Access)
Desorption of heavy metals from ion exchange resin with water and carbon dioxide
(2006-06) SILVA, Denilson Luz da; BRUNNER, Gerd
Adsorption and regeneration of ion exchange resins were studied using a subcritical solution of a CO2-H2O mixture and a fixed bed column. The commercial Amberlite IRC-50/IRC-86 cation exchange resins and Amberlite IRA-67 anion exchange resin were tested for heavy metals (Pb, Cu, Cd) adsorption from a solution with different initial metal concentrations at different temperatures. After adsorption, the loaded resins were regenerated with water and carbon dioxide at different temperatures and a pressure of 25 MPa. The efficiency of the IRC-50 resin was lower than that of the IRC-86 resin for the adsorption of metals like Cd, Cu and Pb. Results obtained for desorption of these metals indicated that the process could be used for Cd and in principle for Cu. Sorption of metal ions depended strongly on feed concentration. Mathematical modeling of the metal desorption process was carried out successfully as an extraction process. For this purpose, the VTII Model, which is applied to extraction from solids using supercritical solvents, was used in this work.
Acesso aberto (Open Access)
Determinação espectrofotométrica do arsênio em cabelo usando o método do dietilditiocarbamato de prata (SDDC) e trietanolamina/CHCl3 como solvente
(2002) PEREIRA, Simone de Fátima Pinheiro; FERREIRA, Sérgio Luis Costa; COSTA, Antonio Celso Spínola; SARAIVA, Augusto Cesar Fonseca; SILVA, Antonia Kelen Frota
The silver diethyldithiocarbamate (SDDC) method, has been employed for the determination of arsenic in different materials. The disagreeable odor of the pyridine, the lower stability and reproducibility of the complex are justifications for many works related to the alternatives of the method. The SDDC/pyridine system was substituted for system using triethanolamine 5% v/v in chloroform with many advantages. The method was used for arsenic determination in hair samples with good recovery. Many kinds of digestions was studied.
Acesso aberto (Open Access)
Dinâmica da distribuição dos poluentes metálicos e orgânicos nos sedimentos de fundo dos canais de drenagem de Belém, Pa
(Universidade Federal do Pará, 1995-10-17) NASCIMENTO, Fernanda Souza do; FENZL, Norbert; http://lattes.cnpq.br/6834981018643186
Acesso aberto (Open Access)
Distribuição de metais pesados e hidrocarbonetos poliaromáticos em sedimentos de fundo dos rios Magdalena e Bogotá (Colômbia).
(Universidade Federal do Pará, 1997-09-08) PIRATOBA MORALES, Gundisalvo; FENZL, Norbert; http://lattes.cnpq.br/6834981018643186
Acesso aberto (Open Access)
Distribuição de metais pesados e isótopos de Pb em sedimentos do rio Amapari, setor de Pedra Branca do Amapari – Porto Grande, Amapá
(Universidade Federal do Pará, 2011-03-18) SILVA, Danúbia Tavares da; LAFON, Jean Michel; http://lattes.cnpq.br/4507815620234645
This work consists of a geochemical study of heavy metals and Pb isotopic signature of sediments from the hydrographic basin of the Amapari river, which is the main affluent of the right edge of the Araguari river, in the central region of Amapá State. The study is more precisely located in a part of the river, close to the Serra do Navio area, between the cities of Pedra Branca do Amapari and Porto Grande. The region hosts the larger mining district of Amapá, including two important gold and iron mines at the Serra do Navio. The aim of this work is to investigate the distribution of heavy metals and other metals like Al, Fe, Th and U, together with the determination of Pb isotopic composition of recent sediments that are sediments deposited at the superior edge of the river during inundation events (overbank sediments), sampled along the Amapari river and tributaries, in order to distinguish the natural contributions from the main geological units and a possible contribution of mining activities. The sampling strategy depended on two factors: (1) the occurrence of adequate outcrops and (2) the accessibility. The sediments, collected at 25 sampling points in November, 2007, include a set of samples from the Amapari river and three sets of samples collected in tributary of the right edge (Cachorrinho river and Cupixi river) and left edge (Cupixizinho river). In all the samples, granulometric, mineralogical, chemical and isotopic analyses were performed. The granulometric analyses were effectuated in order to determine the proportions of fine material (silt + clay) and clay. The mineralogical composition was determined by Xrays Diffractometry using a X-rays diffractometer with cobalt anode tube. The determination of major end trace elements contents has been carried out at a commercial laboratory (ACME Analytic Laboratory) by ICP-EOS and ICP–MS after four acids dissolution (HF + HCl + HClO4 + HNO3) in 8 whole samples and 22 samples of the fine fraction of the sediments. The elements of major interest were: Al, Fe, Pb, Mn, Cu, Zn, Ni, As, Cd, Cr, Th e U. For the isotopic analyses, the samples suffered total digestion with HF and HNO3+HCl (20 samples) and acid leaching with HNO3 (5 samples). The Pb separation and purification were achieved by ionic exchange chromatography (1x8 DOWEX resin). The Pb isotopic compositions were determined in static mode with a multi-collector thermal ionisation mass spectrometer Finnigan MAT262 at the Pará-Iso Laboratory of the IG-UFPA. The geochemical results indicate that all heavy metals behaved similarly and are enriched in the same samples, indicating that the sediments suffer the same processes of enrichment for all investigated heavy metals, excepting cadmium that displayed a different trend. No relationship between granulometry and heavy metals content was pointed out. Thus, the proportion of clays presents in the sediments does not appear to have been preponderant for heavy metals concentrations, at the contrary of that commonly occur in bottom sediments. Not significant variation of mineralogical composition has been observed between the fine fraction and the fraction superior to 62μm that account for the similarity of the chemical compositions between those fractions. In both granulometric fractions, the same main paragenesis composed by quartz, kaolinite, gibbsite and muscovite was identified. Other minerals were recognized in some of the samples (anatase, rutile, microline, etc.), which probably belong to the primary paragenesis. The presence of these minerals does not have influence on the heavy metals concentrations. The heavy metals contents furnished a better correlation with Fe than with Al contents although Fe-minerals were not been identified in the samples. The Pb isotopic compositions displayed significant variations and linear rend that permitted to construct isochrons in the 207Pb/204Pb vs. 206Pb/204Pb diagram, which defined Paleoproterozoic ages around 2,0 Ga, (Amapari river: 1964 ± 88 Ma, mswd = 1,6), indicating that the sediments came essentially from the Paleoproterozoic supracrustal units (metassedimentary and mafic rocks) and associated granitoids. Despite its extensive exposition in the area, the Archean basement does not significantly contribute as a source of the sediments. The concentrations of metals display strong variations according to the geographical location but they are randomly distributed along the Amapari river, indicating that homogenization does not occurred and that the sediments reflect the difference in the source rocks. Therefore the processes which account for that geochemical distribution are probably naturals as no was evidenced no correlation has been evidenced between metal contents and sample locations in relation the mining areas. The comparison between metals contents of the Amapari river and tributaries and those determinate by others authors in bottom sediments of a creek close to the Fe and Au mining plants of the Serra do Navio – Pedra Branca do Amapari confirms that hypothesis.