Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Artigo | IMSEAR | ID: sea-219402

RESUMO

This article for the first time presents the results of the study of qualitative and quantitative elemental and amino acid composition of the aboveground part of the plant Nepeta olgae Regel (L.) taken in the territory of Chust and Kosonsai districts (from the slopes of Gova and Kosonsai mountains) of Namangan region during the period before and during flowering (May-June, 2021-2022). The use of instrumental analysis of high-throughput energy dispersive X-ray fluorescence spectrometry, allowed to establish 20 mineral elements in the plant Nepeta olgae Regel (L.), among which to vital 9 elements and 3 to conditionally necessary. The amino acid composition of the plant Nepeta olgae Regel (L.) was studied by high performance liquid chromatography (HPLC) and 17 compounds were identified. Of these, 8 were substitutable and 9 essential amino acids.

2.
Eng. sanit. ambient ; 26(5): 893-901, set.-out. 2021. tab, graf
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1346005

RESUMO

RESUMO A representatividade da amostragem é fundamental para embasar a tomada de decisão, uma vez que a heterogeneidade da matriz é o principal fator para incerteza dos dados nos estudos de gerenciamento de áreas contaminadas. Neste estudo, coletaram-se 112 amostras de solo superficial em malha quadrada de 1 x 1 m, em uma área 15 x 6 m, no campus regional de Resende da Universidade do Estado do Rio de Janeiro. Anteriormente, no terreno funcionaram empresas de produção de filmes radiográficos e purificação de prata metálica. As amostras de solo foram analisadas por pXRF, método de screening para metais. Com base nos dados levantados, calculou-se, por meio de métodos estatísticos, a quantidade de amostras que permitiriam uma caracterização representativa da área, considerando um erro relativo de 20% para dois intervalos de confiança: 95 e 80%. As análises indicaram concentrações superiores aos valores de referência para os parâmetros prata, mercúrio, chumbo, selênio e zinco. Os resultados de mercúrio possivelmente referem-se a ruído espectral, não estando relacionados ao histórico de uso e ocupação. Os coeficientes de variação das concentrações dos elementos analisados variaram de 132 a 225%. Considerando uma distribuição lognormal, calcularam-se 76 amostras para o maior intervalo de confiança e 53 para o menor. Isso seria o equivalente a transectos com espaçamentos de 1,47 e 2,11 m. Os resultados ratificam a necessidade de investigações de alta resolução nas áreas fonte, conforme recomendado pela Decisão de Diretoria da Companhia Ambiental do Estado de São Paulo nº 038/2017/C (DD-038).


ABSTRACT The representativeness of the sampling is fundamental to support decisions, since the heterogeneity of the matrix is the main factor for data uncertainty in contaminated areas management studies. In this study, 112 surface soil samples were collected in a square mesh of 1 x 1 m, in an area of 15 x 6 m, at the Campus Regional de Resende (CRR) of Universidade do Estado do Rio de Janeiro (UERJ). Previously, companies of radiographic films production and metallic silver purification operated in this area. The soil samples were analyzed by pXRF, a screening method for metals detection. Based on the data collected, the number of samples that would allow a representative characterization of the area was calculated, using statistical methods, considering a relative error of 20% for 80 and 95% confidence intervals. The analyses indicated concentrations higher than the reference values for the parameters silver, mercury, lead, selenium, and zinc. The results of mercury possibly refer to spectral noise, not being related to the history of use and occupancy. The coefficient of variation of the soil obtained ranged from 132 to 225%. Considering a lognormal distribution, 76 samples were calculated for the highest confidence interval and 53 for the lowest. This would be the equivalent of transects with spacings of approximately 1.47 and 2.11 m. The results confirm the need for high resolution investigations in the source areas, as recommended by the Executive Board Decision of CETESB No. 038/2017/C (DD-038).

3.
Eng. sanit. ambient ; 26(2): 211-219, Mar.-Apr. 2021. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1249750

RESUMO

ABSTRACT Wood is a renewable material considered eco-friendly and used for various purposes. While wood treated with chromated copper arsenate (CCA) does not deteriorate, its final disposal may entail risks due to the concentration and toxicity of the components. The removal of CCA from wood can be achieved in different ways. This study focuses on the reduction of the concentrations of Cu, Cr, and As chemical species by the electro-removal technique, aiming to obtain biomass with low deleterious potential that would allow multiple uses or safe disposal in landfills. The analytical results showed reductions of 79.5, 87.4, and 81.3% in the mean concentrations of Cu, Cr, and As, respectively. It is worth mentioning the occurrence of the fungus Xylaria sp. after treatment 6 (60 min, 5 g, and 25 V), further suggesting that the method was effective. Samples of these fungi were identified from isolates by culture in medium, DNA extraction, and sequencing of the Internal Transcribed Spacer (ITS) region.


RESUMO A madeira é um material renovável, considerado ecologicamente correto e utilizado para diversos fins. Embora a madeira tratada com arseniato de cobre cromado (CCA) não se deteriore facilmente, seu descarte final pode acarretar riscos devido à concentração e toxicidade dos componentes. A remoção do CCA da madeira pode ser realizada de diferentes maneiras. Este estudo teve como foco a redução das concentrações de espécies químicas Cu, Cr e As pela técnica de eletro-remoção, visando obter uma biomassa com baixo potencial deletério que permitiria múltiplos usos ou disposição final segura em aterros sanitários. Os resultados analíticos mostraram reduções de 79,5; 87,4 e 81,3% nas concentrações médias de Cu, Cr e As, respectivamente. Vale ressaltar a ocorrência do fungo Xylaria sp. após o tratamento 6 (60 min, 5 g e 25 V), sugerindo ainda que o método foi eficaz. Amostras desses fungos foram identificadas dos isolados por meio de cultura em meio, extração de DNA e sequenciamento da região do espaçador transcrito interno (ITS).

4.
Nucleus (La Habana) ; (67): 28-32, ene.-jun. 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1143356

RESUMO

Abstract Concentrations of nickel, copper, zinc and lead in surface sediments from 16 stations located in Mampostón sub-watershed (Mayabeque, Cuba) were estimated by X-ray fluorescence analysis. The Cu, Zn and Pb contents in sediments shows a different level of contamination across the studied stations. The application of modified degree of contamination (mCd) allowed to classify the metal pollution in Ganuza and Mampostón rivers and in Pedroso reservoir. The comparison with Sediment Quality Guidelines and toxicity mean quotients shows that 100% of the sediments are associated with the occasional presence of possible adverse effects to human health.


Resumen Se determinan, por Fluorescencia de Rayos X, las concentraciones de Níquel, Cobre, Zinc y Plomo en los sedimentos superficiales de 16 estaciones en la subcuenca Mampostón (Mayabeque, Cuba).Los contenidos de Cu, Zn y Pb en los sedimentos muestran diferentes niveles de contaminación en las estaciones estudiadas. La aplicación del grado de contaminación modificado (mCd) permitió clasificar como alta o baja la contaminación de los ríos Ganuza y Mampostón, así como del embalse Pedroso. La comparación con las Guías de Calidad de Sedimentos y del cociente promedio de toxicidad, mostró que el 100% de los sedimentos estudiados están asociados a la presencia ocasional de posibles efectos adversos a la salud humana.

5.
Nucleus (La Habana) ; (66): 18-21, jul.-dic. 2019. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1091395

RESUMO

RESUMEN Una de las direcciones de aplicación de la Ciencia de Materiales que realiza el Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear CEADEN es el apoyo mediante un grupo de técnicas físicas a la restauración y el mantenimiento de estructuras y objetos de la ciudad de La Habana, entre otras localidades de Cuba, que poseen interés artístico y social . En el presente trabajo se abordan varias aplicaciones en la caracterización de materiales para contribuir a las actividades de conservación del patrimonio cultural e histórico cubano que se encuentra en La Habana. Se presentan dos ejemplos de análisis por las técnicas de Fluorescencia de Rayos X y Difracción de rayos X de los pigmentos de obras en lienzos y de la paleta de una reconocida artista de la plástica cubana; así como el de tejas cerámicas que fueron utilizadas en la restauración de los techos de la residencia conocida como Casa Verde de 5ta Avenida en el Municipio Playa.


ABSTRACT One of the applications in Materials Science carried out at the Center for Technological Applications and Nuclear Development (CEADEN) is the technical support through several methods used, based on applied Physics for the restoration and maintenance of structures and objects holding artistic and social relevance in Havana city. The aim of this paper is to present two examples of X -ray Fluorescence and Diffraction materials characterization, intended to support conservation and restoration activities of the Cuban cultural and historic heritage: analyzed objects were pottery roof tiles for the restoration of the mansion known as The Green House at 5th Avenue, Miramar, as well as pigments from a Cuban fine artist's canvas and palette.

6.
Nucleus (La Habana) ; (66): 58-65, jul.-dic. 2019. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1091402

RESUMO

RESUMEN Se resumen las diferentes experiencias en la aplicación de las técnicas nucleares y conexas en el estudio de diversos problemas ambientales de la Ciudad de La Habana. El análisis medioambiental mediante las técnicas de Análisis por Activación Neutrónica (AAN) y Gamma (AAG), Fluorescencia de Rayos X (FRX), Espectrometría por Absorción Atómica (EAA) y por Inducción de plasma acoplado (ICP), así como la Espectrometría Gamma de Bajo Fondo (EGBF), han permitido obtener información muy relevante sobre el comportamiento de los metales pesados, antibióticos y radionúclidos en los sedimentos marinos y fluviales, suelos urbanos y agrícolas, aguas, arenas de balnearios, polvos urbanos y productos de la agricultura urbana de la ciudad de La Habana.


ABSTRACT Various nuclear and related analytical techniques applied to study different environmental problems in Havana city are presented. The environmental analysis by means of Neutron and Gamma Activation analyses, X-ray Fluorescence Atomic Abortion and Induced Coupled Plasma spectroscopies and Low Background , Gamma Spectrometry, have allowed to obtain important information about the behavior of heavy metals, antibiotics and radionuclides in sediments, urban and agricultural soils, waters, beach sands, urban dusts and agricultural products farmed in the Havana city.

7.
Chinese Medical Journal ; (24): 1959-1964, 2019.
Artigo em Inglês | WPRIM | ID: wpr-802777

RESUMO

Background@#Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy.@*Methods@#Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10% (sensitization-challenge; late phase group); 10% NiSO4-group, 10% to 10% (sensitization-challenge; early-phase group); and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES).@*Results@#In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (<200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni2+ aqueous ionic state but in the nickel-binding protein.@*Conclusions@#This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni2+ aqueous ionic state but bound with certain proteins to form a complex in the stratum corneum in ACD model tissue.

8.
Rev. bras. ciênc. saúde ; 23(2): 173-178, 2019. ilus.
Artigo em Português | LILACS | ID: biblio-1010305

RESUMO

Introdução: A Barba de timão é uma planta de origem do cerrado brasileiro, que vem sendo estudada por suas propriedades medicinais, tais como: antibacteriana, cicatrizante, coagulante sanguíneo, dentre outras. A cicatrização é um processo pelo qual o organismo tende a reparar uma lesão ou perda de tecido. Objetivo: Este trabalho compara a composição química da barba de timão com algumas pomadas cicatrizantes de origem farmacêuticas já presentes e disponíveis no mercado. Assim, pode-se relacionar a propriedade cicatrizante desta planta por meio de seus componentes químicos. Materiais e Métodos: Para realizar tal comparação, foi utilizada com amostra a planta barba de timão comercializada em mercados especializados e as pomadas, sulfato de neomicina e a sulfadiazina de prata. Para a análise multielementar, foi utilizada a espectroscopia por fluorescência de raios X (XRF). Com o espectro fornecido pela XRF foi possível comparar os elementos químicos das amostras. Conclusão: O espectro mostrou que a barba de timão tem propriedades químicas semelhantes, assemelhando-se com os componentes químicos encontrados na amostra de sulfato de neomicina, adicionada de três compostos químicos, K, Ca e Br, que também são importantes no processo de cicatrização. Ao comparar com a sulfadiazina de prata, o único elemento que se difere do fitoterápico, além do três já citados, é a Ag. (AU)


Introduction: Barba de timão is a plant of the Brazilian Cerrado origin, which is already studied for its medicinal properties, such as: antibacterial, healing, blood coagulant, etc. Healing is a process by which the body tends to repair an injury or loss of tissue. Objective: This work compares the chemical composition of barba timão with some pharmaceutical healing scouring ointments already present and used in the market. Thus, we can relate the healing properties of this plant. Material and Methods: In order to make such a comparison, it was used the barba timão plant marketed in specialized markets, and the ointments neomycin sulfate and silver sulfadiazine. For multielement analysis, X-ray fluorescence spectroscopy (XRF) was used. With the spectrum provided by the XRF it was possible to compare the chemical elements of the samples. Conclusion: The spectrum shows that the barba timão has similar chemical properties, it resembles the chemical components found in the sample of neomycin sulfate, but with three more chemical compounds that is K, Ca and Br, that are also important in the healing process. When comparing with silver sulfadiazine, the only element that differs beyond the K and Ca of the phytotherapic, is the Ag of the ointment sample. (AU)


Assuntos
Anti-Infecciosos Locais , Bases para Pomadas/farmacologia
9.
Chinese Journal of Analytical Chemistry ; (12): 570-577, 2018.
Artigo em Chinês | WPRIM | ID: wpr-692285

RESUMO

Epsilon 3xenergy dispersive X-ray fluorescence spectrometer (EDXRF) was used to analyze the major and minor elements in marine sediments collected from the Indian Ocean on-site. Results obtained by EDXRF were compared with those by inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) in the laboratory A total of 24 elements in marine sediment samples,namely Al2O3,MgO,Fe2O3,Na2O,K2O,CaO,Mn,P,Ti,Ba,Sr,V,Zn, Zr, Co,Ni,Cu,Ga,Rb,Y,Nb,Mo,Nd,Pb and Th were measured,and a good agreement was found for these elements(R2>0.9),except for Al2O3,and Ga,Nb and Th with content lower than 30 μg/g. The mean relative deviations of EDXRF method were less than 10% for all of the above mentioned major elements, except for MgO in low concentration and P in high concentration. The mean relative deviations were less than 25% for all of the above mentioned trace elements,except for Sr(>700 μg/g),Mo(<20 μg/g) and Nb. In general, precision and accuracy of EDXRF method were good enough for detection of marine sediments. Taking into account all these facts, the EDXRF method proposed here was proved to be an effective tool for element determination in marine sediment on-site,and it would provide a new technical support to investigate the spatial distribution of mineral resources in marine geological survey.

10.
Chinese Journal of Analytical Chemistry ; (12): 517-523, 2018.
Artigo em Chinês | WPRIM | ID: wpr-692278

RESUMO

A method for the determination of trace elements such as lead, arsenic and mercury in cream cosmetics by total reflection X-ray fluorescence spectrometry (TXRF) with suspension sampling was developed. The mixed solvents of water,tetrahydrofuran,methanol and were used to disperse paste, cream, and additives of triton X-100 to promote the test liquid uniform. The test suspension fluid were taken into the sample carrier,drying and then introduced into TXRF. Poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) was added to curing sediments,inhibiting proliferation. Triton X-100 and P(VP-co-VAc) were found to have the function of reducing mercury loss in the drying process. The loss of elements in the drying process and the effect of triton X-100 and P(VP-co-VAc) were investigated. The effect of cream matrix, element interference, spectral line and the inner standard were discussed. The calibration curves for quantitative analysis were established using matrix standards, so the error of software decomposition peak and the error caused by thick sample were avoided within a certain range. In this work,the linear correlation coefficients of Pb,As and Hg calibration curve were greater than 0.998 The detection limit of Pb,As and Hg in the solution were 0.005,0.004 and 0.006 μg/mL,respectively. Relative standard diviations(RSDs, n=11) of Pb, As and Hg were 7.8%-14.9%,6.6%-13.3% and 7.6%-14.6% respectively. The results of Pb, As, and Hg in cream cosmetics determinated by this method agreed with those obtained from inductively coupled plasma atomic emission spectrometry and the value of standard reference material. The TXRF method was proved to be accurate,simple and valuable in determination of trace heavy metal ions in cosmetic samples.

11.
Nucleus (La Habana) ; (61): 1-5, Jan.-June 2017.
Artigo em Inglês | LILACS | ID: biblio-841901

RESUMO

Heavy metal (Co, Ni, Cu, Zn and Pb) content in muds from some Cuban spas (San Diego, Elguea, Santa Lucía and Cajío) have been studied using X-ray fluorescence. The measured metal contents are in the same order of magnitude as those reported for average Earth’s upper crust average shales and muds as well as with worldwide reported peloids. The comparison with sediment quality guidelines (SQGs) shows a different degree of pollution for peloids from each studied spa. Nevertheless, the estimated sum of metal/probable effect level value ratios (0.9 - 2.4) correspond to a low potential acute toxicity of contaminants. Therefore, the heavy metal content present in peloids from the studied Cuban spas is not an obstacle for its use with therapeutic purposes


Se estudia mediante la técnica de Fluorescencia de rayos X, el contenido de metales pesados (Co, Ni, Cu, Zn y Pb) en lodos terapéuticos provenientes de varios balnearios cubanos (San Diego, Elguea, Santa Lucía y Cajío). Los contenidos de metales pesados determinados en los lodos terapéuticos se encuentran en el mismo orden que los reportados para lodos y esquistos representativos de la corteza terrestre, así como para lodos utilizados en balnearios internacionalmente. La comparación con las Guías de Calidad de sedimentos muestran diferentes grados de polución para los lodos de cada balneario. Independientemente de ello, los valores de las razones suma de metales/nivel de efecto probable (0,9-2,4) corresponden a un bajo potencial agudo de toxicidad por contaminantes. De esta manera, el contenido de metales pesados presentes en los lodos de los balnearios estudiados no representa impedimento alguno para su uso con fines terapéuticos.

12.
Chinese Medical Equipment Journal ; (6): 118-120, 2017.
Artigo em Chinês | WPRIM | ID: wpr-617171

RESUMO

Objective To determinate the heavy metal cadmium content in rice to ensure food safety.Methods Several brands and batch numbers of rice were collected and divided into groups A and B.Group A contained 24 pieces of rice from the canteens,and group B involved in 22 pieces from the farm product markets.Cadmium content in rice was detected quantitatively with X-ray fluorescence spectrometer,and then evaluated according to GB 2762-2012 which determined rice was not qualified in case cadmium content was more than 0.2 mg/kg.Results Group A had cadmium content between 0.00 and 0.477 mg/kg,the times of ultra standard being 2.385 and the disqualification rate being 29.2% (7/24),and group B had cadmium content between 0.065 and 0.619 mg/kg,the times of ultra standard being 3.095 and the disqualification rate being 68.2% (15/22).Excessive cadmium content in rice occurred in both canteens and markets,while the canteens was better than the markets.Conclusion X-ray fluorescence spectrometer detects cadmium content in rice rapidly and simply,and is worthy promoting in elementary facilities.

13.
Chinese Journal of Analytical Chemistry ; (12): 1129-1136, 2017.
Artigo em Chinês | WPRIM | ID: wpr-611745

RESUMO

To reveal the mechanism of Cu enrichment of alfalfa, in-situ micro-X-ray fluorescence spectrometry (μ-XRF) and fractional extraction were used to explore in-situ Cu distribution information in alfalfa seedlings and different combination forms of Cu in organs.The results showed that alfalfa roots were enriched with Cu up to 12.06 mg/g, which was 8 times of stem and 4.9 times of leaves.The in-situ μ-XRF result showed that the root of alfalfa was the main site of enrichment of Cu, and there was a barrier of Cu at the rhizome junction to alleviate the toxic effect of excess Cu on the shoots.Excess Cu (more than 50 μmol/L) also inhibited the uptake of Zn and Ca in alfalfa, enhanced the uptake of Fe in alfalfa, but had no obvious effect on the uptake of K and Mn.Plant fractional extraction showed that the Cu in root cells was mainly fixed in the form of insoluble residues (41%) and cell wall chelate (20%), while in the stem, Cu existed as four forms including hydrophobic protein binding, cell wall binding state, residual state and water-soluble state, which further reduce the excess transport of Cu to the leaves.In the leaves, excess Cu in the leaf cells was mainly in the vacuole and insoluble residue to achieve tolerance and detoxification to Cu.

14.
Chinese Journal of Analytical Chemistry ; (12): 1309-1315, 2017.
Artigo em Chinês | WPRIM | ID: wpr-609373

RESUMO

Moss has high tolerance and accumulating capacity to heavy metal.In this study, the distribution of heavy metal elements in moss sampled from lead-zinc mine was analyzed by X-ray fluorescence spectrometry.The speciation of lead was analyzed by X-ray absorption near-edge spectroscopy.Research showed that the contents of Pb, Zn, Cd and As in the moss of the mining area were extremely high, and their maximum concentration were 1.06 mg/g , 1.23 mg/g, 30.5 μg/g, 13.2 μg/g, respectively.Besides, the shoots especially the new tissue of the moss were the major sites for accumulation and storage of heavy metals.The micro-distribution characteristics varied among Hypnum plumaeforme and Brachytheciumprocumbens, indicating the difference of different species of moss in absorption pathway, accumulation and tolerance mechanisms for heavy metal.Linear combination fitting results indicated that the main lead speciation in moss was lead phosphate (78%) and lead oxide (22%), which suggested that the precipitation of lead phosphate might be the main mechanism of tolerance for moss.

15.
Chinese Journal of Analytical Chemistry ; (12): 1372-1377, 2016.
Artigo em Chinês | WPRIM | ID: wpr-503546

RESUMO

To investigate the mechanism of lead biosorption and biotransformation in lead-resistant bacteria in microcosmic scale, synchrotron radiation micro X-ray fluorescence (μ-SRXRF ) and X-ray absorption near edge structure ( XANES) was used to determine the element distribution characteristics and speciation of lead ( Pb) in lead-resistant bacteria strain isolated from farmland soil samples taken from a lead-zinc mine in Lanping county, Yunnan province in China. The isolated species was identified to be Arthrobacter sp. The concentration of Pb biosorpted in lead-resistant bacteria was directly determined byμ-SRXRF, and the results showed that the highest concentration was 5925μg/g and the bioaccumulate factor was 14 . 8 . Speciation of Pb in lead-resistant bacteria B2, LB ( Lysogeny Broth) medium and soil were also presented after using Pb LⅢXANES. Compared with Pb LⅢ XANES peak shape and peak position between standard samples, it was demonstrated that the Pb in lead-resistant bacteria was mainly formed by amorphous forms like PbS (58. 0%), (C17H35COO)2Pb (22. 2%), Pb5(PO4)3Cl (19. 8%) rather than organic Pb speciation which was exist in LB medium. Therefore, the isolated lead-resistant bacteria could biotransform Pb to sulfuric compounds. The biotransformation regular could be of great interest for other investigators as reference in study of bioavailability impact factor of heavy metals.

16.
Nucleus (La Habana) ; (58): 34-38, jul.-dic. 2015.
Artigo em Espanhol | LILACS | ID: lil-775531

RESUMO

Concentrations of Cr, Co, Ni, Cu, Zn, Pb and Fe in the street dust from Camagüey city were studied by X-ray .uorescence analysis. The mean Cr, Co, Ni, Cu, Zn and Pb contents in the urban dust samples (97 ± 30, 14 ± 2, 35 ± 36, 94 ± 26, 199 ± 87 and 42 ± 29 mg.kg-1 dry weight, respectively) were compared with mean concentrations in other cities around the world. Spatial distribution maps indicated the same behaviour for Cr-Ni and Pb-Zn-Cu, respectively, whereas the spatial distribution of Co differs from other heavy metals. The metal-to-iron normalization, using Cuban average metal soil contents as background, showed that street dusts from Camagüey city are moderately or significantly Zn-Pb enriched in those areas associated with heavy traffic density and metallurgic plant location. However, the calculation of the potential ecological risk index shows that metal content in Camagüey street dust does not represent any risk for the city population.


Se determinan por fluorescencia de rayos X las concentraciones de Cr, Co, Ni, Cu, Zn y Pb en los polvos urbanos de la ciudad de Camagüey. Los contenidos medios de metales pesados en las muestras de polvos urbanos (97 ± 30, 14 ± 2, 35 ± 36, 94 ± 26, 199 ± 87 y 42 ± 29 mg.kg-1 en peso seco respectivamente) son comparados con las concentraciones medias determinadas en otras ciudades del mundo. Los mapas de distribución espacial indican comportamientos similares para Cr-Ni y Pb-Zn-Cu respectivamente, en tanto la distribución espacial de Co difiere del resto de los metales. La normalización a un metal de referencia, empleando como fondo los valores medios de concentraciones de metales pesados cubanos, mostró que los polvos urbanos de la ciudad de Camagüey tienen un enriquecimiento moderado o significativo de Zn y Pb en aquellas áreas que están asociadas a una elevada densidad del tráfico automotor y a la ubicación de plantas metalúrgicas. El cálculo del índice de riesgo ecológico potencial mostró que el contenido de metales pesados en los polvos urbanos de Camagüey no representa riesgo alguno para su población.

17.
Nucleus (La Habana) ; (57): 38-43, Jan.-June 2015.
Artigo em Inglês | LILACS | ID: lil-754877

RESUMO

Concentrations of Cr, Co, Ni, Cu, Zn and Pb in the topsoils (0-10 cm) from ten farms located in the vicinity of a steel-smelter plant at Cotorro (Havana, Cuba) were measured by X-ray fluorescence analysis. The concentration ranges of Cr, Co, Ni, Cu, Zn and Pb were 54-186, 15-39, 19-137, 50-945, 91-7739 and 21-731 dry weight respectively. The metal mean contents in the farm topsoil samples were compared with metal contents reported for soils from the vicinity of other smelters worldwide. The Metal-to-Iron normalisation and estimation of the integral pollution indexes allowed observing that most metal polluted soils are from those farms, and that their location coincide with the prevalent wind direction in the studied area. The enrichment index values show that metal concentrations in soils from these farms are above the permissible levels for urban agriculture.


Se determinan por fluorescencia de rayos X las concentraciones de Cr, Co, Ni, Cu, Zn y Pb en los suelos superficiales (0-10 cm) de 10 granjas agrícolas, localizadas en la vecindad de la planta de acero del Cotorro (La Habana, Cuba). Los rangos de concentraciones de Cr, Co, Ni, Cu, Zn y Pb fueron de 54-186, 15-39, 19-137, 50-945, 91-7739 y 21-731 de peso seco respectivamente. Los contenidos medios de metales pesados en los suelos superficiales de las granjas se comparan con los niveles de metales pesados reportados en la literatura para suelos adyacentes a plantas de acero. La normalización de los metales al hierro y la estimación del los índices de polución integral, permitió determinar que los suelos contaminados por metales pesados fueron aquellos, cuya ubicación coincide con la dirección predominante de los vientos en la zona estudiada. Los valores delíndice de enriquecimiento mostraron que las concentraciones de metales pesados en los suelos de esas granjas, superan los niveles permisibles para la agricultura urbana.

18.
Nucleus (La Habana) ; (55): 11-14, ene.-jun. 2014.
Artigo em Inglês | LILACS | ID: lil-738988

RESUMO

Concentrations of chromium, nickel, copper, zinc and lead in surface sediments from six stations located in Nuevitas Bay (Cuba) were estimated by X-ray fluorescence analysis. The Cr content in sediments shows a strong variation across the studied stations (89-513 ), in contrast with the other elements studied. The application of modified degree of contamination () classifies as moderate the contamination of Nuevitas Bay. The comparison with Sediment Quality Guidelines (SQGs) and toxicity mean quotients shows that 100 % of the sediments are associated with the occasional presence of possible adverse effects to human health.


Se determinan, mediante el análisis por fluorescencia de rayos X, las concentraciones de cromo, níquel, cobre, zinc y plomo en sedimentos superficiales de seis estaciones de la Bahía de Nuevitas en Cuba. El contenido de cromo se determinó con un intervalo de gran variación (89-513 ) en las estaciones estudiadas. La aplicación del grado de contaminación modificado () clasificó la contaminación de los sedimentos de la Bahía de Nuevitas como de “grado moderado”. La comparación con las Guías de Calidad de Sedimentos y del cociente promedio de toxicidad, mostró que el 100 % de los sedimentos estudiados están asociados a la presencia ocasional de posibles efectos adversos a la salud humana.

19.
Nucleus (La Habana) ; (54): 8-11, jul.-dic. 2013.
Artigo em Inglês | LILACS | ID: lil-738982

RESUMO

Zinc content and Zn bioaccumulation in crops (rice and some vegetables and condiments) cultivated in 18 Cuban urban and suburban areas are reported. Zinc content in food and the corresponding farming soil samples was determined by X-Ray Fluorescence analysis and by Atomic Absorption spectrometry. The quality of the analysis was verified using the Certified Reference Materials IAEA 393 «Algae¼, MA-B-3/TM «Fish Tissue Lyophilised¼, IAEA V-10 «Hay¼ and IAEA Soil-7. The obtained results show rice, of the studied crops, as the major Zn bioaccumulator and important Zn source in Cuban human diet.


Se reportan los contenidos de zinc y su bioacumulación en cultivos (arroz, vegetales y condimentos) procedentes de 18 áreas de agricultura urbana y suburbana. El contenido de zinc en los alimentos, así como en sus correspondientes suelos de cultivo, fue determinado por Fluorescencia de Rayos X y por Espectrometría de Absorción Atómica. La calidad del estudio se verificó mediante el análisis de los Materiales de Referencia Certificados IAEA 393 «Algae¼, MA-B-3/TM «Fish Tissue Lyophilised¼, IAEA V-10 «Hay¼ e IAEA Soil-7. Los resultados mostraron al arroz, de los cultivos estudiados, como el cultivo de mayor bioacumulación de zinc y como fuente importante de Zn en la dieta de nuestra población.

20.
Nucleus (La Habana) ; (53): 19-23, ene.-jun. 2013.
Artigo em Inglês | LILACS | ID: lil-738978

RESUMO

Behavior of heavy metals (Fe, Co, Ni, Cu, Zn and Pb) content in -dated healing mud profiles from San Diego river outlet (western Cuba) has been studied using X-ray fluorescence analysis. Iron-normalized enrichment factors indicate the Co, Ni, Cu and Zn natural origin (Enrichment Factor ¼ 1), reflecting a low anthropogenic impact to the area in the last 100 years. A minor lead enrichment (EF = 2) in the last few decades was determined. The heavy metal levels in most recent mud (0-5 cm, on mg.kg-1 dry weight) were: Co = 18 ± 2, Ni = 62 ± 8, Cu = 52 ± 2, Zn = 72 ± 4 and Pb = 28 ± 2. The comparison with reported Earth’s upper crust average shales and muds, and with data reported for different muds used for medical purposes shows that heavy metal content in San Diego River mud is suitable for its use with therapeutic purposes.


Se determinan los niveles de metales pesados (Fe, Co, Ni, Cu, Zn y Pb) en perfiles de sedimentos del río San Diego, fechados con la técnica de y mediante la técnica de Fluorescencia de Rayos X. La normalización al hierro de los contenidos de metales pesados indicó el origen natural de los elementos Co, Ni, Cu y Zn, así como un muy moderado enriquecimiento en Pb, reflejando el bajo impacto antropogénico que ha tenido esta área en los últimos 100 años. Los niveles de metales pesados en los lodos más recientes (0-5 cm, en peso seco) fueron: Co = 18 ± 2, Ni = 62 ± 8, Cu = 52± 2, Zn = 72 ± 4 y Pb = 28 ± 2. La comparación con los contenidos de metales pesados, reportados en la literatura en lodos de uso medicinal, mostró que el contenido de metales pesados en los lodos del río San Diego es aceptable para su empleo con fines terapéuticos.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA