Emiss��es naturais e antr��picas de nitrog��nio, f��sforo e metais para a bacia do Rio Maca�� (Maca��, RJ, Brasil) sob influ��ncia das atividades de explora����o de petroleo e g��s na Bacia de Campos

Emission factors of natural processes and anthropogenic activities were used to estimate nutrients and metal loads for the lower Maca�� river basin, which hosts the operational base for the offshore oil and gas exploration in the Campos Basin. The estimates indicated that emissions from anthropogenic activities are higher than natural emissions. Major contributing drivers include husbandry and urbanization, whose effluents receive no treatment. The increasing offshore oil exploration along the Brazilian littoral has resulted in rapid urbanization and, therefore might increase the inshore emission of anthropogenic chemicals in cases where effective residue control measures are not implemented in fluvial basins of the region.

S��ntese, caracteriza����o e atividade fotocatal��tica de catalisadores nanoestruturados de TiO2 dopados com metais

Titanium dioxide nanostructured catalysts (nanotubes) doped with different metals (silver, gold, copper, palladium and zinc) were synthesized by the hydrothermal method in order to promote an increase in their photocatalytic activity under visible light. The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy and specific area and pore volume determination. The materials' photocatalytic activity was evaluated by rhodamine B decomposition in a glass batch reactor. Under UV radiation, only nanotubes doped with palladium were more active than the TiO2 P25, but the samples doped with silver, palladium and gold exhibited better results than the undoped samples under visible light.

A etimologia de biomol��culas com metais de transi����o como auxiliar na aprendizagem de Qu��mica Biol��gica

Numerous functional biomolecules are associated with metals, i.e. the metallobiomolecules; more specifically, some are dependent on transition metals required for several crucial biological roles. Nevertheless, their names can lead to ambiguous interpretations concerning the properties and performances of this group of biological molecules. Their etymology may be useful by providing a more perceptive insight into their features. However, etymology can lead to incongruous conclusions, requiring an especially careful approach to prevent errors. Examples illustrating these subjects shall be examined.

M��todo hidrometal��rgico para reciclagem de metais terras raras, cobalto, n��quel, ferro e mangan��s de eletrodos negativos de baterias exauridas de Ni-MH de telefone celular

A hydrometallurgical method for the recovery of rare earth metals, cobalt, nickel, iron, and manganese from the negative electrodes of spent Ni - MH mobile phone batteries was developed. The rare earth compounds were obtained by chemical precipitation at pH 1.5, with sodium cerium sulfate (NaCe(SO4)2.H2O) and lanthanum sulfate (La2(SO4)3.H2O) as the major recovered components. Iron was recovered as Fe(OH)3 and FeO. Manganese was obtained as Mn3O4.The recovered Ni(OH)2 and Co(OH)2 were subsequently used to synthesize LiCoO2, LiNiO2 and CoO, for use as cathodes in ion-Li batteries. The anodes and recycled materials were characterized by analytical techniques.

Influ��ncia das subst��ncias h��micas de sedimentos na biodisponibilidade de metais para o sistema aqu��tico

In rivers, sediments act as sinks for retaining contaminants. This study evaluated the influence of sediment humic substances (HS) on the bioavailability of metals. The levels of metals in sediments and HS indicated that most are complexed with HS. Characterization of HS showed a high degree of humification. The complexation capacity of HS for metals established the affinity order:Pb2+<Cd2+<Co2+<Ni2+<Cu2+<Zn2+<Mn2+<Fe2+. Chemometric analysis demonstrated a correlation between the structural characteristics of HS and complexation capacity of metals.

Desenvolvimento de reator tipo "dip catalyst" para filmes polim��ricos contendo nanopart��culas de metais de transi����o

This article describes the development of a new catalytic reactor designed to operate with nanoparticle-embedded polymer thin films. Stabilization of metal nanoparticles in films that serve as catalysts in organic reactions is relatively new; therefore, the development of reactors to facilitate their use is necessary. We describe in detail the preparation of the GDCR reactor-type "dip catalyst" and its evaluation in the Suzuki - Miyaura cross-coupling reaction of phenylboronic acid and 4-bromoanisole catalyzed by palladium nanoparticle-embedded cellulose acetate thin film (CA/PD(0)). Compared with earlier prototypes, GDCR reactor showed excellent results when operating with CA/PD(0) thin films.

AVALIA����O DE M��TODOS DE SOLUBILIZA����O PARA DETERMINA����O DE METAIS EM GLICERINA PROVENIENTE DA PRODU����O DE BIODIESEL POR T��CNICAS DE ESPECTROMETRIA AT��MICA

This paper describes the evaluation of simple and fast solubilization methods for the determination of Ca, Mg, and K in glycerin samples from biodiesel production by atomic spectrometry. The solubilization in water was compared with two other methods: solubilization in formic acid and solubilization in ethanol. Using solubilization in water, determination of the three analytes was possible; the values of limits of detection for Ca, K, Mg were 0.31, 0.06, and 0.16 mg kg&#8722;1, respectively. Because no adequate reference material was available, the accuracy was evaluated by assessing the recoveries tests with both solubilization methods; the evaluation ranged from 90% to 115%, with values of relative standard deviation >8%, indicating good accuracy of the measure. Four crude glycerin samples obtained from biodiesel plants of Rio Grande do Sul were analyzed after treatment with the different methods of solubilization, and the obtained results of Ca, Mg, and K concentration were in agreement with the values obtained from both solubilization methods. Therefore, solubilization in water is concluded to be a simpler, faster, and viable method for sample preparation of glycerin.

AN��LISE EXPLORAT��RIA DAS CONCENTRA����ES DOS METAIS NA, CA, MG, SR E FE EM EXTRATO AQUOSO DE PETR��LEO, DETERMINADOS POR ICP OES, AP��S OTIMIZA����O EMPREGANDO PLANEJAMENTO DE EXPERIMENTOS

AbstractThe purpose of this study was to evaluate the best operating conditions of ICP OES for the determination of Na, Ca, Mg, Sr and Fe in aqueous extract of crude oil obtained after hot extraction with organic solvents (ASTM D 6470-99 modified). Thus, the full factorial design and central composite design were used to optimize the best conditions for the flow of nebulization gas, the flow of auxiliary gas, and radio frequency power. After optimization of variables, a study to obtain correct classification of the 18 samples of aqueous extract of crude oils (E1 to E18) from three production and refining fields was carried out. Exploratory analysis of these extracts was performed by principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA), using the original variables as the concentration of the metals Na, Ca, Mg, Sr and Fe determined by ICP OES.

AVALIA����O DA BIOACUMULA����O DE METAIS EM Cyprinus carpio PELA INTERA����O COM SEDIMENTO E ��GUA DE RESERVAT��RIO

Bioaccumulation of Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined in the gills and liver of Cyprinus carpio and related to concentrations in the sediment and water of the Alagados Reservoir, Ponta Grossa/Paran��. Cd and Fe exceeded the legal limit for water. Fe was the most abundant metal in the reservoir's water and sediment. The metals in the sediment were below the level of probable adverse effects on biota. There were no significant differences between sampling sites for water and sediment. Liver and gills had higher concentrations of Al, Fe and Zn, with a significant increase in Al (P > 0.05) compared to the increase in weight and size of the specimens. Statistically, gills showed higher concentrations of Al, Cd, Co, Cr, Mn and Zn and liver higher concentrations of Cu and Fe. Co, Cu, Fe, Mn and Zn showed significant differences (P < 0.01) between the organs. The bioaccumulation factors (BAF) showed that the interaction of water with gills promotes greater accumulation of metals in this organ. Despite the low concentrations in the reservoir, bioaccumulation of metals in gills and liver of C. carpio occurs by its interaction with contaminated water and sediment, respectively.

USO DO PLANEJAMENTO EXPERIMENTAL PARA OTIMIZA����O DE UM PROCEDIMENTO VOLTAM��TRICO PARA DETERMINA����O SIMULT��NEA DAS CONCENTRA����ES DOS METAIS Zn, Cd, Pb E Cu LIVRES EM ��GUA DE COCO

Optimization of the main parameters of SWASV using boron-doped diamond electrode was described for the simultaneous determination of Zn, Cd, Pb and Cu free in coconut water. The values of electroanalytical parameters studied were optimized with the factorial design and center composite design. The optimized parameters for the preconcentration of metals were -1.50 V for potential, and 240 s for deposition time. For SWV, the optimized value was 11.56 mV for step potential. In addition, frequency and pulse height were defined at 100 Hz and 55 mV, respectively. Furthermore, the concentration of the supporting electrolyte (acetate buffer, pH 4.7) was optimized in 0.206 mol L-1. The optimized procedure was applied in two samples of coconut water: natural and processed. The limits of detection (LOD) obtained for Zn, Cd, Pb and Cu were 7.2; 4.4; 3.3 and 1.5 ��g L-1, respectively. The concentrations of Cd and Pb were not detected. On the other hand, the values found for the concentrations of Zn and Cu were: < LOD (29 ��g L-1) and (6.8 �� 0.9) ��g L-1 for the natural sample; and (85.8 �� 4.2) ��g L-1 and (7.7 �� 0.6) ��g L-1 for the processed sample, respectively.

Uso da an��lise explorat��ria de dados na avalia����o de modificadores qu��micos para determina����o direta e simult��nea de metais em ��lcool combust��vel por GFAAS

O objetivo deste trabalho foi empregar a an��lise explorat��ria de dados, no caso, a t��cnica de an��lise de componentes principais (PCA) como ferramenta na avalia����o de modificadores qu��micos na determina����o direta e simult��nea de Al, As, Cu, Fe, Mn e Ni em ��lcool et��lico combust��vel por espectrometria de absor����o at��mica em forno de grafite (GFAAS). Os modificadores qu��micos avaliados foram: Pd(NO3)2 + Mg(NO3)2; W/Rh; W+ co-inje����o de Pd(NO3)2 + Mg(NO3)2 e para cada modificador foram utilizadas trintas amostras de ��lcool et��lico combust��vel. Como dados experimentais foram utilizados os resultados dos testes de adi����o e recupera����o dos analitos frente aos diferentes modificadores qu��micos estudados. O emprego da t��cnica de PCA possibilitou a separa����o dos tipos de modificadores em fun����o do intervalo de recupera����o do analito. Dentre os modificadores avaliados, W+ co-inje����o de Pd(NO3)2 + Mg(NO3)2 apresentou-se como a esp��cie de maior correla����o positiva, pois apresenta os maiores teores de recupera����o, e sendo assim, foi o escolhido para o desenvolvimento de metodologia para determina����o direta e simult��nea de Al, As, Cu, Fe, Mn e Ni em ��lcool et��lico combust��vel por GFAAS.

Efeito da complexa����o de metais aos antiinflamat��rios na a����o contra agentes oxidativos e radicais livres: a����o do cetoprofeno

Os radicais livres s��o esp��cies altamente reativas geradas nos organismos vivos com a finalidade de prote����o. Por��m, em algumas circunst��ncias, estes s��o respons��veis pela ocorr��ncia ou o agravo de danos teciduais. Muitos antiinflamat��rios apresentam a����o direta sobre radicais livres e esp��cies reativas n��o radicalares, o que contribui para suas a����es contra a inflama����o. O cetoprofeno �� um antiinflamat��rio n��o esteroidal que gera radicais livres ao sofrer fotoirradia����o e tem com isso um efeito hemol��tico importante. A complexa����o de metais a diferentes f��rmacos tem sido utilizada como estrat��gia para melhorar a a����o farmacol��gica de diferentes mol��culas e reduzir seus efeitos colaterais. Neste trabalho s��o apresentados resultados do estudo de a����o do cetoprofeno e seus complexos de c��rio e cobre sobre radicais livres e sobre eritr��citos. Observou-se que o c��rio intensifica as propriedades scavenger do cetoprofeno sobre radicais livres enquanto o cobre intensifica as a����es sobre oxidantes n��o radicalares. O cobre ainda reduziu o efeito hemol��tico apresentado pelo cetoprofeno e mantido pelo seu derivado de c��rio.

Toler��ncia de fungos ectomicorr��zicos e plantas associadas a n��veis t��xicos de metais

As ectomicorrizas s��o associa����es entre ra��zes de plantas e fungos, de grande import��ncia para a sobreviv��ncia e crescimento vegetal, por aumentar o aporte nutricional e a prote����o contra fatores adversos. Os fungos ectomicorr��zicos podem quelar ��ons de metais t��xicos, retirando-os do solo e diminuindo os danos ao hospedeiro. Quatro isolados de fungos ectomicorr��zicos foram utilizados neste estudo: UFSC-Sc68 (Scleroderma sp.); UFSC-Ch163 (Chondrogaster angustisporus); UFSC-Pt116 e UFSC-Pt188 (Pisolithus microcarpus). Mudas de Eucalyptus dunnii foram testadas quanto �� sua toler��ncia aos metais alum��nio (Al), c��dmio (Cd), cromo (Cr) e mangan��s (Mn) misturados ao substrato de plantio, em dois experimentos em casa de vegeta����o. No primeiro, em aus��ncia dos fungos e, no segundo, ap��s inocula����o com esses organismos. No experimento sem inocula����o, o metal mais t��xico foi o Cr. Nenhuma planta sobreviveu nas doses 1000 e 10000 mg.kg-1 desse metal. Para os outros metais, a mat��ria seca diminuiu com o aumento da dose. J�� no estudo com plantas inoculadas, o Cd foi o metal mais t��xico, que reduziu significativamente a sobreviv��ncia e o crescimento das plantas. Os isolados f��ngicos UFSC-Pt188 e UFSC-Ch163 foram os mais eficientes na prote����o contra os metais, melhorando a sobreviv��ncia e a produ����o de mat��ria seca das plantas. O isolado UFSC-Ch163, em particular, foi o mais eficiente na toler��ncia das plantas, o que indica seu potencial de utiliza����o em solos contaminados para favorecer o estabelecimento e o crescimento das plantas.

Teores de metais na biomassa de Egeria densa, Egeria najas e Ceratophyllum demersum

Este estudo foi realizado com o objetivo de se estimar o conte��do de elementos met��licos presentes em tr��s macr��fitas aqu��ticas submersas, procurando avaliar a participa����o destas plantas na remo����o destes elementos na ��gua e criar base de dados que permita prever o impacto ambiental do descarte delas em solo ou na pr��pria ��gua. As amostras foram desidratadas, mo��das e encaminhadas aos laborat��rios para an��lise e quantifica����o dos elementos. Para as tr��s esp��cies, a maior concentra����o de elementos foi observada durante o ver��o, ocorrendo decl��nio nas concentra����es durante o inverno, principalmente para os elementos van��dio e chumbo. N��o foi detectada presen��a do elemento merc��rio em nenhuma das amostras.