Heavy metal concentrations in some organs of African catfish (Clarias gariepinus) from Eko-Ende Dam, Ikirun, Nigeria

The contents of the heavy metals Fe, Zn, Cu, Mn, Pb, Cd and As were examined in the liver, heart, gills, kidney and muscles of the fish Clarias gariepinus from Eko-Ende dam in Ikirun, the capital of Ifelodun Local Government of Osun State, Nigeria. C. gariepinus is the fish of choice and the most demanded in the southwest of Nigeria. The highest metal concentrations were in the liver and the gills while the lowest was in the muscles. The general deceasing order of metal accumulation in the organs was Fe > Zn > Cu > Mn > Cd. Lead and arsenic were not detected in any organ. The values were of lower concentrations than found in many other dams and rivers in Nigeria and some other countries. The values were also lower than the FAO/WHO recommended maximum limits in fish samples, making the fish to be safe and not of any hazards for the consumers.

Effects of dietary manganese on growth and tissue manganese concentrations of juvenile gibel carp, Carassius auratus gibelio

A 68-day growth trial was conducted in a flow-through system to determine the effect of dietary manganese levels on growth and tissue manganese concentration of juvenile gibel carp (Carassius auratus gibelio). Seven purified diets containing 7.21, 8.46, 9.50, 10.50, 13.03, 19.72 and 22.17 mg manganese (as manganic sulfate) per kilogram diet were fed to triplicate groups of fish (initial weight 3.21 +/- 0.01 g). The results showed that dietary manganese levels did not significantly affect feed intake of the fish. Specific growth rate, feed efficiency, total hepatic superoxide dismutase activity, carcass and skeletal manganese concentration increased significantly with increased dietary manganese(P < 0.05) while condition factor decreased significantly(P < 0.05). It was concluded that dietary requirement of manganese was 13.77 mg Mn per kilogram diet. Carcass and skeletal manganese concentration could also be used to evaluate the manganese requirement. Total hepatic superoxide dismulase activity was not a sensitive indicator for dietary requirement.

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coatings sampled and surficial sediments collected in the Songhua River, China

Natural surface coatings sampled (NSCSs) from the surface of shingles and surficial sediments (SSs) in the Songhua River, China were employed to investigate the similarities and difference in fractions of heavy metals (Fe, Mn, Zn, Cu, Pb, and Cd) between NSCSs and SSs using the modified sequential extraction procedure (MSEP). The results show that the differences between NSCSs and SSs in Fe fractions were insignificant and Fe was dominantly present as residual phase (76.22% for NSCSs and 80.88% for SSs) and Fe-oxides phase (20.33% for NSCSs and 16.15% for SSs). Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase (48.27%) and that in SSs present as residual phase (45.44%). Zn, Cu, Pb and Cd were found dominantly in residual fractions (>48%), and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution pattern implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter (OM), and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.

Concentrations of Cadmium and Zinc in Seawater of Bohai Bay and Their Effects on Biomarker Responses in the Bivalve Chlamys farreri

Both in-field chemical investigation and in the laboratory toxic tests were carried out to systematically understand the pollution status of cadmium (Cd) and zinc (Zn) in Bohai Bay. Samples collected from surface seawater were determined to describe the distributions of Cd and Zn in Bohai Bay. The average values in our study of Cd and Zn were 0.15 mu g/L and 19.68 mu g/L, respectively. Both of them were lower than the first class limit of seawater quality standard in China. In the laboratory, antioxidant enzymes [SOD (Cu/Zn-SOD, Mn-SOD), CAT], lipid peroxidation (MDA), phase I and phase II enzymes (CYP4501A and GST) were investigated in the bivalves Chlamys farreri exposed to Cd and Zn at the concentration levels of Bohai Bay seawater, which were obtained from our in-field investigation. The reduced SOD, CAT, and EROD (7-ethoxyresorufin-O-deethylase) activities (with the inhibitory rate of 16.8%, 31.5%, and 51.6%, respectively) in Cd treatment were observed and resulted in obvious lipid peroxidation damage. However, treatment of Zn showed elevations in SOD and GST by 13.3% and 29.9%, respectively, and with no influence on lipid peroxidation. In summary, seawater quality in Bohai Bay seawater was ranked as good in general, but it seemed that Cd might possess a potential environmental risk by effecting pro-oxidant/antioxidant balance and phase I detoxification in C. farreri.

Trace metal concentrations in suspended particles, sediments and clams (Ruditapes philippinarum) from Jiaozhou Bay of China

Suspended particulate matter (SPM), sediments and clams were collected at three sites in Jiaozhou Bay to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 40.11-203; Zn: 118-447; Pb: 50.1-132; Cd: 0.55-4.39; Cr: 147.6-288; Mn: 762-1670 mu g/g), sediments (Cu: 17.64-34.26; Zn: 80.79-110; Pb: 24.57-49.59; Cd: 0.099-0.324; Cr: 41.6-88.1; Mn: 343-520 mu g/g) and bivalves (Cu: 6.41-19.76; Zn: 35.5-85.5; Pb: 0.31-1.01; Cd: 0.51-0.67; Mn: 27.45-67.6 mu g/g) are comparable to those reported for other moderately polluted world environments. SPM showed a less clear pattern. Metal concentrations in sediments displayed a clear geographical trend with values increasing with proximity to major urban centers. The clams (on dry weight) showed a complex pattern due to the variability introduced by age-related factors. Cd showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations. Zn, Pb and Mn showed no clear geographical pattern, whereas Cu increased in the clams collected in the most industrialized area. In addition, the bioaccumulation factors (BAF) were calculated. The result indicated that the studied Ruditapes philippinarum in Jiaozhou Bay possessed different bioaccumulation capacities for Cd, Zn, Cu, Pb and Mn, and Cd, Zn had a relatively high assimilation of those metals from sediment particles. A significant relationship with clam age was observed for Zn (positive) and Cu (negative) suggesting different physiological requirements for both metals with age. Trace metal concentrations measured in the tissue of the investigated clam were in the range considered safe by the WHO for human use.

Reactivity of Inorganic Mn and Mn Desferrioxamine B with O2, O2–, and H2O2 in Seawater

Manganese (Mn) is a required element for oceanic phytoplankton as it plays a critical role in photosynthesis, through its unique redox chemistry, as the active site in photosystem II, and in enzymes that act as defenses against reactive oxygen species (ROS), most notably for protection against superoxide (O2?), through the action of superoxide dismutase (SOD), and against hydrogen peroxide (H2O2) via peroxidases and catalases. The distribution and redox speciation of Mn in the ocean is also apparently controlled by reactions with ROS. Here we examine the connections between ROS and dissolved Mn species in the upper ocean using field and laboratory experimental data. Our results suggest it is unlikely that significant concentrations of Mn(III) are produced in the euphotic zone, as in the absence of evidence for the existence of strong Mn(III) ligands, Mn(II) reacts with O2? to form the short-lived transient manganous superoxide, MnO2+, which may react rapidly with other redox species in a manner similar to O2?. Experiments with the strong Mn(III) chelator, desferrioxamine B (DFB), in seawater indicated that the Mn(III) species are unlikely to form, as formation of the precursor Mn(II) complex is hindered due to the stability of the Ca complex with DFB.

Excitation and Emission Characteristics of Pretreated SrS:Mn:Ce Phosphors

Excitation and emission spectra of SrS : Mn : Ce phosphors have been studied in detail at various Mn and Ce concentrations. In order to study the effect of external pressure on phosphors, the samples were pretreated under various pressures. Four bands around 470 nm, 530 nm, 310 nm and 620 nm were observed, when the samples were excited with 265 nm radiation. The effect of pressure is to reduce the fluorescence ability of the phosphors, and the luminescence vanishes above O· 1 ton m-2 pressure. The fluorescence ability, however, can be regained on retiring the sample. The emission mechanism has been attributed to two luminescentcenters in the forbidden gap. An appreciable amount of photocurrent has also been observed for the sample.

Adsorção de Mn (II) e Zn (II) em soluções aquosas usando perlita expandida revestida com quitosana

In this work, chitosan was used as a coating of pure perlite in order to increase the accessibility of the groups OH- e NH2+the adsorptionof ions Mn2+ e Zn2+.The characterization results of the expanded perlite classified as microporous and whose surface area 3,176 m2 g-1after the change resulted in 4,664 m2g-1.From the thermogravimetry(TG) it was found that the percentage of coating was34,3%.The infrared analysis can prove the presence of groups Si-OH, Si-O e Al-O-Siresulting from the perlite and C=O, NH2and OH characterization of chitosan. The experiments on experiments on the adsorption of Mn and Zn were performed in the concentration range of10 a 50 mgL-1and the adsorption capacity inpH 5,8 e 5,2 was 19,49 and 23,09 mgg-1to 25 oC,respectively.The adsorption data were best fitted to Langmuir adsorption model to Langmuir adsorption model for both metalionsisindicative of monolayer adsorption. The kinetics of adsorption were calculated from the equation of Lagergren fitting the model pseudo-second-order for all initial concentrations, suggesting that adsorption of ions Mn2+ and Zn2+ follows the kinetics of pseudo-second-order and whose constant Speedk2(g/mg.min) are 0,105 e 3,98 and capacity and maximum removal qe 4,326 e 3,348,respectively.In this study we used a square wave voltammetry cathodic stripping voltammetry to quantify the adsorbed ions, and the working electrode glassy carbon, reference electrode silver / silver chloride and a platinum auxiliary electrode. The attainment of the peaks corresponding to ions Mn2+ and Zn2+ was evaluated in and electrochemical cell with a capacity of 30 mL using a buffer system (Na2HPO4/NaH2PO4)at pH 4 and was adjusted with solutionsH3PO4 0,1molL-1and NaOH 0,1 molL-1and addition of the analyte has been a cathodic peak in- 0,873 Vand detection limit of2,55x10-6molL-1para Zn.The dough used for obtaining the adsorption isotherm was 150 mg and reached in 120 min time of equilibrium for both metal ions.The maximum adsorption for 120 min with Mn concentration 20 mgL-1 and Zn 10 mgL-1,was91, 09 e 94, 34%, respectively

Simultaneous and Direct Determination of As, Bi, Pb, Sb, and Se and Co, Cr, Cu, Fe, and Mn in Milk by Electrothermal Atomic Absorption Spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Equilibrium, Thermoanalytical and Spectroscopic Studies to Characterize Phytic Acid Complexes with Mn(II) and Co(II)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ethanolic extract of Casearia sylvestris and its clerodane diterpen (caseargrewiin F) protect against DNA damage at low concentrations and cause DNA damage at high concentrations in mice's blood cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Simultaneous determination of Al, As, Cu, Fe, Mn, and Ni in fuel ethanol by GFAAS

A method has been developed for the simultaneous determination of Al, As, Cu, Fe, Mn, and Ni in fuel ethanol by graphite furnace atomic absorption spectrometry (GFAAS) using a transversely heated graphite atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of analytes during the pyrolysis and atomization stages using the mixture Pd(NO3)(2) + Mg(NO3)(2) as the chemical modifier was investigated in 0.028 mol L-1 HNO3, 0.14 mol L-1 HNO3, and diluted ethanol (1 + 1, v/v) containing different nitric acid concentrations. With 5 rhog Pd + 3 mug Mg as the modifiers, pyrolysis and atomization temperatures of the heating program of the atomizer were fixed at 1200 C and 2200degreesC respectively. For 20 muL of diluted sample (10 muL ethanol + 10 muL of 0.28 mol L-1 HNO3) dispensed into the graphite tube, analytical curves in the 2.0 - 50 mug L-1 Al, As, Cu, Fe, Mn, Ni ranges were established. The calculated characteristic masses were - 37 pg Al, 73 pg As, 31 pg Cu, 16 pg Fe, 9 pg Mn, and 44 pg Ni, and the lifetime of the tube was around 2 50 firings. The limits of detection (LOD) based on integrated absorbance were 1.2 mug L-1 Al, 2.5 mug L-1 As. 0.22 mug L-1 Cu, 1.6 L-1 Fe 0.20 mug L-1 Mn 1.1 mug L-1 Ni. The relatively standard deviations (n = 12) were less than or equal to 3%, less than or equal to 6%, less than or equal to 2%, less than or equal to 3.4%, less than or equal to 1.3%, and less than or equal to 2% for Al, As, Cu, Fe, Mn, and Ni, respectively, the recoveries of Al, As, Cu, Fe, Mn and Ni added to fuel ethanol samples varied from 77% to 112%, 92% to 114%, 104% to 113%, 73% to 116%, 91% to 122% and 93% to 116%, respectively. Accuracy was checked for Al, As, Cu, Fe, Mn, and Ni determination in 20 samples purchased at local gas stations in Araraquara city, Brazil. A paired t-test showed that the results were in agreement at the 95% confidence level with those obtained by single-element GFAAS.

A influência dos elementos traços , (B, Cu, Mn, Mo e Zn) na produção de ramnolipídios por pseudomonas aeruginosa LBI

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propriedades varistoras de sistemas a base de 'SN''OIND.2' dopados con 'ZN''O', 'W''OIND.3', 'NBIND.2''OIND.5', 'ALIND.2''OIND.3', 'CRIND.2''OIND.3', 'MN''OIND.2', 'CO''O', 'CU''O', 'V''CLIND.3'

Pós-graduação em Química - IQ

Evaluation of diffusive gradients in thin films technique (DGT) for measuring Al, Cd, Co, Cu, Mn, Ni, and Zn in Amazonian rivers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)