Search Results

You are looking at 1 - 10 of 85 items for :

  • "Marine sediments" x
  • Refine by Access: All Content x
Clear All
Journal of Radioanalytical and Nuclear Chemistry
Authors: G. García-Rosales, E. Ordoñez-Regil, J. Ramírez Torres, J. López Monroy, M. Machain-Castillo, and L. Longoria-Gándara

Abstract  

This study deals with the characterization of a marine sediments profile from the Gulf of Tehuantepec, Mexico. Ten sediment samples obtained from a core of 18.3 m of length were analysed. Although there have been numerous marine sediments studies carried out in Mexico, more are needed to better understand the sea floor formation. Crystallographic, morphologic, physical, chemical and gamma ray activity analysis were carried out on the samples. The analysis results showed a decrease in organic matter content as a function of sea depth; this value is related to the specific surface area. Some hazardous materials as Cr, Mn, Ni, Sr and Hg were also identified by PIXE in some samples, probably due to anthropogenic activity. The presence of uranium a naturally occurring element was found in all the samples, suggesting a migration through all materials of strata, radioactive elements such as 226Ra, 235U, 212Pb, 214Pb, 228Ac, 208Ti, 214Bi, 228Ac and 40K were detected.

Restricted access

Abstract  

In order to complete having data base of elemental assessment of the east coast of Peninsular Malaysia marine sediments along the South China Sea coasts, trace elements are analyzed and their distribution in marine sediments is undertaken. The present study is done parallel with pervious study on elemental assessment of heavy metals, rare earth elements and actinides in the marine sediments of the east coast of Peninsular Malaysia. Thirty surface sediment samples were collected in this area, including regions of Kelantan, Terengganu, Pahang, Rompin and Johor Baharu. Multielemental analysis was carried out by instrumental neutron activation analysis and inductively coupled plasma atomic emission spectroscopy. In both cases methodology validation was performed by certified reference material analyses. For the surface elemental distributions the enrichment factor values, average I geo and mC d values indicate that the trace elements of the surface sediments are uncontaminated in all sampling stations that are consistent with previous studies results of heavy metals, rare earth elements and actinides.

Restricted access

Abstract  

Results obtained from the analysis of sediments surface samples taken from rivers mouth and polluted marine environment were analyzed for REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy, Lu and Yb using instrumental neutron activation analysis. Thirty surface samples were collected from ten sites in the coastal marine sediments of the South China Sea along 957 km stretch of the east coast of Peninsular Malaysia. The samples prepared in the powdered form before irradiating them in a neutron flux of ~4 × 1012 n cm−2 s−1 at 750 kW power using the TRIGA Mark II research reactor at Malaysian Institute for Nuclear Technology (MINT). Results of the total concentration are used to establish baseline data in environmental pollution assessment and to develop the correlations between the Ce/Ce* anomalies and the distribution patterns of some the light rare earth elements (LREEs) and the heavy rare earth elements (HREEs). The Chondrite-normalized REE pattern from each site examined and used to explain the sedimentation patterns by anthropogenic activities and by natural processes such as shoreline erosion, weathering deposits. Shale-normalized (NASC) patterns suggest enrichment of LREEs relative to the HREEs with a positive Ce/Ce* anomaly. Validation of the used method was done using a Soil-7 SRM.

Restricted access

estimate the PCDD/Fs concentration levels in beach sand and marine sediment in different sites along the Jordanian Coast of Gulf of Aqaba to establish baselines for these compounds. 2. Materials and Methods 2

Open access

Abstract  

Forty elements in 21 coastal marine sediment samples collected duringthe second Antarctic scientific expedition from 18 different sites of Brekilenarea located at the coast of Antarctica were analysed by instrumental neutronactivation analysis (INAA) to detect eventual pollution. Radio-assay schemesfor three sets of elements after neutron irradiation and cooling were evolvedto avoid matrix effects. Data have been compared with those for sedimentsof various stations at Antarctica and two other regions in different continents.Lower concentration of certain elements in the Antarctic sediments reflectsless environmental exposition. Enrichment factors (EF) were calculated forall the elements using the earth crust as reference matrix, based on elementalvalues by MASON, TAYLOR and WEDEPOHL which show a normal pattern near to unityexcept for Ag and Br. The data obtained could also serve as a reference pointfrom which changes in the global environment can be studied. The quality assuranceof data was performed using standard reference materials (SRMs) of a similarmatrix (IAEA Marine Sediment SD-M/TM and Chinese Marine Sediment GBW 07313).

Restricted access

Abstract  

In this study, instrumental neutron activation analysis (INAA) and inductively coupled plasma-mass spectrometry (ICP-MS) were used to compare results obtained by both techniques for sediment samples collected from the Patras Harbour, Western Greece. The accuracy of the methods was tested using reference materials. In total seven elements were measured by both techniques (Zn, Ni, Cr, Ba, As, U, Co). Results obtained by ICP-MS were compared with those obtained by INAA by applying paired t-test. Insignificant differences in mean concentration values were found for Zn, Ni, Cr and Ba, whereas the differences for As, Co and U were significant. Correlations between element concentrations measured by both techniques are also discussed.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Gelen, N. López, O. D. Maslov, A. G. Belov, M. V. Gustova, O. Díaz, J. Beltrán, J. Soto, M. V. Manso Guevara, M. Pérez, and M. J. Simón

Summary  

Twenty six elements was studied preliminary in the superficial sediments of Havana Bay using gamma activation analysis by the electron accelerator microtron MT-25 at the Flerov Laboratory of Nuclear Reactions, JINR. Samples from five zones of Havana Bay including the three coves were analyzed. The obtained results show a close relation between the concentration levels of the studied elements and the pollution sources. Some elements (As, Ba, Ni, Pb, Cu, Zn, Fe, Cr, Mn) have high concentration levels compared to the values for other environmental marine sediments reported in the literature.

Restricted access

Abstract  

Procedures for determination of neptunium in marine sediment and seawatersamples are described. Iron hydroxide Fe(OH)2 –Fe(OH)3 is used for preliminary pre-concentration of neptunium. Secondly,neptunium Np4+ and Pu3+ are separated by tri-isooctylamine-(TIOA)extraction in 8–10M HCl by redox with SO3 2–-Fe3+ Neptunium Np4+ and uranium U6+ areseparated by back extraction the Np4+ with 2M HCl. Finally, theneptunium is purified from the uranium and thorium by anion exchange in 8MHNO3 and 12M HCl. The stripping of 6M HCl + NH2 OH HClfurther separates the neptunium Np3+ and uranium. Reduction bySO 32– –Fe3+ appeared to be an efficientway to obtain Np4+ The decontamination factors of the procedureare 4.0. 104 for 232 Th, 5.6 . 104 for uraniumand 1.6 . 104 for plutonium.

Restricted access

Abstract  

Two sediment cores were recovered in San Simón Bay (NW Spain) in order to establish sediment accumulation rates by 210Pb and 137Cs dating and to reconstruct metal pollution history. Sediment composition was determined by X-ray Fluorescence. A main lithogenic origin was shown up. Grain size conditions radionuclide activities and element concentrations. Fine grained sediments concentrate pollutants and showed higher activities. Radionuclide profiles are affected by diagenetic processes and sedimentary disturbances, but a temporal framework could be obtained for the intertidal area, where the anthropogenic inputs of Cu, Pb and Zn started several decades ago.

Restricted access

Abstract  

The homogeneity of IAEA RM SM-M-2/TM Marine Sediment was tested by INAA. The sampling constants a and b have been determined for 6 elements.

Restricted access