Anthropogenic radionuclides in the water column and a sediment core from the Alboran Sea: application to radiometric dating and reconstruction of historical water column radionuclide concentrations

Global fallout is the main source of anthropogenic radionuclides in the Mediterranean Sea. This work presents 137Cs, 239+240Pu and 241Am concentrations in the water column in the southwest Alboran Sea, which was sampled in December 1999. A sediment core was taken at 800 m depth in the area (35°47′ N, 04°48′ W). 210Pb, 226Ra, 137Cs and 239+240Pu specific activities were measured at multiple depths in the core for dating purposes. 137Cs and 239+240Pu profiles did not show defined peaks that could be used as time markers, and they extended up to depths for which the 210Pb-based constant rate of supply (CRS) dating model provided inconsistent dates. These profiles can be useful to test dating models, understood as particular solutions of a general advection–diffusion problem, if the time series of radionuclide inputs into the sediment is provided. Thus, historical records of depth-averaged 137Cs and 239+240Pu concentrations in water, and their corresponding fluxes into the sediment, were reconstructed. A simple water-column model was used for this purpose, involving atmospheric fallout, measured distribution coefficient (k d) values, and a first-estimate of sedimentation rates. A dating model of constant mixing with constant sedimentation rate was applied successfully to three independent records (unsupported 210Pb, 137Cs and 239+240Pu), and provided the objective determination of mixing parameters and mass sedimentation rate. These results provide some insight into the fate of atmospheric inputs to this marine environment and, particularly, into the contribution from the Chernobyl accident.International Atomic Energy Agency Research Project RAF/7/00

Reference material for radionuclides in sediment IAEA-384 (Fangataufa Lagoon sediment)

Author Posting. © Springer, 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Radioanalytical and Nuclear Chemistry 273 (2007): 383-393, doi:10.1007/s10967-007-6898-4.A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides in the environment, as well as for the development and validation of analytical methods and for training purposes. The material is available from IAEA in 100 g units

Reference Material for Radionuclides in Sediment, IAEA-384 (Fangataufa Lagoon Sediment)

The IAEA Marine Environment Laboratory (IAEA-MEL) in Monaco has conducted intercomparison exercises on radionuclides in marine samples for many years as part of its contribution to the IAEA's program of Analytical Quality Control Services (AQCS). An important part of the AQCS program has been a production of Reference Materials (RMs) and their provision to radioanalytical laboratories. The RMs have been developed for different marine matrices (sediment, water, biota), with accuracy and precision required for the present state of the art of radiometrics and mass spectrometry methods. The RMs have been produced as the final products of world-wide intercomparison exercises organized during last 30 years. A total of 44 intercomparison exercises were undertaken and 39 RMs were produced for radionuclides in the marine environment. All required matrices (seawater, biota, sediment) have been covered with radionuclide concentrations ranging from typical environmental levels to elevated levels affected by discharges from nuclear reprocessing plants. The long-term availability of RMs (over 10 years) requires the use of very specific techniques to collect and pretreat large quantities of material (e.g., in excess of 100 kg) in order to ensure sample stability and homogenization of any analytes of interest. The production of a RM is therefore a long process, covering the identification of needs, sample collection, pre-treatment, homogenization, bottling, distribution to laboratories, evaluation of data, preliminary reporting, additional analyses in expert laboratories, certification of the material, and finally issuing the RM. In this paper we describe a reference material IAEA-384, Fangataufa lagoon sediment, designed for determination of anthropogenic and natural radionuclides in the marine environment. This RM has been prepared with the aim of testing the performance of analytical laboratories to measure the activity of these radionuclides in a sediment sample contaminated by elevated levels of fallout from nuclear weapons tests. Participating laboratories were requested to determine as many radionuclides as possible by radiometric (alpha, beta and gamma-spectrometry) as well as by mass spectrometry methods (e.g., ICPMS - Inductively Coupled Plasma Mass Spectrometry, TIMS - Thermal Ionization Mass Spectrometry, AMS - Accelerator Mass Spectrometry)

Intérêt de la FRX-RT (Fluorescence des Rayons X à Réflexion Totale) pour le suivi de la pollution des eaux des rivières par les métaux : Cas de oued Bouregreg (Maroc)

Les analyses des métaux dans les eaux de l'estuaire de Bouregreg, ont été effectuées par fluorescence des rayons X à réflexion totale (FRX-RT). L'objectif étant d'une part d'évaluer le taux en éléments majeurs et traces dans l'estuaire de Bouregreg, d'autre part de promouvoir cette technique d'analyse d'échantillons liquides. La FRX-RT, est une technique multiélémentaire qui permet d'analyser des échantillons liquides ou des suspensions. On peut ainsi déterminer les métaux dans la phase liquide et la phase particulaire (matières en suspension : MES) avec une précision de 5 à 15 %, en réalisant préalablement des préparations adéquates très simples des échantillons. La validation des résultats est assurée par l'analyse d'une solution standard de référence (ICP multielement standards). Les limites de détection observées dans nos conditions sont de l'ordre de 50 à 5 ppb selon l'élément considéré. Par ailleurs, les teneurs en différents éléments ont été contrôlés par spectrométrie d'absorption atomique

Analyse multi-élémentaire par fluorescence X à dispersion d'énergie des apports fluviatiles et des sédiments superficiels de la plate-forme atlantique du Maroc

L'analyse multi-élémentaire d'une trentaine de sédiments d'oueds et de l'océan atlantique du Maroc a été réalisée en utilisant des spectromètres X à dispersion d'énergie et des sources radioactives d'excitation en Fer-55, Cd-109 et Am-241. Les échantillons ont été collectés de la plate-forme continentale atlantique, de Tanger à Agadir et des oueds situés entre ces deux villes. Les objectifs de cette analyse sont : * la caractérisation géochimique des sédiments en vue de l'approche du transfert de matière du continent vers l'océan en tenant compte des données morphologiques, climatiques et géologiques de l'environnement sédimentaire. Les échantillons ont été prélevés par benne de la plate-forme continentale atlantique et des lits des oueds suivants, du Nord vers le Sud : Tahaddart, Loukkos, Sebou, Bou Regreg, Oum er Rbia, Tensift et Souss. Les régions du Nord dont la plupart sont irriguées présentent un climat humide alors que celles du Sud ont un climat semi-aride à aride avec des oueds intermittents. * la détermination de pollutions possibles de la zone littorale en relation avec l'activité anthropique, principalement au large des zones urbanisées. la précision des résultats a été évaluée par l'analyse de deux matériaux standards de référence de 1'AIEA (Agence International de 1'Energie Atomique), le sédiment «SL-1» et le sol «soil-7». Cette précision est de 5% pour la plupart des éléments majeurs alors qu'elle n'est que de 10 à 20% pour les éléments traces.The XRF analysis of about 30 sediments from Moroccan oueds (rivers) and atlantic continental shelf for the content of major and trace elements has been performed, utilizing the energy dispersive X-ray spectrometer and radio-isotope excitation with Fe-55, Cd-109 and Am-241 annular sources. Samples have been collected from Moroccan atlantic continental shelf from Tanger to Agadir and oueds between these cities. The objectives of this analysis were : * to determine the geochemical areas on Moroccan atlantic continent, * to explain the mechanisms of sediment transport from the continent to the sea throw the oueds using morphological, climate and hiterland impacts. Thus, sample have been collected from atlantic continental shelf and the following oueds, from the north with a humid climate and irrigated areas to the south with a semi-arid to arid climate : Tahaddart, Loukkos, Sebou, Bou Regreg, Oum er Rbia, Tensift and Souss, * to assess the eventual pollution of the coast by human activities, mainly at regions which are very urbanized. Results were assessed for the accuracy by the analysis of standard reference materials from IAEA (International Atomic Energy Agency), soil-7 and SL-1 sediment. The results obtained for most of the major elements were accurate to about 5% while the accuracy of trace element determination was much worse, 10 to 20%

Air pollution assessment of Salé's city (Morocco)

Four sites were selected in Sale's city in Morocco in order to contribute in air pollution level assessment and determination of its effects on public health. The sites were selected so that they are close to the most important industrialized areas, they have a very high demographic density and they cover a heavy traffic. Two approaches of air sampling and subsequent analysis methods of elements in atmospheric aerosols have been performed. The first is a classical approach, which consists in sampling total airborne materials with a High Volume Sampler and analysing the samples using Atomic Absorption Spectroscopy (AAS). The second is having its interest for studies relating effects of particles on human health. It consists in employing a Dichotomous Sampler to collect inhalable particles and the X-ray Fluorescence (XRF) for elemental analysis. With such system, it was possible to collect separately respirable and inhalable aerosols. The ED-XRF analysis method used is appropriate for monitoring airborne polluants in living and working areas with advantage of simple preparation, nondestructive nature, rapidity and suitable limits of detection. Using this method, it was possible to identify and quantify S, Ca, CI, Fe, Cu, and Pb. With Atomic Absorption Spectroscopy Analysis Method, we quantified Cd. This study have been completed by measuring NO$_x$ SO$_2$ and solid suspended particles or airborne particulate matter (APM)

A context-specific perspective of equal employment opportunity in Islamic societies

The purpose of the paper is to offer a context-specific perspective of gender equality and its implications for equal employment opportunity in Islamic societies. The paper discusses various discourses on the Islamic perspective of gender and how they might impact female employment in the formal employment sector. The study highlights some major differences among Muslim countries with respect to gender ideology and the corresponding prospects for equal employment opportunity. Furthermore, the paper argues that any attempts to reform the socio-political institutions and labor policies in Islamic societies must be informed by their particular formal and informal institutional features