Distribution of Natural Radioactivity,137Cs,90Sr, and Plutonium Isotopes in a Water Column and Sediment Core along the Algerian Coast

Abstract

Concentrations of natural (40K,210Pb, uranium, and thorium series) and artificial radioelements (137Cs,90Sr,239+240Pu) were determined in seawater and sediment samples collected from stations along the Algerian coast. Seawater was collected from the surface to a maximum depth of 2000 m; the sediment cores were sampled from a depth of around 1500 m. This work was carried out in August 2001, in the framework of the Regional African project /7/004 (RAF), by the accomplishment of an oceanographic campaign organized by the International Atomic Energy Agency (IAEA) in collaboration with Commissariat à l'Energie Atomique (COMENA) and L'Institut des Sciences de la Mer et de L'Amenagement du Littoral (ISMAL), on board of the research vessel of M.S. Benyahia of ISMAL. In addition to the record of the conductivity (mS) and temperature (°C) data at each station, seawater samples were treated and preconcentrated on board, those of sediment cores were divided into different layers in order to undergo analyses in the laboratory of radiological impact studies of Algiers. Concentration results were obtained for137Cs and90Sr in mBq/L and239+240Pu inμBq/L in seawater, and also for natural and artificial radionuclides in Bq/kg dry weight in the layers of the sediment cores. The different profiles of137Cs,239+240Pu,90Sr, and210Pb concentrations against depth were presented to show artificial radioactivity distribution in the water column and sediment core. Concentrations of137Cs in the sediment core were also used to identify the137Cs peak in the area of interest.