Radioactivity distribution in surface and core sediment of the central part of the algerian coast: An estimation of the recent sedimentation rate

Abstract

Sediment core samples and marine surface sediments of identical composition, mostly muddy, were collected using a Van Veen type grab and a box corer on board the M.S. Benyahia research vessel (ISMAL), along the Algerian littoral, between Algiers (36°49.9 N/ 03° 02.3 E) and Cherchell (36° 39.4 N/ 02° 12.4 E), during a sampling cruise in September 1997. The samples were analysed to determine the activity concentration of natural radionuclides (uranium and thorium series and 40K as well) and artificial radionuclides (137Cs and Pu isotopes), using a direct gamma spectrometry for gamma emitters and radiochemical separations and alpha spectrometry for alpha emitters. The horizontal and vertical distribution of the examined radionuclides were studied in the surface and core samples and an effort to estimate the sedimentation rate was attempted.The measured values range was: 17 - 26 Bq/Kg dry for uranium series radioisotopes, 18 - 32 Bq/Kg dry for thorium series radioisotopes, 311 - 690 Bq/Kg dry for 40K, 0.4 - 11 Bq/Kg dry, for 137Cs and 0.4 - 1.0 Bq/Kg dry for 239 + 240Pu.