137Cs in seawater and sediment along the Algerian coast

Abstract

Abstract In order to define a baseline of natural and anthropogenic radionuclides, a sampling campaign along the Algerian coast was organised during the last quarter of 1999 to collect seawater and sediment samples. A total of 25 surface and water column samples were collected along the coast. In addition to a sediment core at Annaba station at the eastern coast, 41 surface sediment samples were collected each 25 km along the coast. 137 Cs activity concentrations in surface seawater ranged from 1.69 ± 0.11 to 3.3 ± 0.2 Bq / m 3 with a mean value of 2.03 ± 0.13 Bq / m 3 . A slight increase of 137 Cs activity (within a factor of two) from the western to the eastern coast of Algeria was observed. The 137 Cs water profiles had peaks at 80–100 m water depths. Massic activities of 137 Cs in surface sediment samples varied between 8.15 and 35.4 Bq/kg dry weight. The observed differences could be due to several reasons, namely the nature and composition of the sediment, and the water depth at the sampling location. Corresponding inventories of 137 Cs in the water column and sediment core were calculated, and a sedimentation rate using unsupported 210 Pb was estimated to be 0.2 cm/year.