Distribution and environmental impact of radionuclides in marine sediments along the Venezuelan coast

The activity concentrations of Cs-137, K-40, Ra-226 and Th-232 in Bq/kg from 42 marine sediment samples collected at nine sampling sites were determined in order to establish a radiological baseline along the Venezuelan coast. The radioactivity levels were determined by means of a gamma-ray spectroscopy system using a hyper-pure germanium detector in a low-background configuration. Particle size distribution and total organic matter content were also determined. Activity concentrations of Cs-137 were lower than the detection limit of the analytical technique (0.9 Bq/kg) in all studied sites. The results suggest that the variation of grain-size distribution is one of the most important factors influencing the spatial variations of K-40, Ra-226 and Th-232 in sediments along the Venezuelan coasts. In all sampling sites, average concentrations of K-40, Ra-226 and Th-232 were lower than the world average values. Activity concentrations of Ra-226, Th-232 and K-40 in coastal marine sediments along the Venezuelan coast could be considered to be low when compared with global average values, indicating that they are not apparently above of the range that might be considered normal or background. These results suggest that the studied sites do not pose any significant radiological threat to the population. The results attained in this study should be of considerable value as baseline data and background reference levels for Venezuelan coastlines.