Estimation of annual effective dose due to natural and man-made radionuclides in the metropolitan area of the bay of Cadiz (SW of Spain)

In order to investigate the radiological hazard of naturally occurring radioactive material (NORM) and man-made Cs-137 radionuclide in the Bay of Cdiz, 149 samples of sediments have been analysed. Activity concentration in all the samples was determined using a HPGe detection system. Activity concentrations values of Ra-226, Th-232, K-40 and Cs-137 in the samples were 12.62.6 (2.540.6), 18.54.0 (2.873.4), 45145 (1051342) and 3.21.3 (0.216.0) Bq kg(1), respectively. Outdoor external dose rate due to natural and man-made radionuclides was calculated to be 35.791.69 (4.71119.16) nGy h(1) and annual effective dose was estimated to be 43.892.27 (5.78146.14) Sv y(1). Results showed low levels of radioactivity due to NORM and man-made Cs-137 radionuclide in marine sediments recovered from the Bay of Cdiz (Spain), discarding any significant radiological risks related to human activities of the area. Furthermore, the obtained data set could be used as background levels for future research.