Determination of gamma-emitting radionuclides in the inter-tidal sediments off Balochistan (Pakistan) Coast, Arabian Sea

Natural radionuclide contents of 226Ra, 228Ra and 40K were studied for inter-tidal sediments collected from selected locations off the 745 km long Balochistan Coast using HPGe detector based gamma-spectrometry system. The sampling zone extends from the beaches of Sonmiani (near Karachi metropolis) through Jiwani (close to the border of Iran). The natural radioactivity levels detected in various sediment samples range from 14.4±2.5 to 36.6±3.8 Bq kg-1 for 226Ra, 9.8±1.2 to 35.2±2.0 Bq kg-1 for 228Ra and 144.6±9.4 to 610.5±23.9 Bq kg-1 for 40K. No artificial radionuclide was detected in any of the marine coastal sediment samples. 137Cs, 60Co, 106Ru and 144Ce contents in sediment samples were below the limit of detection. The measured radioactivity levels are compared with those reported in the literature for coastal sediments in other parts of the world. The information presented in this paper will serve as the first ever local radioactivity database for the Balochistan/Makran Coastal belt of Pakistan. The presented data will also contribute to the IAEA's, Asia-Pacific Marine Radioactivity Database (ASPAMARD) and the Global Marine Radioactivity Database (GLOMARD). (authors)