Uranium and thorium isotopes in some Red Sea sediments

Alpha-emitting isotopes of uranium and thorium in surface marine sediments collected from the harbours at Port Sudan and Sawakin on the Sudanese coast of the Red Sea have been studied using radiochemical separation procedures and alpha-particle spectrometry. Activity concentrations of U-238, U-235, U-234, Th-232, Th-230 and Th-228 were measured. The ranges of activities ob served for U-238 and Th-232 were 2.71-13.42 Bq/kg and 3.62-18.73 Bq/kg from Port Sudan and 3.87-24.79 Bq/kg and 1.13-10.03 Bq/kg dry weight from Sawak in, respectively. The behaviour of these decay-series nuclides was examined using daughter/parent and non-isotopic specific activity ratios in sedimen ts. Simple regression analysis showed insignificant correlation between ura nium and thorium activities and the organic matter content in sediments. Th e results are compared with those from coastal waters of other oceans.