Abstract
Twenty marine sediment samples were collected ( from the ground surface down to depth of 0.50 m) from the south beach located on the western part of Jeddah. The samples were analyzed by XRD spectroscopy for the chemical and mineral compositions, results show that the major concentrations for the samples are ALBITE, ARAGONITE, MICROLINE, AUGITE, and QUARTZ, with minor and trace concentrations. The samples were also analyzed for concentrations of U-238, Th-232 series, U-235, and K-40 by HPGe gamma spectrometer. The activity concentrations in Bq/kg dry weight of U-238, Ra-226, Th-232, U-235, and K-40 for ten samples from the ground surface are found in the range of 09.43 +/- 0.76 to 18.32 +/- 0.75, 20.26 +/- 0.88 to 31.21 +/- 0.09, 10.32 +/- 0.80 to 20.33 +/- 0.08, 0.783 +/- 0.07 to 0.990 +/- 0.23, and 562.04 +/- 0.62 to 1804.63 +/- 0.45 with mean values of 14.22 +/- 0.65, 23.77 +/- 0.30, 14.00 +/- 0.45, 0.763 +/- 0.11, and 968.19 +/- 0.14 Bq/kg respectively. Also, for ten samples at 0.50 m depth, the activity concentrations in Bq/kg dry weight ranged from 10.27 +/- 0.27 to 25.31 +/- 0.05, 17.96 +/- 0.04 to 30.78 +/- 0.04, 10.74 +/- 0.15 to 28.02 +/- 0.16, 0.570 +/- 0.14 to 1.320 +/- 0.24, and 367.45 +/- 0.65 to 1855.72 +/- 0.71 with mean values of 17.01 +/- 0.15, 24.34 +/- 0.12, 17.30 +/- 0.15, 0.911 +/- 0.19, 934.45 +/- 0.61 Bq/kg respectively. The radium equivalent activity Bq/kg varied from 081.60 to182.29 Bq/kg with mean values 118.33 Bq/kg for the samples on the ground surface, and from 071.77 to 196.96 Bq/kg with mean value 120.40 Bq/kg, for the samples at o.50m depth. The Absorbed Dose Rate (nGy/h), Annual Effective Dose (mSvy/h), External Hazard Index for the ground surface samples ranged from 40.06 to 93.15, 0.049 to 0.114, and 0.220 to 0.492 with mean values 59.13, 0.073, and 0.320, while for the samples at o.50m depth the values ranged from 34.75 to 99.85, 0.043 to 0.123, and 0.194 to 0.532 with mean values 59.67, 0.073, and 0.325. These calculated values were lower than the estimated world -averaged values.