Evaluation of Radiation Hazard Indices for Selected Dumpsites in Port Harcourt, Rivers State, Nigeria

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Author(s) Avwiri, G. O. | Olatubosun, S. A. | Ononugbu, C. P.
Pages 663-673
Volume 3
Issue 10
Date October, 2014
Keywords Radioactivity, Dumpsites, Gamma Spectrometry, Specific Activity, Absorbed Dose, Effective Dose, Radiation Hazard Indices

Activity concentration of soil samples from selected dumpsites within Port Harcourt, Rivers State, Nigeria was determined. These dumpsites are recipients of municipal waste from different sources. Two soil samples each from ten selected dumpsites were collected. Gamma Spectrometry analysis was carried out to determine specific activity using NaI(Tl) scintillation detector. The activity concentrations of the soil samples obtained with gamma spectroscopy ranged from 32.21 Bq/Kg to 100.10 Bq/kg for 232Th, 29.16 Bq/Kg to 61.18 Bq/Kg for 238U and 222.15 Bq/Kg to 1166.99 Bq/Kg for 40K. The equivalent radiation exposure for the locations ranged from 0.50 mSv/yr to 1.08 mSv/yr with nine of the locations having values below the permissible threshold of 1.0 mSv/yr for soil. Furthermore, Annual Gonadal Equivalent Dose (AGED) values are above the permissible threshold of 300 mSv/yr for the locations. Four of the hazard indices; Excess Lifetime Cancer Risk (ELCR), Annual Effective Dose Equivalent, AEDE (outdoor and indoor) and Activity Concentration Index (ACI) are below the world permissible limits for most locations while that of few locations are higher due to high specific activity of the radionuclides. The remaining indices, external hazard index (Hex), internal hazard index (Hin) and radium equivalent activity (Raeq) are below permissible limits of 1.0, 1.0 and 370 Bq/Kg respectively. The results were compared with previous works as well as world standards and correlate with those reported for similar environment in Nigeria. Generally, radiation burden and associated risk posed by municipal waste to the studied environment and scavengers is minimal.

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