Measurement of Radionuclides and their Impact on the Environment Around Asphalt Plants in Delta State

Abstract

Measurement of radionuclides and their impact on the environment around asphalt plants in some selected Asphalt mixing plant within Delta State, Nigeria was carried out. The Background Ionizing Radiation and the GPS of the location was measured using a well calibrated Gamma scout; Geiger counter multi-radiation meter and a GARMIN GPS meter and the result obtained at Raycon, DLA and Neodede Hot Asphalt Mixing Plants for outdoor exposure, shows a total mean value of (0.01492±0.038) (mRh-1), (0.01497±0.037) (mRh-1) and (0.01413±0.014) (mRh-1) respectively. The total mean values obtained in the selected radiological centers were all above the world average BIR level of 0.013 (mR?-1) as recommended by UNSCEAR (2000). These results were used to calculate some hazard indices such as the Equivalent dose (ED) in mSv??1, the absorbed dose rate (ADR) in nGy??1, Annual Effective Dose Equivalent (AEDE) and Excess Life Cancer Risk (ELCR). All the values obtained for each Parameter were above the world permissible limits as given by UNSCEAR (2000). The average activity concentration of 40K, 238U and 232Th in the soil of the three study areas were (603.21±30.94) Bq/Kg, (5.70 ±0.678) Bq/Kg and (6.91 ± 0.405) Bq/Kg. For 40K the average activity concentration was high and above the world recommended limit of 420 Bq/Kg (UNSCEAR 2000). 238U and 232Th were below the world recommended limits which are 33 Bq/Kg and 45 Bq/Kg. respectively. The Activity Concentration results were used to calculate the following radiological parameters: Absorbed gamma dose rate (DR) in (nGy/h), Annual Effective Dose Equivalent AEDE in (?Svy-1), the Radium Equivalent (Raeq), Excess Life Cancer Risk (ELCR) and External Hazard Index. All the calculated radiological Values were above the recommended limit given by (UNSCEAR 2000). Water samples in the study areas was also collected and the average activi