| Abstrakt: |
The study is aimed at measuring the background ionizing radiation (BIR), the absorbed dose rate (ADR), the annual effective dose (AED) and excessive lifetime cancer risk (ELCR) at four sites in the Aniocha South local government area (LGA) of Delta State, denoted as A to D. The study was performed using a calibrated Geiger-Muller (GM) detector (Radiation Alert Inspector) as well as a geographic positioning system (GPS) to determine the longitude and latitude of each site. The average (range) outdoor BIR, ADR, and AED were 0.021 ± 0.01 (0.01 to 0.04) mR.hr-1, 181.6 ± 77.7 (60.9 to 322.8) nGy.hr-1, and 0.22 ± 0.10 (0.07 to 0.40) mSv.yr-1, respectively. Among the processing sites, the average AED for granite, bitumen, and staff residential areas were 0.31, 0.12, and 0.17 mSv.yr-1, while surface measurements at the "burnt stone" had the highest AED (0.41 mSv.yr-1). ADR and AED were both considerably higher than the world average of 59 nGy.hr-1 and 0.07 mSv.yr-1. The average effective lifetime cancer risk (ELCR) was 7.7 × 10-4 (1 in 1,300), with the highest in the granites. The ELCR risk grade was high (> 10-4), suggesting that remedial action be taken to ensure safety in the granite sites based on the environmental protection agency (EPA) United States report. [ABSTRACT FROM AUTHOR] |
