Assessment of Radiation Exposure Level from Some Scrap Metal Dumpsites in Nasarawa State, Nigeria

In this study, the radiation exposure rate emanating from the scrap metals dumpsite was assessed using an Interceptor Spectroscopic personal radiation detector (SPRD). Sixteen (16) scrap metal dumpsites were selected at random across four Local Government Areas (Nasarawa, Lafia, Akwanga, and Keffi) of Nasarawa State, Nigeria. The gamma activity level in µrem/hr on three (3) randomly selected points on each of the scrap metal dumpsites was determined. A reading was taken on point 100 m away from each of the scrap metal dumpsite. Results show that the highest annual effective dose equivalent was observed in Akwanga (AKW4) scrap metal dumpsite with an annual effective dose equivalent of 0.2167 mSv/yr. The scrap metal dumpsite with the lowest annual effective dose equivalent was observed in Lafia (LAF3) and (LAF4) with an annual effective dose equivalent of 0.0613 mSv/yr. The excess lifetime cancer risk of 0.7585 × 10-3 was the highest value recorded in AKW4, while the lowest value was found to be 0.2146 × 10-3 in LAF3 and LAF4. The control radiation exposure level, 100 m from scrap metal dumpsites, shows the value of gamma activity level and annual effective dose equivalent obtained is ranged between 13 µrem/hr and 0.1594 mSv/yr respectively on location KEF1 to 3 µrem/hr and 0.0368 mSv/yr on locations LAF2 and LAF3 respectively. The annual effective dose equivalent values obtained were below the ICRP dose limit of 1 mSv/yr, indicating that, the environments around these scrap metal dumpsites are safe. The excess lifetime cancer risk value (ELCR) obtained in some locations is higher than the world average value of 0.29 × 10-3. Therefore, we recommend that scavengers, workers at the scrap dumpsites are to minimise the period of their stay within the dumpsites, and also the residential homes are to maintain a distance of 500 meters around the scrap metal dumpsites so as to minimise the risk of developing any health problem relating to cancer in future.