ASSESSMENT OF RADIOACTIVITY CONCENTRATION IN SOIL OF SOME MINING AREAS IN CENTRAL NASARAWA STATE, NIGERIA

摘要

A study was conducted to determine 226Ra, 232Th, and 40K natural? activity? concentrations? in? surface? soils/sediments? of some? mining? areas? in? Central? Nasarawa? State? Nigeria,? using Sodium? Iodide-Thallium? Gamma? Spectroscopy.? Seven? major sites were? identified? from the highly mining areas? of the zone and a total of twenty? (21) samples were collected throughout the whole accessible areas. From the analyzed samples, mean natural activity concentrations were determined and the results show 403.963±7.29 Bq/kg, 32.52±4.65 Bq/kg and 56.23±2.30 Bq/kg? for? 40K,? 226Ra? and? 232Th? respectively.? The? results obtained were a bit lower compare to the World average value, except for 232Th which is higher than the World average value with a difference of 20.23? Bq/kg.? The evaluated annual mean effective? dose? is? 0.04±2.7? mSv/yr.? This? is? far? less? than? the annual dose limit for members of the public. The mean Radium equivalent? activity? is? 141.56±7.2Bqkg- 1.? The? average background radiation absorbed doses at the two spots are 5.81 ±0.08 mSv/y and 8.45±0.56 mSv/y. This is higher compare to worldwide? average? of? 1mSvy-1? given? by? IAEA? (1996)? and UNSCEAR (2000). This implies that the people near the mining sites are likely to receive little or no? radiation? dose when? the stay outside or inside their houses.