ASSESSMENT OF RADIOACTIVITY CONCENTRATION IN SOIL OF SOME MINING AREAS IN CENTRAL NASARAWA STATE, NIGERIA
Abstract
A study was conducted to determine 226Ra, 232Th, and 40Knatural 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.
