Determination of Radon and Thoron Activity in the Soil By using Solid StateNuclear Track Detectors (SSNTDs), Passive Technique

Radon and thoron activity concentration levels have been determined in the soil of Basra Governorate, Iraq. The area of the study included three districts, they are Hayy-Alabas, Hayy-Aljameeat and Almuaficia.. In this investigation CR-39 and LR-115 type2 solid state nuclear track detectors and a cylindrical plastic container technique are used. The samples are taken from the surface and the depth 1m for each location. Maximum activity of radon levels observed is (16200 Bq.m-3) in Hayy-Alabas station number 10 for soil from the surface and minimum levels is (1560 Bq.m-3) were observed in Almuaficia station number 54 for soil from the surface. The activity of radon were measured in Hayy-Aljameeat and Almuaficia which are with in normal limits according to International Commission on Radiological Protection (ICRP). The high values of radon activity are measured in many locations in Hayy-Alabas and Hayy-Aljameeat. There are many anomalous values of radon activity in the soil in some stations of Hayy-Alabas has been observed in this study. The reasons of this anomalous has been discussed. The activity concentration of thoron is smaller than the activity concentration for radon (( 220 / 222 c c A A ) <1) over all study area. The reason of this result has been discussed. The average value of the activity of thoron concentration 220 c A in the soil samples from the surface equal 2073.33 Bq.m-3, 1893.75 Bq.m-3 and 1822.22 Bq.m-3 for Hayy-Alabas, Hayy-Aljameeat and Almuaficia respectively and the average value for the soil samples from the depth 1m equal 1666.66 Bq.m-3 , 906.25 Bq.m-3 and 1103.333 Bq.m-3 for Hayy-Alabas, Hayy-Aljameeat and Almuaficia respectively.