A study of transfer factor of radio nuclides from soil to plant.

number: 
741
English
department: 
Degree: 
Imprint: 
Physics
Author: 
Zainab Khalid Nassir Allah Al-Ani
Supervisor: 
Dr.Nada F. Tawfiq
Dr. Laith A. Al-Ani
year: 
2003
Abstract:

In the present work, an attempt has been made to study the uranium concentration and the transfer factor from soil to plant using fission track method and gamma spectroscopic method. Our present investigation is based on the study of a pair of 10 samples collected from ten different sites in Baghdad city. Ten of them represents the plant samples collected from the ten different sites, the other ten samples represents the soil samples belonging to the plant samples collected from the corresponding sites. In fission track method, soil samples [0.5 g] were pressed into a pellet of [2 cm] diameter and [1.5 mm] thickness. The pellet was covered with Small strips of CR- 39 polycarbonate track detector on both sides and enclosed in aluminum capsules. The pellet placed in a plate of paraffin wax at a distance of [5 cm] from the Am-Be neutron source with flux (5 x 103 n/cm².s). CR-39 was etched at temperature of 60°C for [4 hr] using NaOH. The etched detectors were analyzed under optical microscope. The same procedure is applied with the plant samples. The results obtained show that the uranium concentration varies from 0.478 to 1.45 ppm and from 0.136 to 1.539 ppm in soil and plant respectively. In gamma spectroscopy method, we collected a sufficient number of samples of plants [verdure] in some locations simultaneously with the soil samples. All the spectrums are calibrated with respect of Cs-137 and Co-60 radioactive source The gamma energy lines 662,1167, 969, 1120 were used to represent Cs-137, Cs-134, Th-232, and Ra-226 respectively From the experimental analysis, it is observed that the uranium content in various plant and soil species varies from (0.53 to 33.25 Bq/Kg) and from (2.05 to 81.27 Bq/Kg) respectively. Based on the radioactive concentrations of the radio nuclides in the soil samples, all the results obtained are within the international levels as given by UNSCAR (United Nations Scientific Committee on the effect of Atomic Radiation) data. The results of the transfer factor show that the transfer factor different from sample to other, this result can be justifiable due to the nature (type) the soil and due to the type of the plant samples.