Natural environmental radioactivity and estimation of radiation exposure from saline soils

• Published in: International journal of environmental science and technology (Tehran) Vol. 1; no. 4
• Main Author: N. Akhtar, M. Tufail and M. Ashraf
• Format: Journal Article
• Language: English
• Published: Center for Environment and Energy Research and Studies (CEERS) 14-12-2006
• Subjects: Saline soil, virgin soil, fertilized soil, HPGe detector, gamma spectrometry, environmental radioactivity, 40K, 137Cs, 226Ra, 232Th
• ISSN: 1735-1472

The study was conducted for the investigation of amount of
radioactivity in the barren and cultivated soil of Bio saline Research
Station in Pakka Anna, established by Nuclear Institute for Agriculture
and Biology (NIAB) in 1990, 34 km. away from the city of Faisalabad, in
the Punjab province of Pakistan. The studies were done on an area of
about 100 hectares of two types of virgin and fertilized saline soils.
The technique of gamma ray spectrometry was applied using HPGe (high
purity germanium) gamma ray detector and a PC based MCA. Activity
concentration levels due to 40K, 137Cs, 226Ra and 232Th were measured
in 250 saline soil samples collected at a spacing of about 4 hectares
at the depth level of 0-25 cm. with a step of 5 cm. depth.
Activity concentrations ranges of the concerned radionuclides for both
of the soils were as follows: 40K, for virgin and cultivated saline
soil was 500−610.2 and Bq/kg 560.2−635.6 respectively;
137Cs, 3.57−3.63 and 1.98−5.15 Bq/kg 238U, 26.3−31.6
and 30.3−38.7 Bq/kg, and 232Th, 50.6−55.3 and
50.6−64.0 Bq/kg respectively. The absorbed dose rate in air lies
in the region 63-73 nGyh-1 and 68-83 nGyh-1 for virgin and fertilized
soils respectively. This indicates that this region lies in the area of
higher radiation background, while comparing with the worlds'
average. The slightly higher value of dose in the fertilized farm may
be due to the use of fertilizers for cultivation. Before the
radiometric measurements, chemical analysis for concentration of Na, Ca
and Mg was also carried out along with the measurement of electrical
conductivity and pH of the soil samples.