Measurement of environmental radioactivity for estimation of radiation exposure from saline soil of Lahore, Pakistan

Abstract

Radioactivity, natural and man made, is omnipresent in the earth's crust in different amounts. The soil on the earth's crust is a source of continuous exposure to human beings. The amount of radioactivity in soil depends upon the type of soil and its uses. The soil of barren area should show different amount of radioactivity when compared with that of the cultivated soil. For the investigation of amount of radioactivity in the barren soil, an area of about 60 h of saline soil was selected in Rakh Dera Chal near the city of Lahore in the Punjab province of Pakistan. The technique of gamma ray spectrometry was applied using high purity germanium gamma-ray detector and a PC based MCA. Activity concentration levels due to 40 K, 137 Cs, 226 Ra and 232 Th were measured in 125 saline soil samples collected at a spacing of about 4 ha at the depth level of 0– 25 cm with a step of 5 cm depth. Activity concentrations of the concerned radionuclides were as follows: 40 K , 524.84– 601.62 Bq kg −1 , 137 Cs , not detected (less than the lower detection limit), 226 Ra , 24.73– 28.17 Bq kg −1 , and 232 Th , 45.46– 52.61 Bq kg −1 . 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 soil samples.