Dependence of natural radioactivity on physico-chemical parameters of soils in Belagavi region of Karnataka, India

Abstract

The radiation level, radionuclide distribution, and dependence of radioactivity on physico-chemical parameters of soils have been studied in Belagavi region of Karnataka, India. The gamma dose rates in air were measured using a portable survey metre, and the activity in soils was measured using NaI (Tl)-based gamma ray spectrometer. The measured absorbed dose rate in air ranges from 54 to 77 nGy h⁻¹ with a mean value of 58 nGy h⁻¹. The ⁴⁰K activity in soil was found to vary from 97.9 to 378.5 Bq kg⁻¹ with an average of 214.2 Bq kg⁻¹. The ²²⁶Ra activity varied from 15.3 to 68.8 Bq kg⁻¹ with an average value of 30.5 Bq kg⁻¹ and the activity of ²³²Th varied from 12.3 to 65.4 Bq kg⁻¹ with an average value of 27.96 Bq kg⁻¹. The activity of ²²⁶Ra and ²³²Th were found to be higher than the world average value in some locations of the study area. A good positive correlation was observed between the activity concentration of radionuclides and physico-chemical parameters of soil. A good positive correlation was observed between the activity of ²²⁶Ra and ²³²Th with clay with a correlation coefficient of r = 0.609 and 0.591, respectively. The frequency distribution curve of ²²⁶Ra, ²³²Th, and ⁴⁰K are lognormal in nature. The application of cluster analysis and principal component analysis were carried out using IBM SPSS software for better understanding of dynamics of soil matrix and the dependence of soil radioactivity on the physico-chemical parameters of the soil.

Keywords:

• Natural radionuclides
• soil parameters
• physico-chemical parameter
• cluster analysis and principal component analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The financial support received from the DST-FIST, Govt. of India to develop the laboratory facilities is acknowledged.