Distribution of natural radionuclides and associated geological properties in shelf sediment of Southwest (SW) Bay of Bengal: A multivariate statistical approach

Abstract

Forty-three marine shelf sediment samples from the southwest (SW) Bay of Bengal were analyzed to understand the spatial distribution of natural radionuclides with their associated geological properties and evaluate these parameters through multivariate statistical techniques. The study is important to assess and evaluate the radiation level of the coastal environment. The distribution of the ²²⁶Ra activity varied from BDL to 49.0 Bq kg⁻¹ with an average of 9.79 Bq kg⁻¹, ²³²Th activity varied from 3.93 to 148 Bq kg⁻¹ with an average value of 39.74 Bq kg⁻¹, and ⁴⁰K activity varied from 149 to 879 Bq kg⁻¹ with an average value of 360.03 Bq kg⁻¹. The results show that the average radioactive concentrations of radionuclides were less than suggested by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) ranges. The radiological indices for coastal shelf sediments were evaluated. The average value of the Radium Equivalent (Ra_eq) was 94.35 Bq kg⁻¹, the Absorbed Dose Rate (ADR) was 43.65 nGy h⁻¹, and the Annual Effective Dose (AEDE) was 53.53 µSv y⁻¹. These averages were compared to international threshold limits and were below the recommended criteria. The correlation matrix, hierarchical clustering, and factor analysis using multivariate statistics were employed to investigate the relationships between natural radionuclides, radiological parameters, and geological properties. Additionally, a contour map was provided as a visual representation of the spatial distribution of radiological and geological contents within the study area.