Radiological and pollution risk assessments of terrestrial radionuclides and heavy metals in a mineralized zone of the siwalik region (India).

The present study reveals the distribution of terrestrial radionuclides (226Ra, 232Th and 40K) and heavy metals (Cr, Ni, Cu, Zn, Pb, Co) from soil samples of Una, Hamirpur and Kangra districts of Himachal Pradesh (India). The 226Ra, 232Th, 40K activity concentration in the studied region has been varied from 8 to 3593 Bq kg−1; 21–370 Bq kg-116; 62–7130 Bq kg−1 respectively. High disequilibrium factor (238U/226Ra) depicts that uranium constantly migrates from clay oxidizing zone and getting precipitated with enrichment towards south. An attempt has been made to correlate the distribution of these radionuclides and heavy metals with geology and rock type formation of Siwalik region. The concentration of Pb, Zn and Co was found higher than Indian average background value. Multiple radiological and pollution indices have been estimated for proper risk analysis in the studied region. The annual effective dose in studied region is lower than the recommended limit of 1.0 mSv a−1. The obtained geo-accumulation index and enrichment factor indicated that the sites located in the Hamirpur and Kangra regions were moderately contaminated with Pb and Co. The Nemerow pollution index and contamination security index suggested that almost 45% sites were slightly to moderately polluted. The non-carcinogenic and carcinogenic risks for both children and adults were within acceptable limits. • 218 samples from 33 locations in a uranium-mineralized area of Siwaliks were studied for radiological and pollution risk assessment. • Concentrations and distributions of radionuclides and heavy metals were correlated with sediment physico-chemical parameters. • Majority of radiation hazard indices were above the world average value. • Non-carcinogenic and carcinogenic risks for both children and adults were below EPA threshold limits. • Spatial distributions of radionuclides and heavy metals indicated precipitation towards south of the clay oxidizing zone. [ABSTRACT FROM AUTHOR]