Radiological Implication Of Rn-222 Concentrations In Waters From Quarries Environs, Correlation With Ra-226 Concentrations And Rocks Geochemistry

Radon concentration in ground and surface waters collected from the environs of quarries was assessed using advanced Durridge RAD-7 analyser with RAD H2O accessory. Mean radon concentration varied from 55.41 to 104.45 Bq l(-1) and 61.48 to 119.71 Bq l(-1) for boreholes and wells waters samples. The average radon activities ranged from 47.31 to 111.90 Bq l(-1) and 42.22 to 88.22 Bq l(-1) for ponds and streams, respectively. The majority of the sources investigated (82%) showed mean radon values below the World Health Organization (WHO) maximum contaminant level of 100 Bq l(-1). All the water samples (100%) exceeded the Environmental Protection Agency (EPA) maximum contaminant level of 11.1 Bq l(-1) and 4-40 Bq l(-1) prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Gamma spectrometry quantitative assessment of radioelements revealed the weighted mean concentration range of 105.88 (migmatite) to 612.64 Bq kg(-1) (migmatite), 10.32 (migmatite) to 67.23 Bq kg(-1) (porphyritic granite), and 10.02 (migmatite) to 79.18 Bq kg(-1) (porphyritic granite) for K-40, U-238(Ra-226), and Th-232, respectively. However, it was observed that high values of Rn-222 concentrations in water are associated with low activity concentrations of Ra-226 in the rocks, an indication of low water-rock interaction. Chemical analysis of rocks using AAS revealed SiO2, Al2O3, Fe2O3, MgO, CaO, K2O, TiO2, P2O5, and MnO as major oxides. The elemental composition revealed that migmatite, porphyritic granite, and charnockite are in alkali-calcic and calcic-alkali series, while undifferentiated schist was of calcic series.