Vol.:(0123456789) 1 3 Environmental Earth Sciences (2020) 79:4 https://doi.org/10.1007/s12665-019-8765-3 ORIGINAL ARTICLE Radiometric and petrographic characterization of sediment samples collected from Jhelum, Neelum and Kunhar Rivers of Muzafarabad, Azad Kashmir Muhammad Rafque 1  · Kimberlee Jane Kearfott 2  · Abdul Jabbar 3  · Abdul Razzaq Khan 1  · Said Rahman 4  · Muhammad Saleem Mughal 5 Received: 14 February 2019 / Accepted: 29 November 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract In the present study, we present results of radiometric and petrographic analyses of sediment samples collected from the river banks of Jhelum, Neelum, and Kunhar confuencing in the district Muzafarabad. Gamma activity concentrations due to 226 Ra, 232 Th, and 40 K were determined using high-purity germanium detector (HPGe). For a total of thirty sediment samples collected from three rivers, the activity concentrations of 226 Ra, 232 Th and 40 K varied from 03.32 ± 0.40 to 100.45 ± 2.08 Bq Kg −1 , 02.17 ± 1.35 to 298.42 ± 4.50 Bq Kg −1 and 37.88 ± 11.66 to 1386.32 ± 30.17 Bq Kg −1 with mean values of 36.91 ± 1.12, 61.57 ± 2.81 and 557.33 ± 19.81 Bq Kg −1 , respectively. The overall value of Ra eq for all the investigated sediment samples was found to be in the range from 9.34 ± 3.23 to 633.53 ± 10.14 Bq Kg −1 with mean value of 167.88 ± 6.66 Bq Kg −1 . The values estimated for hazard indices, viz., external hazard index (H ex ), internal hazard index (H in ), representative index (I r ), gamma index (I) and alpha index (I α ) for all sediment samples were found to be in the range from 0.02 ± 0.008 to 1.71 ± 0.03, 0.034 ± 0.009 to 1.98 ± 0.03, 0.07 ± 0.02 to 4.57 ± 0.07, 0.03 ± 0.01 to 2.29 ± 0.03 and 0.02 ± 0.002 to 0.50 ± 0.010 with mean values of 0.45 ± 0.02, 0.55 ± 0.02, 1.23 ± 0.04, 0.62 ± 0.02 and 0.18 ± 0.010, respectively. The activity concentrations were subsequently used to estimate the terrestrial gamma ray absorbed dose rate in air at 1 m above the ground and annual efec- tive dose. For all the samples, the values of gamma absorbed dose rate and annual efective dose ranged from 4.42 ± 1.49 to 284.24 ± 4.64 nGyh −1 and 0.027 ± 0.009 to 1.74 ± 0.03 mSv year −1 with mean values of 77.49 ± 3.04 nGyh −1 and 0.48 ± 0.02 mSv year −1 , respectively. Mean gamma absorbed dose rate computed in the present study is higher than that reported for world average (59 nGy h −1 ) and it also exceeds the UNSCEAR proposed safe limit of 55 nGyh −1 . The resulting annual efective dose is also higher than the worldwide average value of 0.07 mSv year −1 , however, it is less than the safe limit of 1 mSv year −1 . From the present study, it is concluded that there is a possibility of high radiation risk from the sediments of the surveyed rivers due to elevated activity concentrations and doses when used as building materials. The building codes need to be revisited taking into account the efects of radiation exposure and absorbed dose on the inhabitants. Keywords Gamma activity · Radiation hazards · Absorbed dose · Annual efective dose · River sediments · Azad Kashmir * Muhammad Rafque mrafque@gmail.com; mrafque@ajku.edu.pk 1 Department of Physics, University of Azad Jammu and Kashmir, Muzafarbad 13100, Azad Kashmir, Pakistan 2 Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109-2104, USA 3 Health Physics Division, Pakistan Institute of Nuclear Science and Engineering (PINSTECH), Nilore, Islamabad 45650, Pakistan 4 Pakistan Space and Upper Atmosphere Research Commission (SUPARCO), P.O. Box 8402, Of University Road, Karachi 75270, Pakistan 5 Institute of Geology, University of Azad Jammu and Kashmir, Muzafarabad, Pakistan