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We present the results of groundwater quality assessment that was done during the rainy season in November 2018 in the Manga region of Nyamira County, Kenya. Water samples were collected from three springs, Kiangoso, Kerongo, and Tetema, for the assessment. Water quality index was calculated based on pH, turbidity, nitrate, phosphate, calcium, magnesium, chloride, sulphates, fluoride, iron, total phosphorous, total hardness, total alkalinity, total dissolved solids, and total coliform. These fifteen parameters were analyzed and characterized according to standard methods and with reference to the World Health Organization and Kenya Bureau of Standards for physiochemical and bacteriological parameters which were then used in the calculation of water quality index. The water quality index was 21.32 for Kiangoso, 29.66 for Kerongo, and 25.64 for Tetema. The water quality index was found to be of excellent quality status at Kiangoso, while of good quality status at Kerongo and Tetema. The water quality index of Manga groundwater represented by the three springs therefore is less than 30 and can be used for drinking, irrigation, and industrial purpose. The present results are crucial for future management of groundwater in the Manga region., Competing Interests: The authors declare that there are no conflicts of interest., (Copyright © 2022 Alice Makonjo Wekesa and Calford Otieno.)

We present results on the first principle study of the elastic constants and the phonon dispersion of EuFe 2 As 2 at zero pressure. The ground-state energy calculations were performed within Density Functional Theory (DFT) and the generalized gradient approximation using the pseudopotential method with plane-wave basis sets. The projector augmented-wave (PAW) pseudopotentials were used in our calculation. The open source code QUANTUM ESPRESSSO was used with its pseudopotential database. The study on the elastic constants at zero pressure was a clear indication that the compound is mechanically stable, and the phonon dispersion study also indicated that the compound is dynamically stable. The elastic constants and mechanical properties also led to the conclusion that the compound is ductile and anisotropic., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 N. K. Omboga et al.)

Construction sand is naturally polluted with radionuclides of terrestrial origin. In this study, specific activities of 238 U, 232 Th, and 40 K in 30 sand samples collected along the Ekalakala River, Machakos County, Kenya, were measured using a high-purity germanium γ -ray spectrometer. The specific activities ranged between 9.7 Bqkg -1 and 24.0 Bqkg -1 , 11.5 Bqkg -1 and 26.2 Bqkg -1 , and 820 Bqkg -1 and 1850 Bqkg -1 for 238 U, 232 Th, and 40 K, respectively. While the mean specific activities for 238 U and 232 Th were less than half of the world average values of 33 Bqkg -1 and 45 Bqkg -1 , respectively, the average specific activity of 40 K was significant since it was three times the global mean value of 420 Bqkg -1 . A calculated absorbed radiation dose rate for the sand varied between 46.8 nGyh -1 and 94.2 nGyh -1 with a mean of 68.5 ± 13.3 nGyh -1 . This is not significantly different from the world average dose rate of 60 nGyh -1 for geological samples. The AEDR and H ex had maximum values of 0.29 mSvy -1 and 0.52, respectively, both within the recommended limits of radiation exposure for members of the general public. Based on these results, the sand from Ekalakala River does not pose significant health implication to the sand harvesters as well as the inhabitants of the houses constructed using this sand., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Lucia Nyiva Munyao et al.)