Assessment of radiological hazard of NORM in Margalla Hills limestone, Pakistan

Studies on naturally occurring radioactive material (NORM) in the limestone from the Margalla Hills have been carried out by measuring gamma activity and to access its radiological implications if any. For data acquisition, a High-Purity Germanium detector was employed. The activity concentrations of (226)Ra, (232)Th, and (40)K were found to be 14.32?±?0.24, 2.05?±?0.04, and 13.80?±?0.20 Bq kg(-1), respectively. These values are relatively lower as compared to that in the limestone of other countries and much lower than the values reported for the natural building stones. The average specific activities due to (226)Ra were found to be higher when compared with (40)K and (232)Th. Indices of radium equivalent activity (Ra(eq)), internal hazard (H(in)), indoor absorbed gamma dose rate (D(R,)), and corresponding annual effective dose (E(eff)) were also determined for the limestone-made rooms. All of these indices were found to be in the lower ranges. The Margalla Hills limestone does not pose any excessive radiological health hazard as a building material and in industrial uses for a common man.     

Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid

In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min^?1. The uranium complex was removed from the resin by 0.1 mol dm^?3 HCl at flow rate of 3.2 mL min^?1 and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm^?3 HCl, 3.2 mL min^?1) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L^?1, a relative standard deviation (RSD) of 0.8 % at 100 μg L^?1, enrichment factor of 30, and a sample throughput of 42 h^?1, whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L^?1, a RSD of 1.32 % at 10 μg L^?1, enrichment factor of 150, and a sampling frequency of 11 h^?1 were reported.     

Non-linear relationship between tourism,economic growth,urbanization, and environmental degradation: evidence from smooth transition models

Environmental Science and Pollution Research - The study aims to analyze two objectives: first is to explore the non-linear relationship between tourism development, economic growth, urbanization,...     

Propolis efficacy on SARS-COV viruses: a review on antimicrobial activities and molecular simulations

Environmental Science and Pollution Research - This current study review provides a brief review of a natural bee product known as propolis and its relevance toward combating SARS-CoV viruses....     

Proteomics of mercury-induced responses and resilience in plants: a review

Environmental Chemistry Letters - Excessive levels of heavy metals in the environment induce toxic effects on food crops and human health. For instance, mercury (Hg) disrupts global plant...