Assessment of soil-gas radon concentration over lithologies: a case study from district Karak, Khyber Pakhtunkhwa, Pakistan.

The current study is aimed to determine the variation of soil-gas radon concentrations over different rock formations representing diverse lithologies in the district of Karak, Khyber Pakhtunkhwa, Pakistan. The stratigraphic units were grouped on the basis of lithological contents into four categories, i.e., limestone, evaporites, claystone/mudstone, and sandstone. The highest average soil-gas 222Rn concentration (544 Bq/L) was found in the uranium-bearing Dhok Pathan Formation of the Pliocene age, while the lowest radon levels (0.15 Bq/L) were observed in the salt-bearing strata of Bahadurkhel Salt of Eocene age showing the non-uraniferous nature of the salt. High radon potential associated with the Dhok Pathan Formation is likely to be related to the high degree of uranium mineralization which is contributing to the elevated soil-gas radon levels. The study revealed that the soil-gas radon concentration in all lithologies is varying in the order of RnSandstone > RnLimestone > RnClaystone/Mudstone > RnEvaporites with the highest radon levels in the sandstone unit of uranium-bearing Dhok Pathan Formation. High fluctuations of soil-gas radon levels observed in this study evidently show that lithology and uranium mineralization have strong control over the 222Rn concentrations.

Investigation of Radon Sources, Health Hazard and Risks assessment for children using analytical and geospatial techniques in District Bannu (Pakistan).

PURPOSE: Radon (Rn) is a radioactive, odorless, and colorless gas which has a half-life of 3.83 days. One of the main sources of Rn which is directly consumed by the population is Groundwater (Tube well, Bore well, Hand pump). Rn gas is found naturally in rock, soil and water and can be considered as main health risk factor in terms of lung cancer, stomach diseases, leukemia and childhood cancer. The objective of this study was to determine the concentration of Rn in the drinking water sources, appraisal of health risk for children in District Bannu, Pakistan. MATERIAL AND METHOD: Total of 98 drinking water samples were analyzed by using RAD-7 detector. The experimental data was statistically analyzed by using Pearson's test. The experimental and epidemiological data of the study area are shown on map using ArcGIS version 10.5. RESULTS: The analytical results show that Rn in drinking water was found varying from 10.1 Bq/l to 53.1 Bq/l with the average highest and lowest depth of 60 ft to 550 ft respectively. Pearson's test was used to show the concentration of Rn verses the depth of the water sources so +1 positive linear correlation was observed among the depth of water sources and the concentration of Rn. Out of 98 drinking water samples 40 sample were above the maximum contaminant level of 11.1 Bq/l (MCL) set by WHO, 2002. The effective doses (AED and DEing) for children ranges from 0.00001 to 3.792 mSv/y which exceeds the Permissible Exposure Limit (PEL) of Rn (0.1mSv/y) in 30 drinking water samples . On the basis of analytical results Rn high concentration areas are shown on the map using IDW model of interpolation and health risks were shown in areas where Rn content was above the maximum contaminant level. High correlations of diseases related to Rn were observed amongst the residence of the study area. Gastrointestinal diseases, brain tumor, lung cancer and kidney diseases were observed among the children of the study area. CONCLUSION: From the overall analysis it was observed that high Rn concentration in drinking water may cause substantial health damage in children after long term exposure.

Radon concentration in drinking water and soil after the September 24, 2019, Mw 5.8 earthquake, Mirpur, Azad Jammu, and Kashmir: an evaluation for potential risk.

Radon (222Rn), a radioactive gas resulted from the natural decay of other radioactive elements, pose a threat to the exposed human population. Radon gas emits along the seismically active faults and increased the 222Rn contamination in sorrounding water and soil. This study investigated the concentration of 222Rn in drinking water and soil after the September 24, 2019, Mw 5.8 earthquake, Mirpur District, Azad Jammu, and Kashmir (AJK). For this purpose, water (n = 24) samples were collected from the bore wells of orderly located houses and soil field sampling (n = 12) along with the NE-SW directions of fracture in the Mirpur District. Determined 222Rn in drinking water surpassed the maximum contamination level (MCL, 11.1 kBq/m3) set by the US Environmental Protection Agency (US EPA) in 83%, 50%, and 33% of the sampling point at the site I, site II, and site III, respectively. However, that of soil 222Rn concentration was observed with the normal range (10-50 kBq/m3). Potential exposure of 222Rn consumption in drinking water was the mean effective dose through ingestion (EWing, 0.003 ± < 0.001 mSv/a), the effective dose for inhalation (EWInh, 0.038 ± 0.002 mSv/a), and the total effective dose of human (EWT, 0.041 ± 0.002 mSv/a). Exposure values along with the rupture showed multifold higher risk values (up to 4 times) compared to background sites. These values were observed within the limits (0.1 mSv/a) set by World Health Organization (WHO); however, surpassed the thresholds of the United Nations Scientific Committee on the effects of atomic radiations (UNSCEAR) for all exposure pathways. This study concluded that groundwater in the close vicinity should be avoided or boiled before used for drinking purposes.

Self-assembled three-dimensional reduced graphene oxide-based hydrogel for highly efficient and facile removal of pharmaceutical compounds from aqueous solution.

Herein, self-assembled three-dimensional reduced graphene oxide (RGO)-based hydrogels were synthesized and characterized in detail. A thorough investigation on the uptake of three widely used pharmaceutical drugs, viz. Naproxen (NPX), Ibuprofen (IBP) and Diclofenac (DFC) was carried out from aqueous solutions. To ensure the sustainability of developed hydrogel assembly, practically important parameters such as desorption, recyclability and applicability to real samples were also evaluated. Using the developed 3D hydrogels as adsorptive platforms, excellent decontamination for the above mentioned persistent pharmaceutical drugs was achieved in acidic pH with a removal efficiency in the range of 70-80%. These hydrogels showed fast adsorption kinetics and experimental findings were fitted to different kinetic models, such as pseudo-first order, pseudo-second order, intra-particle and the Elovich models in an attempt to better understand the adsorption kinetics. Furthermore, equilibrium adsorption data was fitted to the Langmuir and Freundlich models, where relatively higher R2 values obtained in case of former one suggested that monolayer adsorption played an important part in drug uptake. Thermodynamic aspects were also studied and negative ΔG0 values obtained indicated the spontaneous nature of adsorption process. The study was also extended to check practical utility of as-prepared hydrogels by spiking real aqueous samples with drug solution, where high % recoveries obtained for NPX, IBP and DFC were of particular importance with regard to prospective application in wastewater treatment systems. We advocate RGO-based hydrogels as environmentally benign, readily recoverable/recyclable material with excellent adsorption capacity for application in wastewater purification.

Potentially toxic elements in soil of the Khyber Pakhtunkhwa province and Tribal areas, Pakistan: evaluation for human and ecological risk assessment.

Potentially toxic elements (PTEs) contaminations in the soil ecosystem are considered as extremely hazardous due to toxicity, persistence and bioaccumulative nature. Therefore, this study was aimed to summarize the results of published PTEs in soil of Khyber Pakhtunkhwa and Tribal areas, Pakistan. Results were evaluated for the pollution quantification factors, including contamination factor (CF), pollution load index (PLI), ecological risk index (ERI) and human health risk assessment. The highest CF (797) and PLI (7.35) values were observed for Fe and ERI (857) values for Cd. Soil PTEs concentrations were used to calculate the human exposure for the risk assessment, including chronic or non-carcinogenic risks such as the hazard quotient (HQ) and carcinogenic or cancer risk (CR). The values of HQ were > 1 for the Cd, Co and Cr in Khyber Pakhtunkhwa and Tribal areas. Tribal areas showed higher values of ERI, HQ, and CR as compared to the Khyber Pakhtunkhwa that were attributed to the mining activities, weathering and erosion of mafic and ultramafic bedrocks hosting ophiolites. This study strongly recommends that best control measures need to be taken for soil PTEs with the intent to alleviate any continuing potential threat to the human health, property and environment, which otherwise could enter ecosystem and ultimately the living beings. Further studies are recommended to combat the soil PTEs concentrations and toxicity in the Tribal areas for a best picture of understanding the element effects on human, and environment can be achieved that will lead to a sustainable ecological harmony.

Arsenic and heavy metals contamination, risk assessment and their source in drinking water of the Mardan District, Khyber Pakhtunkhwa, Pakistan.

The present study was conducted to investigate the physico-chemical characteristics in drinking water of Mardan District, Pakistan. Furthermore, water quality was evaluated for the risk assessment of arsenic and heavy metals (HMs) and their contamination sources. Representative groundwater samples of shallow and deep sources were collected in the study area. These samples were analyzed for physical parameters, anions, light metals (LMs) and HMs. Results were compared with the drinking water guideline values set by the World Health Organization and the US Environmental Protection Agency. Average concentrations of anions, LMs and HMs were found within the maximum allowable contaminant levels except for bicarbonates, Fe, Cu, and Pb. Results revealed that hazard quotients >1 were observed for shallow groundwater for 10% samples only, suggesting potential health risk from water consumption. Correlation analysis and principal component analysis showed a relationship among various physico-chemical parameters in both shallow and deep groundwater. Statistical analyses suggested the geogenic and anthropogenic sources for possible enhancement of various physico-chemical parameters in the aquifer system of the study area.