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Arsenicosis and fluorosis have become severe health hazards associated with the drinking of Arsenic (As) and Fluoride (F-) contaminated groundwater across south-east Asia. Although, significant As and F- concentration is reported from major Himalayan river basins but, the hydrogeochemical processes and mechanisms controlling their contrasting co-occurrence in groundwater is still poorly explored and understood. In the present study, groundwater samples were collected from phreatic and confined aquifers of Upper Indus Basin (UIB), India to understand the hydrogeochemical processes controlling the distribution and co-occurrence of geogenic As and F- in this complex aquifer system. Generally, the groundwater is circum-neutral to alkaline with Na+-HCO3-, Ca2+-Na+-HCO3- and Ca2+-Mg2+-HCO3- water facies signifying the dominance of silicate and carbonate dissolution. The poor correlation of As and F- in groundwater depicted that these geogenic elements have discrete sources of origin with distinct mechanisms controlling their distribution. As enrichment in groundwater is associated with high pH, Fe, Mn and NH4-N suggesting dominance of metal oxide/hydroxide reduction with organic matter degradation. However, F- enrichment in groundwater is associated with high pH, HCO3- and Na+, which is assisted by the incessant dissolution of fluorinated minerals. The study also revealed that high HCO3- facilitates the exchange of hydroxides (OH-) with As and F- on sediment surfaces that contribute to As and F- enrichment in groundwater through desorption. 70% groundwater samples have As and F- concentration above the permissible limit given by WHO. Therefore, continuous exposure to these contaminants may pose severe health hazard of arsenicosis and fluorosis to people living in the region and downstream. The study provides insights into geological sources, hydrogeochemical processes and mechanisms controlling distribution of As and F- in groundwater that will help in developing the appropriate measures to mitigate the impact these contaminants on human health.
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Objectives: Palliative care deals with patients who are facing problems of life-threatening diseases. Under the Ayushman Bharat programme, a new cadre of Community Health Officers (CHOs) is provisioned at Health and Wellness Centres (HWCs) who are nursing graduates. Being the team leader at the HWC level, having a low level of knowledge of palliative care would compromise their service. The study assessed the knowledge of CHOs about palliative care services in a rural district of Purba Medinipur, West Bengal, India. Materials and Methods: A descriptive study with a cross-sectional design was carried out among 314 CHOs posted in different HWCs of Purba Medinipur, West Bengal, during July-August' 2022. We used to collect data based on questionnaires of 'Palliative-Care-Knowledge Questionnaire-Basic' comprising items related to palliative care, the requirement of palliative care, pain management, communication, and dealing with psychosocial issues. A chi-square test was performed to check the association with educational- and experience-related variables and knowledge. Results: Overall, adequate knowledge was present in 216 (68.8%) and inadequate knowledge in 98 (31.2%) of CHOs. Improper knowledge was present regarding the role of oxygen supplementation in dying patients, the need for palliative care in human immunodeficiency virus/acquired immunodeficiency syndrome, chronic non-malignant diseases, pain management, and communication about the prognosis of disease. The proportion of CHOs who had adequate knowledge who were highly educated (70%) and those who had previous job as CHO (73.3%). Almost similar knowledge scores were found among those who ever cared for or never cared for either terminally ill patients (P = 0.89) or cancer patients (P = 0.853). Conclusion: In-depth knowledge was lacking among the CHOs. Training and re-training of CHOs to develop technical and communication skills will help them deliver proper palliative care.
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Elevated groundwater salinity is unsuitable for drinking and harmful to crop production. Thus, it is crucial to determine groundwater salinity distribution, especially where drinking and agricultural water requirements are largely supported by groundwater. This study used field observation (n = 20,994)-based machine learning models to determine the probabilistic distribution of elevated groundwater salinity (electrical conductivity as a proxy, >2000 µS/cm) at 1 km2 across parts of India for near groundwater-table conditions. The final predictions were made by using the best-performing random forest model. The validation performance also demonstrated the robustness of the model (with 77% accuracy). About 29% of the study area (including 25% of entire cropland areas) was estimated to have elevated salinity, dominantly in northwestern and peninsular India. Also, parts of the northwestern and southeastern coasts, adjoining the Arabian Sea and the Bay of Bengal, were assessed with elevated salinity. The climate was delineated as the dominant factor influencing groundwater salinity occurrence, followed by distance from the coast, geology (lithology), and depth of groundwater. Consequently, â¼330 million people, including â¼109 million coastal populations, were estimated to be potentially exposed to elevated groundwater salinity through groundwater-sourced drinking water, thus substantially limiting clean water access.
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Água Potável , Água Subterrânea , Poluentes Químicos da Água , Humanos , Monitoramento Ambiental , Salinidade , Índia , Poluentes Químicos da Água/análiseRESUMO
Different property enhancement techniques have already been established to support upcycling of construction and demolition waste as aggregate in concrete. However, the most suitable and sustainable method is still unknown. Quality improvement of recycled coarse aggregate (RCA) after any treatment method and its environmental impact is estimated using life cycle analysis (LCA). This article compares the environmental impacts of such treatment methods on RCA and aims to find out the most suitable method with minimum impacts. The functional unit of this study is considered the preparation of 1 tonne of treated aggregate (recycled), considering reduction in water absorption after the treatment. An LCA is carried out using the SimaPro software (https://simapro.com/) followed by ISO 14040/44 guidelines. Based on the LCA environmental profiles, thermal treatment is the highest emission contributing removal method followed by mechanical grinding. In strengthening of attached mortar methods, accelerated carbonation process is the major emission contributing method followed by a specific microbial treatment. Moreover, a sensitivity analysis was performed by varying the energy mix with a focus on renewable-based energy mix. The sensitivity analysis shows a shift on selection for the suitable treatment method and other possibilities considering renewable-based energy mix. A preliminary assessment and probable impact prediction could be conceptualized before the adoption of any treatment method on RCA for a particular location.
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Reciclagem , Água , Animais , Estágios do Ciclo de VidaRESUMO
Background: Identiï¬cation of emotional facial expressions (EFEs) is important in interpersonal communication. Six 'universal' EFEs are known, though accuracy of their identiï¬cation varies. EFEs involve anatomical changes in certain regions of the face, especially eyes and mouth. But whether other areas of the face are just as important in their identiï¬cation is still debated. This study was conducted to compare the accuracy of identiï¬cation of universal EFEs under full-face and partial face conditions (only showing the eyes and the mouth regions). Methods: An analytical cross-sectional study was conducted among 140 young Indian adults. They were divided into two equal groups and shown the six universal EFEs in two sets, one with full-face images, and the other with images showing just the eyes and the mouth regions on a computer screen. The participants were asked to identify each of the EFE and their responses were analyzed. Results: Mean age was 21.3 1.7 years for full face group, and 21.2 1.6 years for the partial face group. Most were men, from rural areas and from upper socioeconomic status families, and many of them were students. EFE identiï¬cation was signiï¬cantly higher for part-face group compared to full-face group (p-value .0007). Participants of both groups identiï¬ed happiness the best (100%). For other EFEs, part-face images were identiï¬ed more accurately than full-face images, except for disgust. These diï¬erences were statistically signiï¬cant except for anger and fear. Conclusions: Among young Indian adults, accuracy of identiï¬cation of universal EFEs was high, which was signiï¬cantly enhanced for all except disgust, when only combinations of eyes and mouth were shown, suggesting that other facial regions serve as distractors in EFE identiï¬cation. Key Messages: 1. Identiï¬cation of universal EFEs was higher from partial faces (combination of eyes and mouth) as compared to full-face EFEs for all emotions except disgust. 2. This suggests that other regions of face serve as potential distractors in the identiï¬cation of emotions, except for disgust, where these regions provide more information.
Antecedentes: La identiï¬cación de las expresiones faciales emocionales (EFEs) es importante en la comunicación interpersonal. Se conocen seis EFEs "universales", aunque la precisión de su identiï¬cación varía. Los EFEs involucran cambios anatómicos en ciertas regiones del rostro, especialmente los ojos y la boca. Sin embargo, todavía se debate si la identiï¬cación de las otras áreas del rostro es igualmente importante. Este estudio se llevó a cabo para comparar la precisión de la identiï¬cación de los EFEs universales en condiciones de rostro completo y rostro parcial, mostrando solo las regiones de los ojos y la boca. Método: Se llevó a cabo un estudio analítico transversal entre 140 adultos jóvenes indios. Fueron divididos en dos grupos iguales y se les mostraron los seis EFEs universales en dos conjuntos, uno con imágenes de rostro completo y otro con imágenes que mostraban solo las regiones de los ojos y la boca. A los participantes se les pidió que identiï¬caran cada uno de los EFE y sus respuestas fueron analizadas. Resultados: La edad promedio fue de 21.3 1.7 años para el grupo de rostro completo y de 21.2 1.6 años para el grupo de rostro parcial. La mayoría de los participantes eran hombres, provenían de áreas rurales, pertenecían a familias de nivel socioeconómico alto y eran estudiantes. La identiï¬cación de EFEs fue signiï¬cativamente mayor en el grupo de rostro parcial en comparación con el grupo de rostro completo (p = .0007). Los participantes de ambos grupos identiï¬caron mejor la felicidad (100%). Para los demás EFEs, las imágenes de rostro parcial se identiï¬caron con mayor precisión que las imágenes de rostro completo, excepto en el caso del asco. Estas diferencias fueron estadísticamente signiï¬cativas, excepto en los casos de ira y miedo. Conclusiones: Entre los adultos jóvenes indios, la precisión en la identiï¬cación de EFEs universales fue alta, lo cual se mejoró signiï¬cativamente para todos, excepto el asco, cuando solo se mostraron combinaciones de ojos y boca. Esto sugiere que otras regiones faciales actúan como distractores en la identiï¬cación de EFEs.
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Although geogenic Arsenic (As) contamination is well-recognized in northern Chile, it is not restricted to this part of the country, as the geological conditions favoring As release to the human environment exist across the country as well, although not at the same level, based on comparatively fewer studies in central and southern Chile. The present work provides a critical evaluation of As sources, pathways, and controls with reports and case studies from across the country based on an exhaustive bibliographic review of its reported geogenic sources and processes that affect its occurrence, systematization, and critical revision of this information. Arc magmatism and associated geothermal activities, identified as the primary As sources, are present across the Chilean Andes, except for the Pampean Flat Slab and Patagonian Volcanic Gap. Metal sulfide ore zones, extending from the country's far north to the south-central part, are the second most important geogenic As source. While natural leaching of As-rich mineral deposits contaminates the water in contact, associated mining, and metallurgical activities result in additional As release into the human environment through mining waste and tailings. Moreover, crustal thickness has been suggested as a principal controlling factor for As release, whose southward decrease has been correlated with lower As values.
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BACKGROUND: Evidence linking arsenic in drinking water to digestive tract cancers is limited. We evaluated the association between arsenic levels in groundwater and gallbladder cancer risk in a case-control study (2019-2021) of long-term residents (≥10years) in two arsenic-impacted and high gallbladder cancer risk states of India-Assam and Bihar. METHODS: We recruited men and women aged 30 to 69 years from hospitals (73.4% women), with newly diagnosed, biopsy-confirmed gallbladder cancer (N = 214) and unrelated controls frequency-matched for 5-year age, sex, and state (N = 166). Long-term residential history, lifestyle factors, family history, socio-demographics, and physical measurements were collected. Average-weighted arsenic concentration (AwAC) was extrapolated from district-level groundwater monitoring data (2017-2018) and residential history. We evaluated gallbladder cancer risk for tertiles of AwAC (µg/L) in multivariable logistic regression models adjusted for important confounders [Range: 0-448.39; median (interquartile range), T1-0.45 (0.0-1.19); T2-3.75 (2.83-7.38); T3-17.6 (12.34-20.54)]. RESULTS: We observed a dose-response increase in gallbladder cancer risk based on AwAC tertiles [OR = 2.00 (95% confidence interval, 1.05-3.79) and 2.43 (1.30-4.54); Ptrend = 0.007]. Participants in the highest AwAC tertile consumed more tubewell water (67.7% vs. 27.9%) and reported more sediments (37.9% vs. 18.7%) with unsatisfactory color, odor, and taste (49.2% vs. 25.0%) than those in the lowest tertile. CONCLUSIONS: These findings suggest chronic arsenic exposure in drinking water at low-moderate levels may be a potential risk factor for gallbladder cancer. IMPACT: Risk factors for gallbladder cancer, a lethal digestive tract cancer, are not fully understood. Data from arsenic-endemic regions of India, with a high incidence of gallbladder cancer, may offer unique insights. Tackling 'arsenic pollution' may help reduce the burden of several health outcomes.
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Arsênio , Água Potável , Neoplasias da Vesícula Biliar , Poluentes Químicos da Água , Masculino , Humanos , Feminino , Água Potável/análise , Estudos de Casos e Controles , Exposição Ambiental , Índia/epidemiologiaRESUMO
Elevated fluoride in groundwater is a severe problem in India due to its extensive occurrence and detrimental health impacts on the large population that thrives on groundwater. Although fluoride is primarily a geogenic pollutant, existing model-based studies lack the amalgamation of the influence of geologic factors, specifically tectonics, for identifying groundwater fluoride distribution. This drawback encourages the present study to investigate the association of the tectonic framework with fluoride in a multi-model approach. We have applied three machine learning models (random forest, boosted regression tree, and logistic regression) to predict elevated groundwater fluoride based on fluoride measurements across India. The random forest model outperformed other models with an accuracy of 93%. Tectonics was found to be one of the most important predictors alongside "depth to water table." Two major areas of high risk identified were the northwest parts and the south-southeast cratonic peninsular region. The random forest model also performed significantly well over the validation dataset. We estimate that nearly 257 million people are exposed to elevated fluoride risk in India. We endeavor that the findings of our study would be an effective tool for identifying the areas at risk of elevated fluoride and also assist in undertaking effective groundwater management strategies.
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Água Subterrânea , Poluentes Químicos da Água , Humanos , Fluoretos/análise , Poluentes Químicos da Água/análise , Índia , Geologia , Monitoramento AmbientalRESUMO
The role of submarine groundwater discharge (SGD) in transporting terrestrial-sourced arsenic (As) to the global oceans is not well documented. In the present study, executed on a coast adjoining the extensive groundwater As-contaminated Ganges river delta, we hypothesize that As-enriched groundwater discharges to the adjoining Bay of Bengal (BoB) through SGD flow paths. We conducted high-resolution, field-based investigations and thermodynamic modeling to understand the SGD-sourced As discharge and geochemical cycling of As and other redox-sensitive solutes along the discharge path under varying redox conditions and water sediment interactions. The As distribution and other solutes were measured in a series of multi-depth observation wells and sediment cores, extending from the high tide line (HTL) to 100 m toward the sea, for pre- and post-monsoon seasons. Results reveal the presence of a plume carrying up to 30 µg/L dissolved load of As toward the sea. Arsenic is associated with a plume of Fe and exhibits similar shore-perpendicular variability. Arsenic distribution and transport is controlled by the Fe-Mn redox cycle and influenced by terrestrial groundwater discharge. Field-observations and geochemical modeling demonstrate that Fe-hydroxide precipitates in the subterranean estuary and acts as an interim sink for As , which is eventually mobilized on alteration of geochemical conditions with the season. Fluctuating plume size can be attributed to seasonal variation in fresh groundwater input to the site. Estimates indicate up to 55mg/m2/d As is released to BoB from the site. Based on physicochemical observations this study demonstrates the yet to be studied SGD derived As cycles and the role of SGD dynamics in controlling the fate of redox-sensitive contaminants and their discharge into global oceans.
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Arsênio , Água Subterrânea , Arsênio/análise , Rios , Oceanos e Mares , Água , Monitoramento Ambiental/métodos , Água do MarRESUMO
Background: Appropriateness of admissions and inpatient length of stay (LOS) are important factors controlling health-care expenditure. The current study was conducted to assess the proportion of appropriate admissions among 29-day to 12-year--old aged patients admitted to pediatric wards of a tertiary health-care center in one month and evaluate inappropriate LOS among them. Materials and Methods: An observational longitudinal study was carried out for two months among patients admitted to the pediatric inpatient department using Pediatric Appropriateness Evaluation Protocol (PAEP)-II tool. All patients admitted to the institution during the study period were included in the study. Results: Among 495 children, 438 (88.5%) were appropriately admitted. Inappropriate admission was mostly found in children aged 1 to 5 years (29, 16.6%), those who lived >5 km from the hospital (45, 15.2%), and those who presented with other systemic illnesses (13, 31.7%). Among the appropriately admitted children, 333 (76%) met the criteria of appropriate LOS during their hospital stays. Multivariable logistic regression showed that the age of the children (AOR = 0.99; 95% CI = 0.98, 0.99), age-appropriate feeding (AOR = 2.12;95% CI = 1.30,3.47), and hematological disorder (AOR = 0.16; 95% CI = 0.05, 0.52) were found to be associated with the children being kept at the hospital inappropriately. Conclusions: The current study observed a high proportion of appropriate admission in children. However, a higher proportion of inappropriate LOS among them was seen. The younger age group, age-appropriate feeding, and type of illness were found as the primary predictors for inappropriate LOS.
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BACKGROUND: The Workload Indicators of Staffing Need (WISN) human resource planning and management tool developed by Shipp (1998) and popularized by the World Health Organization gives health managers a way to analyze and calculate correct staffing levels in health facilities. OBJECTIVES: This study aimed to assess the current workload and staffing need of staff nurses for rural hospitals in Darjeeling district, West Bengal. MATERIALS AND METHODS: Primary data were collected by interviews with nursing personnel using a semi-structured interview schedule. Secondary data were obtained from available records at the rural hospitals. Workload components were established for health service activities, support activities, and additional activities. Staffing needs based on workload was calculated after adjusting allowance multiplier. RESULTS: WISN findings highlighted varying degrees of health worker shortages and inequities in their distribution at different health facilities. WISN ratio indicated that the work pressure of health staff was highest at Kharibari RH (0.45), followed by Naxalbari RH (0.54). About 43% of nurses' time was occupied with support activities, instead of nursing care. CONCLUSIONS: WISN method can help policy-makers in optimizing utilization of existing human resources. There is a need to adopt flexible health workforce planning and recruitment policy to manage the patient load and disease burden.
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Hospitais Rurais , Recursos Humanos de Enfermagem Hospitalar , Admissão e Escalonamento de Pessoal , Carga de Trabalho , Humanos , Índia , Carga de Trabalho/estatística & dados numéricos , Recursos Humanos de Enfermagem Hospitalar/provisão & distribuição , Organização Mundial da Saúde , Entrevistas como Assunto , Recursos HumanosRESUMO
Introduction: Exposure to high levels of noise is a problem among tea factory workers worldwide, but it is poorly studied in India. Aims: This study aimed to assess noise generation in various parts of a black tea factory and find out prevalence of occupational noise-induced hearing loss (ONIHL) and its determinants among employees. Materials and Methods: An observational cross-sectional study was performed in a black tea processing factory of Darjeeling District. Noise levels and exposure data at different parts of the factory were measured using a sound level meter. Participant characteristics were obtained using a questionnaire and noise-induced hearing loss data obtained by audiometry. A sound map was generated based on noise exposure data and a multivariable logistic regression performed to assess determinants of ONIHL. Results: Sound pressure levels ranged from 58.7 to 90.3 dBA, with the highest levels in the crushing-tearing-curling (CTC) room. Noise exposure of workers was the highest during curling process and the lowest during packaging in the packing room. The prevalence of ONIHL was found to be 28.3%, most of which were of moderate degree, and the highest prevalence was among CTC room workers. Multivariable analysis showed significant association only between daily noise exposure and the presence of ONIHL (AOR 1.68, P value = 0.018). None of the study participants used any hearing protection equipment during work. Conclusions: Generation of high levels of noise is a pertinent problem in the black tea factory, which, coupled with non-use of personal protective equipment, led to a high risk and prevalence of ONIHL.
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Non-destructive evaluation using ultrasonic pulse velocity (Vp) testing has extensive applications in the concrete industry. With advances in construction technology, the use of ground granulated blast furnace slag (GGBFS) as a partial replacement to cement in a concrete mix is growing in popularity primarily because it reduces the initial capital cost of raw materials and the associated energy costs. This paper investigates the effect of the water-to-cement (wc) ratio and the cement content replaced by GGBFS on the development with time of the ultimate compressive strength (fc') and the compression wave velocity (Vp) of mortar. The results showed that in the case of mortar with higher percentages of GGBFS replacement (where nucleation surfaces are more abundant), increasing wc can increase fc' but cause a decrease in Vp. The posterior hydration process is highly dependent upon the water particles in the mixture after the first stage of hydration. After 7 days of curing, experimental results show that the fc' of slag blended cement mix design wc ratio of 0.6 surpassed the fc' value of an Ordinary Portland cement. A regression model correlating the fc' and Vp of slag blended mortar is developed, which can be used to predict fc' at concrete ages ranging from 1 day to 28 days for mixes with GGBFS percentage replacement values ranging from 15% to 45%.
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Globally, arsenic (As) contamination is widespread in hydrological systems and the link between As enrichment and regional tectonic and climatic factors is still not well understood in orogenic environments. This work provides new insights on the relationship between As, tectonics, and climate by assessing the hydrochemistry of Chile, an active subduction zone with highly diverse natural settings. Selected study sites include fluvial courses along four regional transects connecting the Chilean coast to the Andes Cordillera in the northern, central, and southern areas of the country. The results indicate that As concentrations in surface water and fluvial sediments show a general positive correlation to crustal thickness and they tend to decrease progressively from northern to southern Chile. In contrast, As concentrations are negatively correlated to average annual precipitation which shows a significant increase toward southern Chile. From a regional tectonic perspective, northern Chile presents greater Andes shortening and higher crustal thicknesses, which induces increased crustal contamination and As content at the surface. Extremely low precipitation rates are also tied to local As enrichment and a sediment-starved trench that might favor higher plate coupling and shortening. On the contrary, decreased shortening of the Andes in southern Chile and related lower crustal thickness induces lower crustal contamination, thus acting as an As-poor provenance for surficial sediments and surface water. High precipitation rates further induce dilution of surface water, potential mobilization from the solid phase, and a significant amount of trench sediments that could induce lower plate coupling and lower shortening. At the local scale, a low potential for As mobilization was found in northern Chile where a greater distribution of As-bearing minerals was observed in sediments, mostly as finer particles (<63 µm). The abundance of Fe-oxides potentially acts as a secondary surficial sink of As under the encountered physicochemical conditions.
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Arsênio , Poluentes Químicos da Água , Arsênio/análise , Sedimentos Geológicos/química , Chile , Monitoramento Ambiental , Água , Poluentes Químicos da Água/análise , MineraisRESUMO
Introduction: During the refining and packing of tea, a very fine dust is formed which is called the tea fluff. Exposure to this fluff has been reported to cause ventilatory defects on chronic exposure. Objective: To determine the association between air quality of the different work sections of tea gardens and the ventilatory functions of the workers. Methodology: An observational analytical study with cross sectional design was conducted on 400 apparently healthy individuals working in different sections of 4 tea gardens. Data on sociodemographic characters of the population, particulate matter (PM) and air quality (AQI) was recorded. All participants underwent spirometric evaluation. Results: The mean (SD) age of the study population was 37.8 (8) years. Most (67%) of the study participants were females. The participants were engaged in the job for a mean (SD) of 4.7 (2.7) years. The median distribution of PM2.5, PM 10 and AQI are progressively higher from the garden section to the dry section. A significant correlation between FVC and PM2.5 and PM10 is seen. FEV1 and FEV1/FVC shows a significant correlation with all air quality parameters while FEF25-75 is correlated to none of them. Comparison of the three models to predict the spirometric variables show that even after adjustments, the FEV1 is significantly associated with air quality parameters, FEV1/FVC is significantly associated with the air quality parameters and age while the FEF25-75% is dependent on the age of the participant. Conclusion: There is a strong correlation between the ventilatory parameters and the cumulative exposure of PM2.5, PM10 and AQI, which persists even after adjustment for confounders.
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Background: Properly constructed single best-answer multiple choice questions (MCQs) or items assess higher-order cognitive processing of Bloom's taxonomy and accurately discriminate between high and low achievers. However, guidelines for writing good test items are rarely followed, leading to generation and application of faulty MCQs. Materials and Methods: During lockdown period in 2020, internal assessment was taken through online mode using Google Forms. There were 60 'single response type' MCQs, each consisting of single stem and four options including one correct answer and three distractors. Each item was analyzed for difficulty index (Dif I), discrimination index (DI), and distractor efficiency (DE). Results: The mean of achieved marks was 42.92± (standard deviation [SD], 5.07). Dif I, DI, and DE were 47.95± (SD 16.39) in percentage, 0.12± (SD 0.10), and 18.42± (SD 15.35), respectively. 46.67% of the items were easy and 21.66% were of acceptable discrimination. Very weak negative correlation was found between Dif I and DI. Out of total 180 distractors, 51.66% were nonfunctional one. Conclusion: Item analysis and storage of MCQs with their indices provides opportunity for an examiner to select MCQs of appropriate difficulty level as per the need of assessment and decide their placement in the question paper.
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Arsenic (As) dynamics within the extensively contaminated aquifers of the Ganges River delta have been widely studied over the past few decades, but the hydrogeochemical signatures across the delta aquifers remain to be characterized. Here, we characterize the varied geochemical and isotopic (δ18O, δ2H) signatures of groundwater across the delta and interpret the hydrogeochemical evolution pathways and the driving processes on a regional-scale as a function of the delta hydrostratigraphy. Our hydrostratigraphic model identifies three major aquifer sub-systems across the delta from north-west to south-east: a single continuous unconfined aquifer (Type I); a semiconfined vertically-segregated aquifer sub-system (Type II); and a nearly confined multilayered aquifer sub-system (Type III). The Type I aquifer is dominated by Ca-Mg-HCO3-rich waters, while the aquifers to the south (Type II and Type III) exhibits increasing dominance of Na-Cl hydrogeochemical facies at shallow and intermediate depths and Na-HCO3 hydrogeochemical facies in the deep aquifers. The spatial distribution of As is also found to be heavily dictated by hydrostratigraphy, wherein the Type I aquifer sub-system yields similar concentrations across depths, while the Type II and Type III aquifer sub-systems exhibit a sharp increase in As-safe aquifers with depth. Although dominant reducing conditions occur within the delta groundwater, co-occurrence of redox-sensitive solutes from varying redox stability fields indicates to the development of overlapping redox zones. Stable isotopic signatures of groundwater exhibit a progressive depletion away from the Bay of Bengal. The Type I aquifer exhibits relatively homogenous hydrogeochemical signatures, possibly suggesting deeper infiltration of recharge under higher vertical hydraulic gradients, while the Type II and Type III aquifers exhibit variability across depth, which is possibly a reflection of horizontally stratified groundwater flows, dictated by the spatial geometry of the intervening aquitard layers.
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Arsênio , Água Subterrânea , Poluentes Químicos da Água , Arsênio/análise , Bangladesh , Monitoramento Ambiental , Água Subterrânea/química , Índia , Rios , Poluentes Químicos da Água/análiseRESUMO
Deep terrestrial subsurface represents a huge repository of global prokaryotic biomass. Given its vastness and importance, microbial life within the deep subsurface continental crust remains under-represented in global studies. We characterize the microbial communities of deep, extreme and oligotrophic realm hosted by crystalline Archaean granitic rocks underneath the Deccan Traps, through sampling via 3000 m deep scientific borehole at Koyna, India through metagenomics, amplicon sequencing and cultivation-based analyses. Gene sequences 16S rRNA (7.37 × 106 ) show considerable bacterial diversity and the existence of a core microbiome (5724 operational taxonomic units conserved out of a total 118,064 OTUs) across the depths. Relative abundance of different taxa of core microbiome varies with depth in response to prevailing lithology and geochemistry. Co-occurrence network analysis and cultivation attempt to elucidate close interactions among autotrophic and organotrophic bacteria. Shotgun metagenomics reveals a major role of autotrophic carbon fixation via the Wood-Ljungdahl pathway and genes responsible for energy and carbon metabolism. Deeper analysis suggests the existence of an 'acetate switch', coordinating biosynthesis and cellular homeostasis. We conclude that the microbial life in the nutrient- and energy-limited deep granitic crust is constrained by the depth and managed by a few core members via a close interplay between autotrophy and organotrophy.
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Metagenômica , Microbiota , Bactérias , Ciclo do Carbono , Índia , Microbiota/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismoRESUMO
The groundwater within the aquifers of the Ganges River delta exhibits significant spatial variability in concentrations of redox-sensitive solutes [e.g., arsenic (As), iron (Fe), manganese (Mn)]. The groundwater As and Mn concentrations show conspicuous contrasting distribution on the opposite banks of the Bhagirathi-Hooghly (B-H) River, the Indian distributary of the Ganges River. Here, we investigate the differences in hydrostratigraphic framework and groundwater evolutionary pathways across the B-H River that might have resulted in such variations. We developed a hydrostratigraphic model for the region and also used inverse reaction-path modeling along three hypothesized end-member flow paths to understand the dominant processes that might control As and Mn cycling within the aquifers. Our results indicate that the variability of As and Mn across the B-H River is a function of a complex interplay between the aquifer architecture, groundwater chemistry, and redox conditions.
Assuntos
Arsênio , Água Subterrânea , Poluentes Químicos da Água , Arsênio/análise , Monitoramento Ambiental , Manganês/análise , Rios , Poluentes Químicos da Água/análiseRESUMO
One of the potential impacts of climate change is enhanced groundwater contamination by geogenic and anthropogenic contaminants. Such impacts should be most evident in areas with high land-use change footprint. Here, we provide a novel documentation of the impact on groundwater nitrate (GWNO3 ) pollution with and without climate change in one of the most intensely groundwater-irrigated areas of South Asia (northwest India) as a consequence of changes in land use and agricultural practices at present and predicted future times. We assessed the probabilistic risk of GWNO3 pollution considering climate changes under two representative concentration pathways (RCPs), i.e., RCP 4.5 and 8.5 for 2030 and 2040, using a machine learning (Random Forest) framework. We also evaluated variations in GWNO3 distribution against a no climate change (NCC) scenario considering 2020 status quo climate conditions. The climate change projections showed that the annual temperatures would rise under both RCPs. The precipitation is predicted to rise by 5% under RCP 8.5 by 2040, while it would decline under RCP 4.5. The predicted scenarios indicate that the areas at high risk of GWNO3 pollution will increase to 49 and 50% in 2030 and 66 and 65% in 2040 under RCP 4.5 and 8.5, respectively. These predictions are higher compared to the NCC condition (43% in 2030 and 60% in 2040). However, the areas at high risk can decrease significantly by 2040 with restricted fertilizer usage, especially under the RCP 8.5 scenario. The risk maps identified the central, south, and southeastern parts of the study area to be at persistent high risk of GWNO3 pollution. The outcomes show that the climate factors may impose a significant influence on the GWNO3 pollution, and if fertilizer inputs and land uses are not managed properly, future climate change scenarios can critically impact the groundwater quality in highly agrarian areas.