Environmental Earth Sciences

Storage and distribution of organic carbon in cave sediments: examples from two caves in the northern karst region of Puerto Rico
Downey AR, Riddell JL, Padilla IY and Vesper DJ
The clastic sediments that accumulate in cave settings can be an important storage reservoir for organic carbon. This study reports on grain size, total organic carbon (TOC) concentrations, and total organic carbon:total organic nitrogen (TOC:TON) ratios measured in sediments from two caves in Puerto Rico. El Tallonal Cave (TAL) is a small cave with a flowing stream; the sediments in TAL were collected from a deposit that is being actively eroded. Clara Cave (CAM) is an upper level of the Río Camuy Cave System; the sediments from CAM were newly deposited by an internal river that rose in response to Hurricane Maria. Sediments collected from both caves were poorly sorted and contained no apparent stratigraphic correlation. CAM sediments contained a larger range in TOC concentrations but were overall lower than TOC in the TAL sediments. In TAL, the TOC concentrations were higher in sediments collected from below the erosional terrace. TOC:TON ratios from sediments at both caves were highly variable, highlighting the heterogeneous deposition and storage of organic matter. Despite the observed variation, TOC concentrations in both cave systems could cause retardation of organic contaminants by up to two orders-of-magnitude, implying that deposited sediments influence the fate of organic contaminants in the groundwater; therefore, cave sediments could facilitate long term storage of organic carbon and associated contaminants.
Earth system models for regional environmental management of red tide: Prospects and limitations of current generation models and next generation development
Elshall AS, Ye M, Kranz SA, Harrington J, Yang X, Wan Y and Maltrud M
Earth system models (ESMs) serve as a unique research infrastructure for quality climate services, yet their application for environmental management at regional scale has not yet been fully explored. The unprecedented resolution and model fidelity of the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations, especially of the High-Resolution Model Intercomparison Project (HighResMIP) focusing on regional phenomena, offer opportunities for such applications. This article presents the first venture into using the HighResMIP simulations to tackle a regional environmental issue, the Florida Red Tide. This is a harmful algae bloom caused by the dinoflagellate a toxic single-celled microscopic protist. We use CMIP6 historical simulations to establish a causal agreement between the position of Loop Current, a warm ocean current that moves into the Gulf of Mexico, and the occurrence of blooms on the Western Florida shelf. Results show that the high-resolution ESMs are capable of simulating the phenomena of interest (i.e., Loop Current) at the regional spatial scale with generally adequate data-model agreement in the context of the relation between Loop Current and red tide. We use this case study to elaborate on the prospects and limitations of using publicly available CMIP data for regional environmental management. We highlight the current gaps and the developmental needs for the next generation ESMs, and discuss the role of stakeholder participation in future ESMs development to facilitate the translation of scientific understanding to better inform decision-making of regional environmental management.
Mediation of arsenic mobility by organic matter in mining-impacted sediment from sub-Arctic lakes: implications for environmental monitoring in a warming climate
Miller CB, Parsons MB, Jamieson HE, Ardakani OH, Patterson RT and Galloway JM
Arsenic (As) is commonly sequestered at the sediment-water interface (SWI) in mining-impacted lakes through adsorption and/or co-precipitation with authigenic iron (Fe)-(oxy)hydroxides or sulfides. The results of this study demonstrate that the accumulation of organic matter (OM) in near-surface sediments also influences the mobility and fate of As in sub-Arctic lakes. Sediment gravity cores, sediment grab samples, and porewaters were collected from three lakes downstream of the former Tundra gold mine, Northwest Territories, Canada. Analysis of sediment using combined micro-X-ray fluorescence/diffraction, K-edge X-ray Absorption Near-Edge Structure (XANES), and organic petrography shows that As is associated with both aquatic (benthic and planktonic alginate) and terrestrially derived OM (e.g., cutinite, funginite). Most As is hosted by fine-grained Fe-(oxy)hydroxides or sulfide minerals (e.g., goethite, orpiment, lepidocrocite, and mackinawite); however, grain-scale synchrotron-based analysis shows that As is also associated with amorphous OM. Mixed As oxidation states in porewater (median = 62% As (V), 18% As (III);  = 20) and sediment (median = 80% As (-I) and (III), 20% As (V);  = 9) indicate the presence of variable redox conditions in the near-surface sediment and suggest that post-depositional remobilization of As has occurred. Detailed characterization of As-bearing OM at and below the SWI suggests that OM plays an important role in stabilizing redox-sensitive authigenic minerals and associated As. Based on these findings, it is expected that increased concentrations of labile OM will drive post-depositional surface enrichment of As in mining-impacted lakes and may increase or decrease As flux from sediments to overlying surface waters.
Sustainable water resources development and management in large river basins: an introduction
Li P, Wang D, Li W and Liu L
Water resources are important in large basins which are important places for human habitation and industrial and agricultural development. The background of editing this thematic issue was introduced and the general water resources situation and water quality status in four major large river basins in the Asian and African continents were briefly summarized to give readers general pictures of water resources development and management in these basins, and these large river basins are the Yellow River Basin, the Yangtze River Basin, the Indus Basin, and the Nile Basin. The thematic issue papers were classified into four clustered topical categories, and the main points of the papers in this thematic issue were summarized. Finally, the perspectives of future sustainable water resources development and management in large river basins were proposed.
Study of climatology parameters on COVID-19 outbreak in Jordan
Hamdan M, Dabbour L and Abdelhafez E
To control the spread of COVID-19 disease and reduce its mortality, an early and precise diagnose of this disease is of significant importance. Emerging research data show that the current COVID-19 pandemic may be affected by environmental conditions. Therefore, the impact of weather parameters on COVID-19 distribution should be explored to predict its development in the next few months. This research aims to study the association between the daily confirmed COVID-19 cases in the three major cities of Jordan; Amman, Zarqa, and Irbid and climate indicators to include the average daily temperature (°C), wind speed (m/s), relative humidity (%), pressure (kPa), and the concentration of four pollutants (CO, NO, PM and SO). The data were obtained from the World Air Quality Project website and the Jordanian Ministry of Environment. A total of 305 samples for each city was used to conduct the data analysis using multiple linear regression and a feedforward artificial neural network. It was concluded that the multiple linear regression and feedforward artificial neural network could forecast the COVID-19 confirmed cases in the case studies; Amman, Irbid, and Zarqa. Finally, global sensitivity analysis using Sobol analysis indicated that pressure in Amman and Zarqa and the concentration of NO in Irbid has a high rate of positive cases that supports the virus's spread.
Carbon dioxide emissions mitigation strategy through enhanced geothermal systems: western Anatolia, Turkey
Chandrasekharam D and Baba A
Although Turkey is not the biggest GHG polluter, its emissions have increased by 110.4% since 1990. Currently, its CO emissions alone have crossed 400 Mt. Within the scope of 2 °C targets (2D scenario), the country can easily surpass this target test by increasing its renewable energy sources as a primary energy source mix, by developing its Enhanced Geothermal Sources (EGS) locked up in the radiogenic granites of western Anatolia. The radiogenic heat generated by these granites, spread over an area of 4221 sq. km, varies from 5.3 to 16.34 µW/m. Based on the electricity generation capacity of granites from Soultz-sous-Forets and Cooper Basin EGS sites, the combined electricity generation capacity of Kestanbol and Kozak granite plutons is about 830 billion kWh. For the period extending from 2019 to 2023, Turkey is aiming at reducing the usage of gas for electricity generation from 29.9 to 20.7%, increasing the share of renewable energy sources from 32.5 to 38.8%, increasing the electricity production from local energy sources from 150 to 219 TWh and increasing the electricity usage per-capita from 3.7 to 4.3 MWh. These energy targets can be achieved by major contributions from hydrothermal and EGS energy sources. This review demonstrates that besides electricity and heat, EGS energy can be utilized, together with other renewable energy sources, such as hydrothermal, wind, and concentrated solar for providing fresh water through the desalination process. These energy sources would provide food, energy, and water security to the country for several decades.
Characterization of particle size segregation and heterogeneity along the slopes of a waste rock pile using image analysis
Qiu P and Pabst T
Large amounts of waste rock are produced during mining operations and often disposed of in large piles. Particle size segregation usually occurs during waste rock disposal, which can lead to high variations of particle size distribution (PSD) along the pile slope, increasing the risk for hydrogeotechnical instabilities. Determining segregation in situ is, therefore, critical to implement control measures and optimize deposition plans. However, characterizing PSD at field scale remains challenging because of the large dimensions of the pile, the instability of the blocks and the steep slopes. In this study, images, covering a 1400 m wide and 10 m high section of a waste rock pile, were taken and analyzed using image analysis to characterize segregation along the slope of the pile. PSD curves in different sections along the slope were determined and the segregation degree and characteristic diameters (e.g., , , ) were quantitatively compared. Results allowed to quantify segregation along the vertical direction of the pile, showing that segregation degree increased from - 0.77 ± 0.39 in the top (finer zone) to + 0.4 ± 0.14 in the bottom (coarser zone). Significant lateral heterogeneity was also observed with maximum diameters varying between 80 and 180 cm in the bottom section. Such segregation and lateral heterogeneity could induce significant variations of waste rock properties, with, for example, hydraulic conductivities varying by more than 2 orders of magnitude within the pile.
Chamoli disaster: pronounced changes in water quality and flood plains using Sentinel data
Meena SR, Chauhan A, Bhuyan K and Singh RP
The Himalayan rivers are vulnerable to devastating flooding caused by landslides and outbreak of glacial lakes. On 7 February 2021, a deadly disaster occurred near the Rishi Ganga Hydropower Plant in the Rishi Ganga River, killing more than 100 people. During the event, a large volume of debris and broken glacial fragments flooded the Rishi Ganga River and washed away the Rishi Ganga Hydropower plant ongoing project. This study presents the impact of the Chamoli disaster on the water quality of Rishi Ganga River in upstream near Tapovan and Ganga River in downstream near Haridwar through remote sensing data. Five points have been used at different locations across the two study areas and three different indices were used such as Normalized difference water index (NDWI), Normalized difference turbidity Index (NDTI), and Normalized difference chlorophyll index (NDCI), to analyze changes in water quality. Spectral signatures and backscattering coefficients derived from Sentinel-2 Optical and Sentinel-1 Synthetic-aperture radar (SAR) data were also compared to study the changes in water quality. It was evident from the water quality indices and spectral signatures that the flood plains changed significantly. Using spectral signatures and different indices, the water level in the Chilla dam canal near Haridwar was found to decreased after the Chamoli disaster event as the flood gates were closed to stop the deposit of sediments in the canal. Results suggest changes in water quality parameters (turbidity, chlorophyll concentration, NDWI) at the five locations near the deadly site and far away at Haridwar along the Ganga River. This study is a preliminary qualitative analysis showing changes in river flood plain and water quality after the Chamoli disaster.
A new approach to establish safe levels of available metals in soil with respect to potential health hazard of human
Golui D, Datta SP, Dwivedi BS, Meena MC, Ray P and Trivedi VK
Safe levels of extractable pollutant elements in soil have not been universally established. Prediction of metal solubility in polluted soils and the subsequent transfer of these metals from soil pore water to the human food supply via crops are required for effective risk assessment from polluted soils. Thus an attempt has been made to develop a novel approach to protect human health from exposure to toxic metals through assessing risk from metal polluted soils utilised for agriculture. In this study, we assess the relative efficacy of various forms of 'free ion activity model' (FIAM) for predicting the concentration of cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn) and copper (Cu) in spinach and wheat as example crops, thereby providing an assessment of risk to human health from consumption of these crops. Free metal ion activity in soil solution was estimated using the Windermere Humic Aqueous Model VII (WHAM-VII) and the Baker soil test. Approximately 91, 81, 75, 94 and 70% of the variability in Cd, Pb, Ni, Zn and Cu content, respectively, of spinach could be described by a FIAM using an estimate of the free ion activity of the metals provided by WHAM-VII. Owing to the different concentration of ethylenediamine tetraacetic acid (EDTA) and diethylenetriamine pentaacetic acid (DTPA) used in the present experiment, higher prediction coefficients were obtained using EDTA (0.05 M), rather than DTPA (0.005 M), as the metal extractant in an integrated solubility-FIAM model. Out of three formulations, the FIAM, based on free ion activity of metals in soil pore water, determined from solution extracted with samplers, was distinctly superior to the other formulations in predicting metal uptake by spinach and wheat. A safe level of extractable metal in soil was prescribed using a hazard quotient derived from predicted plant metal content and estimated dietary intake of wheat and spinach by a human population.
Mapping potential desertification-prone areas in North-Eastern Algeria using logistic regression model, GIS, and remote sensing techniques
Mihi A, Ghazela R and Wissal D
Desertification is an environmental threat that affects many countries in the world, and it poses specially an ecological issue to Algeria. This study aimed to assess areas sensitive to desertification in North-Eastern Algeria (Tebessa province) using a logistic regression model (LRM), and geomatics-based approaches. Topsoil Grain Size Index (TGSI), Normalized Difference Vegetation Index (NDVI), Aridity index (AI), and Anthropic pressure on the steppe environment (APSE) were selected as desertification indicators for representing land surface conditions from soil, vegetation, climate, and anthropic disruptors. Results indicate that both AI and TGSI are the most crucial indices conditioning desertification risk. Other indices; NDVI and ASPE were appeared as secondary important indices. Herein, although vegetation generally is a key factor for reading desertification, this result shows that vegetation changes in this study are less important than other desertification conditioning parameters. Area under curve value equal 0.94 indicates a satisfactory accuracy for the proposed model. In total, desertification risk changes increasingly along a North-to-South gradient of the whole research area. Besides, slight, moderate, high, and very high classes occupied 0.87%, 21.08%, 19.33% and 58.72% of the total land area, respectively. LRM is recommended as an accurate and easily applied tool to monitor desertification, especially in scarce data environment in developing countries. Additionally, the results obtained in this paper represent a basic scientific tool for implementing current and future policies to control desertification at areas with high risk.
Alluvial fans at Cala Gonone (Sardinia), a fast developing touristic village: origins, hazards and potential risks
Pascucci V, Martini IP and Andreucci S
The study area of Cala Gonone in NE Sardinia (Italy) consists of a wide terraced re-entrance/valley crowned inland by carbonate hills and, near the coast bounded laterally and partly floored by thin basaltic lava lying over carbonate bedrock. In this re-entrance, several inland alluvial fans (500 m length by 700 m wide) have developed, and a local ~ 30 m high, about 10 m wide (thick), 400 m long scarp body-remnant of semi-consolidated alluvial fan deposits is exposed along the coast. The fans experience depositional events mostly developed during the late Pleistocene. They although nowadays dormant may be reactivated by major rainstorms during strong climate changes. In these last few decades, the touristic village of Cala Gonone has been rapidly expanding over the mid to lower parts of two coalescing alluvial fans (Stadium and Gustui) and along the coastal marine scarp edge (Palmasera alluvial fan system). The village thus may become exposed to natural hazards if extreme climatic conditions may re-occur. Moreover, rock falls and the instability of the costal scarp due to wave erosion may add addition hazards for habitations built near the scarp crest and visitors to the frontal replenished beach. As commonly occurring elsewhere since antiquity, the risk perception of such events is low because of the centennial, millennial of longer recurrence. Such perception does not negate the hazards but a long event recurrence may be accepted as a reasonable risk for the human's activity. Nevertheless, serious consideration should be given to potential problems and plan and build for amelioration and defense. The evidence of what environmentally did and could still happen in the Cala Gonone and similar other area is in part clearly imprinted on the landscape: geology, geomorphology, and relative details in the stratigraphy and sedimentology of the deposits.
Microbial‑induced carbonate precipitation (MICP) technology: a review on the fundamentals and engineering applications
Zhang K, Tang CS, Jiang NJ, Pan XH, Liu B, Wang YJ and Shi B
The microbial‑induced carbonate precipitation (MICP), as an emerging biomineralization technology mediated by specific bacteria, has been a popular research focus for scientists and engineers through the previous two decades as an interdisciplinary approach. It provides cutting-edge solutions for various engineering problems emerging in the context of frequent and intense human activities. This paper is aimed at reviewing the fundaments and engineering applications of the MICP technology through existing studies, covering realistic need in geotechnical engineering, construction materials, hydraulic engineering, geological engineering, and environmental engineering. It adds a new perspective on the feasibility and difficulty for field practice. Analysis and discussion within different parts are generally carried out based on specific considerations in each field. MICP may bring comprehensive improvement of static and dynamic characteristics of geomaterials, thus enhancing their bearing capacity and resisting liquefication. It helps produce eco-friendly and durable building materials. MICP is a promising and cost-efficient technology in preserving water resources and subsurface fluid leakage. Piping, internal erosion and surface erosion could also be addressed by this technology. MICP has been proved suitable for stabilizing soils and shows promise in dealing with problematic soils like bentonite and expansive soils. It is also envisaged that this technology may be used to mitigate against impacts of geological hazards such as liquefaction associated with earthquakes. Moreover, global environment issues including fugitive dust, contaminated soil and climate change problems are assumed to be palliated or even removed via the positive effects of this technology. Bioaugmentation, biostimulation, and enzymatic approach are three feasible paths for MICP. Decision makers should choose a compatible, efficient and economical way among them and develop an on-site solution based on engineering conditions. To further decrease the cost and energy consumption of the MICP technology, it is reasonable to make full use of industrial by-products or wastes and non-sterilized media. The prospective direction of this technology is to make construction more intelligent without human intervention, such as autogenous healing. To reach this destination, MICP could be coupled with other techniques like encapsulation and ductile fibers. MICP is undoubtfully a mainstream engineering technology for the future, while ecological balance, environmental impact and industrial applicability should still be cautiously treated in its real practice.
A data-driven approach for modelling Karst spring discharge using transfer function noise models
Rudolph MG, Collenteur RA, Kavousi A, Giese M, Wöhling T, Birk S, Hartmann A and Reimann T
Karst aquifers are important sources of fresh water on a global scale. The hydrological modelling of karst spring discharge, however, still poses a challenge. In this study we apply a transfer function noise (TFN) model in combination with a bucket-type recharge model to simulate karst spring discharge. The application of the noise model for the residual series has the advantage that it is more consistent with assumptions for optimization such as homoscedasticity and independence. In an earlier hydrological modeling study, named Karst Modeling Challenge (KMC; Jeannin et al., J Hydrol 600:126-508, 2021), several modelling approaches were compared for the Milandre Karst System in Switzerland. This serves as a benchmark and we apply the TFN model to KMC data, subsequently comparing the results to other models. Using different data-model-combinations, the most promising data-model-combination is identified in a three-step least-squares calibration. To quantify uncertainty, the Bayesian approach of Markov-chain Monte Carlo (MCMC) sampling is subsequently used with uniform priors for the previously identified best data-model combination. The MCMC maximum likelihood solution is used to simulate spring discharge for a previously unseen testing period, indicating a superior performance compared to all other models in the KMC. It is found that the model gives a physically feasible representation of the system, which is supported by field measurements. While the TFN model simulated rising limbs and flood recession especially well, medium and baseflow conditions were not represented as accurately. The TFN approach poses a well-performing data-driven alternative to other approaches that should be considered in future studies.
Coulomb stress analysis for several filling and operational scenarios at the Grand Ethiopian Renaissance Dam impoundment
Madson A and Sheng Y
Increased demand for power generation coupled with changing seasonal water uncertainty has caused a worldwide increase in the construction of large hydrologic engineering structures. That said, the soon-to-be-completed Grand Ethiopian Renaissance Dam (GERD) will impound the Blue Nile River in Western Ethiopia and its reservoir will encompass ~ 1763 km and store ~ 67 Gt (km) of surface water. The impoundment will undergo maximum seasonal load changes of ~ 28 to ~ 36 Gt during projected seasonal hydroelectric operations. The GERD impoundment will cause significant subsurficial stresses, and could possibly trigger seismicity in the region. This study examines Coulomb stress and hydrologic load centroid movements for several GERD impoundment and operational scenarios. The maximum subsurficial Coulomb stress applied on optimally oriented fault planes from the full impoundment is ~ 186 kPa and over 30% of our model domain incurs Coulomb stresses ≥ 10 kPa, regardless of the impoundment period length. The main driver behind Coulomb stress and load centroid motion during impoundment is the annual, accumulated daily reservoir storage change. The maximum Coulomb stresses from the highest amplitude season of five long-term operational scenarios are around 36, 33, 29, 41, and 24% of the total maximum stresses from the entire GERD impoundment. Variations in annual Coulomb stresses during modeled GERD operations are attributed to the seasonal load per unit area, and partially to the initial seasonal water level. The spatial patterns and amplitudes of these stress tensors are closely linked to both the size and timing of GERD inflow/outflow rates, and an improved understanding of the magnitude and extent of these stresses provides useful information to water managers to better understand potential reservoir triggered seismic events from several different operational and impoundment strategies.
Validating local drivers influencing land use cover change in Southwestern Ghana: a mixed-method approach
Sarfo I, Shuoben B, Otchwemah HB, Darko G, Kedjanyi EAG, Oduro C, Folorunso EA, Alriah MAA, Amankwah SOY and Ndafira GC
Addressing undesirable changes associated with the driving forces of land use cover change are critical to sustainable land management, and the future modeling of land use systems in developing countries. The study accentuates local drivers of land use cover change in Southwestern Ghana using a mixed-method approach. The approach aided in identifying key land-use drivers, using different research strategies for comparisons through confidence level analysis and Analytic Hierarchy Process. We used expert interviews, existing literature and geostatistical tools to ascertain the driving forces triggering such unprecedented changes. Landsat imagery 5 MSS, 4 and 5 TM, 7 ETM + and 8 OLI/TIRS were acquired from the United States Geological Survey's website. Land-use analysis revealed a decline in forests (- 82.41%) and areas covered by waterbodies (- 27.39%). A fundamental drift in built-up (+ 1288.36%) and farmlands/shrubs (+ 369.81%) areas were also observed. The contribution rate of change analysis revealed built-environment and increasing population contributed the most to surface temperature and land-use change. A steady increase in surface temperature can be attributed to the undesirable changes associated with land-use systems over the past 50 years. Socio-economic development in Southwestern Ghana is fuelling interest in studies related to land use cover change. Biophysical, cultural and technological factors are considered key drivers despite the "medium-to-very low confidence" in results generated. They could potentially impact climate-sensitive sectors that significantly modify land-use systems from the pessimists' and optimists' perspectives. Standpoints established through this study will enrich basic datasets for further studies at the continental level.
Changes in the constituents of the "Bosque de Agua" of the Sierra Cruces-Ajusco-Chichinautzín, Mexico, an area with payment for environmental services
López-García J and Navarro-Cerrillo RM
The "Bosque de Agua", to the west and south of Mexico City, which is the fifth largest city in the world, has historically suffered disturbances in forest cover, with a consequent reduction in the environmental services provided. Changes in the state of the forests between 1994 and 2017 are here analyzed in terms of the annual net change in area of the different cover densities and the different change processes. In general, the net change was favorable in all cases: forest improvement vs. forest degradation, reforestation vs. deforestation, and afforestation vs. land use change. There were changes in 16.03% of the : recovery in 11.09% and disturbance in 4.94%. This marked recovery is the result of the protected status of two-thirds of the forest, the payment for hydrological environmental services in 29.33% of the forest, as of 2003, and the continuous programs of reforestation, fire control and surveillance by the local communities, circumstances that have allowed the recovery to exceed the disturbance in most of the . One-third of the forest disturbance is concentrated in six of the 35 municipalities in the southern region, caused by clandestine logging by organized gangs, due to the state of ungovernability that reigns in these municipalities.
Surface water quality in the upstream of the highly contaminated Santiago River (Mexico) during the COVID-19 lockdown
Kutralam-Muniasamy G, Pérez-Guevara F, Roy PD, Elizalde-Martínez I and Chari SV
The Santiago River (Jalisco) is a major waterway in western Mexico and has received considerable attention due to its severe pollution. Understanding the impact of reduced human activity on water quality in the Santiago River during the COVID-19 lockdown (April-May 2020) is critical for river management and restoration. However, there has been no published study in this context, presenting a significant knowledge gap. Hence, this study focuses on determining if the nationwide COVID-19 lockdown influenced or improved surface water quality in a 262-km stretch of the Santiago River upstream. Data for 15 water quality parameters collected during the lockdown were compared to levels obtained in 2019 (pre-lockdown), 2021 (unlock), and the previous eleven years (2009-2019). The values of turbidity, BOD, COD, TSS, f. coli, t. coli, nitrate, sulfate, and Pb decreased by 4-36%, while pH, EC, total nitrogen, and As increased by 0.3-21% during the lockdown compared to the pre-lockdown period, indicating a reduction in organic load in the river due to the temporary closure of industrial and commercial activities. An eleven-year comparison estimated a 0-38% decline in pH, TSS, COD, total nitrogen, sulfates, nitrates, and Pb. The unlock-period comparison showed a significant rise of 3-37% in all parameters except As, highlighting the potential repercussions of restoring activity along the Santiago River. Estimated water quality indices demonstrated short-term improvements in river water quality during the lockdown when compared to other time periods investigated. According to factor analysis, the main pollution sources influencing river water quality were untreated household sewage, industrial wastewater, and agricultural effluents. Overall, our analysis showed that the COVID-19-imposed lockdown improved the water quality of the Santiago River, laying the groundwork for local officials to identify pollution sources and better support environmental policies and water quality improvement plans.
Assessing groundwater status and human perception in drought-prone areas: a case of Bankura-I and Bankura-II blocks, West Bengal (India)
Das M, Parveen T, Ghosh D and Alam J
Ground water is a precious natural resource in every aspect of human life from natural to artificial environment. Ground water is an indicator of regional development by improving the economic domain through intensive agricultural practices, and aesthetic value through sufficient ground water supply as drinking water, fertile soil, and healthy vegetation. However, ground water availability and associated human perceptions were the main themes of the present study. In this study, both primary and secondary data were incorporated to understand the human adaptation behaviour in drought-prone areas of the fringe of Chhotanagpur plateau region (Bankura-I and II blocks) to ground water storage. GWPZ mapping is a very important exposure to knowing the ground reality. So, the MCDM-AHP method has been developed based on the eight dominant conditioning factors viz. geomorphology, lithology, lineament density, soil, drainage density, LULC, average slope, and slope aspect using GIS analytics with field expertise. The output result was validated with comparing 105 inventory stations where 0.850 AUC value was good for accepting the GWPZ model. As a result, a major portion of the study area is dominated by poor to moderate possibilities of ground water level (ground water level drops 1-2 m during the pre-monsoon) due to Proterozoic granite gneiss formation over the study area. With comparing demographic status, it was not favourable for a healthy lifestyle. Agriculture dominated rural environment of Bankura-I and II blocks is far away from the modern digital environment that is why ground water has played a very crucial role in the field of development. Moreover, to build up a good level of ground water recharge zone through rainfall harvesting, and sustainable land use planning will be the best management practices. So, availability of ground water should be a positive sign of development in the field of the economic sector and sustainable human society.
Experimental research on deformation failure process of roadway tunnel in fractured rock mass induced by mining excavation
Li G, Ma F, Guo J and Zhao H
Deformation failure of roadways in fractured rock can lead to large-volume collapse and other engineering accidents. Failure mechanisms in fractured rock are complex and poorly understood, so to explore this issue, we simulated fractured rock masses using physical model tests in combination with numerical computations. A set of experimental techniques for roadway excavation under jointed surrounding rock included a mixed pouring-bricking method and a roadway excavation device, which can reproduce the structural characteristics of the prototype and replicate the excavation conditions of the roadway. Stress distribution characteristics of the roadway, from loading to excavation, were obtained based on strain monitoring and image acquisition, and the process of roadway deformation and failure was described in detail. A series of numerical simulations were conducted to investigate the deformation failure mechanisms of roadways under different excavation conditions. Results indicate that the deformation failure modes of roadways including collapse, rock burst, and floor heaving that were similar regardless of depth. Deformation failure modes of the roadway were determined by rock mass structure, and the deformation intensity was determined by geo-stress. Model testing and numerical simulation were consistent; hence, findings provide a theoretical basis and technical guidance for roadway engineering in fractured rock masses.
GIS approach for mapping novel coronavirus in northern state of India, Jammu and Kashmir
Meer MS and Mishra AK
Novel coronavirus "COVID-19" has affected worldwide. At initial stage, the way out to curb the deadly virus was lockdown, isolating the symptomatic people, quarantining travellers and educating the people about the coronavirus infection so that precautionary measures are followed by people. The present research focuses on the application of Geographic Information System on mapping the coronavirus cases in Jammu and Kashmir. The research attributes the role of dense population and urbanization responsible for increasing the coronavirus cases in the study area. The districts like Srinagar and Jammu with high population and urbanization (census 2011) attribute high number of corona cases in year 2020. This high population experiences the highest number of corona cases (Jammu 23,339, Srinagar 24,996), deaths (Jammu 350, Srinagar 444) and COVID-19 recoveries (Jammu 22,141, Srinagar 23,957). The highly urbanized and populated area are much exposed towards infection. The high number of corona case experiences heart-related issues. The number of heart-related deaths are increased to 29.6% during winter in study area by extreme weather conditions limiting regular exercising and outdoor activities. But, due to COVID-19 the amount of heart-related deaths has significantly increased, which is crucial for the study area. This study will serve as replica study for managing COVID-19 in Jammu and Kashmir and help the medical fraternity by giving the priority for vaccinating the people and managing the facility related to COVID-19. The GIS was used to mitigate the infection of COVID-19 on life.
Total organic carbon concentrations in clastic cave sediments from Butler Cave, Virginia, USA: implications for contaminant fate and transport
Riddell JL, Downey AR, Vesper DJ and Padilla IY
Clastic cave deposits are representative of sediments throughout the karst aquifer and thus are an abundant and accessible resource through which to study the chemistry of karst aquifer. Clastic cave sediments are attributed to depositional facies based on cave location, sorting, and particle size. These facies settings may influence different chemical parameters of the sediments, like concentrations of total organic carbon (TOC). The TOC concentrations in clastic cave sediments have not been well constrained nor has the role of clastic sediments in contaminant fate and transport through karst systems been well described. In this study, particle size, TOC, and total nitrogen were measured in sediments representing different facies in Butler Cave, Virginia, USA. TOC concentrations ranged from 0.08 - 0.87 weight percent and C:N molar ratio ranged from 3 - 15, indicating a possible terrestrial source of organic carbon in these sediments. The diamicton facies was sandier and but had similar TOC concentrations compared to the channel facies. TOC concentrations measured in Butler Cave were within the same range as those observed in above water, eogenetic clastic cave sediments from two caves in Puerto Rico. Estimated retardation factors calculated based on the TOC concentrations in the Butler Cave sediments indicate the range of TOC in this cave could be responsible for 39 - 987% increase in retardation of selected contaminants. This study highlights the importance of measuring the ranges of TOC in clastic cave sediments across different facies and their role in contaminant fate and transport.