Natural Groundwater Research Articles

Formation of Biogenic Manganese Oxide Nodules on Hyphae of a New Fungal Isolate of Periconia That Immobilizes Aqueous Copper.

Mn(II)-oxidizing microorganisms are considered to play significant roles in the natural geochemical cycles of Mn and other heavy metals because the insoluble biogenic Mn oxides (BMOs) that are produced by these microorganisms adsorb other dissolved heavy metals and immobilize them as precipitates. In the present study, a new Mn(II)-oxidizing fungal strain belonging to the ascomycete genus Periconia, a well-studied plant-associating fungal genus with Mn(II)-oxidizing activity that has not yet been exami-ned in detail, was isolated from natural groundwater outflow sediment. This isolate, named strain TS-2, was confirmed to oxidize dissolved Mn(II) and produce insoluble BMOs that formed characteristic, separately-located nodules on their hyphae while leaving major areas of the hyphae free from encrustation. These BMO nodules also adsorbed and immobilized dissolved Cu(II), a model analyte of heavy metals, as evidenced by elemental mapping ana-lyses of fungal hyphae-BMO assemblages using a scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX). Analyses of functional genes within the whole genome of strain TS-2 further revealed the presence of multiple genes predicted to encode laccases/multicopper oxidases that were potentially responsible for Mn(II) oxidation by this strain. The formation of BMO nodules may have functioned to prevent the complete encrustation of fungal hyphae, thereby enabling the control of heavy metal concentrations in their local microenvironments while maintaining hyphal functionality. The present results will expand our knowledge of the physiological and morphological traits of Mn(II)-oxidizing Periconia, which may affect the natural cycle of heavy metals through their immobilization.

Eco-friendly and stable triclosan removal from groundwater using peroxyacetic acid activated with biochar produced from saccharification residues

Biochar is a cost-effective activator in advanced oxidation processes, its progressive release of soluble substances during application can potentially reduce the stability of its activation efficiency and induce secondary environmental pollution. Addressing these drawbacks of biochar, this study focused on enhancing its stability and the efficacy of peracetic acid (PAA) in removing triclosan from groundwater, employing a saccharification residue-based biochar (BC-SR). The research findings indicated that the efficacy of triclosan removal by BC-SR/PAA surpassed that of ordinary biochar (BC-O) by 1.33 times. Furthermore, utilizing the response surface methodology design, the synergistic efficiency of BC-SR/PAA was enhanced, achieving a removal rate of up to 90%. The high removal efficiency of BC-SR could be attributed to its microporous structure, surface area, loss of stability, and thermal stability, which were all significantly better than BC-O. Even after 10 cycles of reuse, the removal efficiency of BC-SR still maintained 77% of its initial efficiency. Notably, the activation mechanism of BC-SR/PAA was different from typical carbonaceous materials, as the degradation system's main active substances were ·O2− and 1O2, and BC-SR's active sites may be its surface's persistent free radicals. Moreover, column tests using natural groundwater and soil emulated BC-SR's role as a permeable reactive barrier. Results underscored the BC-SR/PAA system's formidable removal and anti-interference abilities. Analysis showed triclosan degradation products have lower toxicity, highlighting their practical value. This research addresses the challenge of inadequate removal efficiency and secondary pollution in in-situ groundwater remediation, particularly associated with complex substrates. This approach, unlike biochar ‘burdening’, offers a novel concept for ‘de-burdening’ biochar activation.

Study on the nutritional composition of the sea vegetable Ulva compressa in a brine-based cultivation system

Driven by the global need of alternative food sources, there is a rising interest in edible macroalgae (seaweeds). In order to provide fresh and healthy seafood even in inland areas, land-based, environmentally controlled seaweed farming is on the rise. Facing several issues, especially the need of suitable cultivation media increases with growing distance from the coast. In order to provide regional solutions and make the cultivation approaches more sustainable, the present study investigates the potential use of natural saline ground water (brine) for the production of the macroalga Ulva compressa in inland cultivation systems. Over a period of 88 days, macroalgal thalli were cultivated in aerated experimental units (120 L) filled with brine-based media or commercial artificial sea water. Physicochemical properties of the cultivation media and the nutritional profile of macroalgal thalli were analyzed after 52 and 88 days of cultivation. The results underline not only the feasibility to use brine in the farming of sea vegetables (e.g. overcoming the lack of seawater and reduction of freshwater use), but also clearly indicate a nutrional value for the U. compressa cultivation, resulting in algal thalli, rich in polyunsaturated fatty acids and carotenoids (e.g. lutein, β carotene). The present findings might serve as a step stone for the further development of brine-based inner land aquaculture systems.

Hydrogeochemical Evaluation of Aquifer Storage and Recovery in Edwards Aquifer, New Braunfels, Texas.

This study examines the potential for aquifer storage and recovery (ASR) in the brackish portion of the Edwards aquifer in New Braunfels, Texas. Successful ASR relies on understanding hydraulic properties, aquifer heterogeneity, water geochemistry, and geochemical processes during operations. The research aims to investigate the chemistries of native groundwater and injectant during ASR operation, estimate the hydraulic properties of the aquifer layers, and assess the recovery rate for the recovered groundwater meeting the total dissolved solids (TDS) threshold. The study found that native groundwater is of Na-Cl facies due to halite dissolution and a possible basinal brine migration associated with the zone of greatest fault displacement. High sulfate ions in background native groundwater result from sulfate-bearing minerals' dissolution in the Kainer and Person Formations. The injectant water is of Ca-Mg-HCO3 facies due to the carbonate-rich composition of the aquifer host matrix and interaction with the Guadalupe River riverbed. During ASR operations, mixing controlled the shift in hydrochemical facies from Na-Cl to Ca-Mg-HCO3.The study also suggests a possible connection between Kainer and Person Formations and preferential pathways in the targeted storage zone aquifer. The estimated conductivity values also indicate dominant horizontal flow via possible fracture pathways in both the Person and Kainer Formation storage zones. Recovery of groundwater meeting the TDS of 1000 mg/L requires a recovery rate of 0.03 m3/s for 60 days after 40-day storage. This research emphasizes that understanding the hydrogeological conditions and geochemical processes is critical to ASR feasibility in brackish carbonate multi-aquifer fractured systems.

In-situ groundwater treatment for arsenic removal: laboratory pilot scale study with 3-D tank packed porous media as subsurface

ABSTRACT The ex-situ treatment of arsenic is widely adopted; however, there are emerging concerns related to system maintenance, material replacement, and waste generation. There is a scope to explore in-situ arsenite [As (III)] remediation in the aquifers. The main objective of this study is to evaluate the performance of in-situ synthesised FeS in immobilising As (III) in the natural groundwater when transported through a three-dimensional (3-D) porous media system. In this study, a 3-D tank of 0.50 m × 0.30 m × 0.30 m (L × W × H) was packed with natural sand to represent the subsurface porous media system. The homogeneous packing and uniform flow were ensured before synthesising FeS in-situ, where a total of 1.5 pore volumes (PVs) of 20 mM sodium sulfide (Na2S) and 20 mM ferrous sulfate (FeSO4) reagent solutions were injected alternatively into the pre-saturated porous media. Finally, 300 ± 15 μg/L of As (III) spiked natural groundwater was passed through the porous media, and the samples were collected through several sampling ports for analysing for total As and Fe. The result suggests that the concentration of As (III) reaches below 11 μg/L within 644 min (4 PVs) of injection of reagents. Furthermore, almost 88.4% of As (III) get immobilised after passing 31 PVs of contaminated water. In brief, almost 406 L of As contaminated groundwater can be treated by injecting 21 L of reagents with a reagent-to-treated water ratio of 1:20.

Groundwater nitrate pollution risk assessment based on the potential impact of land use, nitrogen balance, and vulnerability

The predicting groundwater nitrate pollution risk, especially in terms of changes in fertilizing, has not been fully investigated so far. In particular, there is no comprehensive method to assess this risk in areas of different land use type, and not only in agricultural areas. The aim of this study was to develop a novel multicriteria methodology for groundwater nitrate pollution risk assessment, which meets these issues. A further aim was to determine how much this risk would change if the amount of organic and synthetic fertilization was reduced. An assumption was that groundwater pollution risk is a combination of the potential adverse impacts of land use, fertilization, and intrinsic groundwater vulnerability to pollution. The impact of fertilization was holistically evaluated by balancing nitrogen from spatially differentiated the size of the breeding, species of livestock, manure and synthetic fertilizers input, and spatially differentiated topsoil, with nitrogen uptake by different crops. The nitrate concentration in the leachate was used as a measure of the impact of fertilization. This concentration was compared to the natural baseline nitrate concentration in groundwater. Three fertilization scenarios for groundwater pollution risk assessment in two study areas were discussed. Under typical agricultural, climatic, soil, and geological conditions in Europe for the current total fertilization level of 95-120 kg N ha−1 groundwater nitrate pollution risk is low and moderate, but for fertilization of 150-180 kg N ha−1, a reduction in the total fertilization (synthetic and manure) by 40 to 50% may be required to achieve low risk of degradation of natural groundwater quality. Predictive simulations of groundwater nitrate pollution risk confirmed that reducing synthetic and organic fertilization has an effect, especially in areas with intensive fertilization. This method may allow for a holistic and scenario-based assessment of groundwater pollution risk and may help decision-makers introduce solutions to manage this risk under conditions of climate change, preservation of groundwater quality, and food security.

Geophysical signatures of soil AFFF contamination from spectral induced polarization and low field nuclear magnetic resonance methods

Few field methods are available for characterizing source zones impacted with aqueous film forming foam (AFFF). Non-invasive geophysical characterization of AFFF source zone contamination in situ could assist with the delineation and characterization of these sites, allowing for more informed sampling regimes aimed at quantifying subsurface poly- and perfluoroalkyl substances (PFAS) contamination. We present initial results from the investigation of the sensitivity of two existing surface and borehole-deployable geophysical technologies, spectral induced polarization (SIP), and low field nuclear magnetic resonance (NMR), to soils impacted with AFFF. To investigate the sensitivity of these methods to AFFF-impacted soil, bench-scale column experiments were conducted on samples consisting of natural and synthetic soils and groundwater. While our findings do not show strong evidence of NMR sensitivity to soil PFAS contamination, we do find evidence that SIP has sufficient sensitivity to detect sorption of AFFF constituents (including PFAS) to soils. This finding is based on evidence that AFFF constituents associated with the pore surface produce a measurable polarization response in both freshly impacted synthetic soils and in soils historically impacted with AFFF. Our findings encourage further exploration of the SIP method as a technology for characterizing contaminant concentrations across AFFF source zones.

Strom Water Drainage Design – A Case Study

Strom water drainage drains excess water from streets, sidewalks, roofs, buildings and other areas. A system used to drain strom water at various places has different names like sewers and drainage wells. Strom water can be any rainfall, such as rain, snow and sleet that falls on the surface of the earth. In areas with natural groundwater, about 10% of the precipitation becomes runoff and about 50% infiltrates into the soil to form or replenish groundwater and flows into streams. In view of the existing status of drainage systems in urban areas that cause frequent flooding leading to loss of property and life, it necessitates looking into the problem more closely and coming out with planning, designing, implementation and operation & maintenance guidelines to overcome the problems in urban areas. In this paper study of the drainage system of Bharti Vidyapeeth complex is shown which has been done throughout the project. Various phrases has been studied during the study of this particular project. It has been found that drainage system is not a factor that depends on a single particular section but equally on various interrelated factors .In this research paper, one can have idea about the several methods which has been used throughout the project.

Managing Earthquake Debris: Environmental Issues, Health Impacts, and Risk Reduction Measures

Earthquakes have the potential to cause severe and widespread structural damage to buildings and infrastructure in the affected area. Earthquake debris mainly results from building collapses during intense ground motion and the emergency demolition of damaged and unstable buildings following a devastating earthquake. Debris management constitutes a major challenge that must be met by all those participating in disaster management as it poses threats to both the natural environment and public health in an earthquake-affected area. This narrative review examines the hazards that arise throughout the early phases of debris removal, when personnel operate in disaster-affected areas, to the last steps of sorting and disposal. Furthermore, emphasis is also given to the environmental impact caused by unregulated debris disposal on natural habitats that are highly sensitive and susceptible to hazardous substances and materials found in the debris. In the same framework, measures are proposed for alleviating the negative impacts of debris management on the well-being of all individuals involved, including workers, volunteers, and the local community, as well as the surrounding natural environment, encompassing soil, surface and groundwater, as well as air quality.

Erosion mitigation with biocementation: a review on applications, challenges, & future perspectives

AbstractSoil erosion is a complex natural process that occurs by either individual or combined actions of wind, hydraulic currents, waves, and rain. This study comprehensively reviews biocementation-based soil stabilisation techniques for developing erosion-resilient landforms through an ecologically conscious strategy. The different pathways for biocementation occurring in nature are discussed with a focused view on the microbially induced carbonate precipitation (MICP) technique. MICP relies on biogenic calcium carbonate (CaCO3) precipitation via the urea hydrolysis route to bind the soil grains. The kinetics and factors affecting MICP are succinctly discussed to highlight the practical challenges associated with biocementation. This study emphasises the influence of MICP on erosion resistance (aeolian and hydraulic) and geotechnical properties of soils. The critical assessment of the previous studies revealed that aeolian and hydraulic erosion can be effectively controlled with a small to moderate quantity of biogenic CaCO3 (2% to 10% of soil weight). MICP marginally influences the hydraulic conductivity of soils with a substantial improvement in compressive strength, making it desirous over traditional soil cementation agents for erosion control due to the limited intervention to natural groundwater flow. However, the scientific design and findings of the previous laboratory-scale and pilot-scale research are still inconsistent for standardising biocementation techniques to transition towards upscaling. This study presents critical insights to the researchers of the environmental, geotechnical and geoenvironmental engineering domains to design their upcoming studies to tackle the challenges required for upscaling biocementation technology.

Gypsiferous groundwater and its desalination brine concentrate: Biomass, water use, and salt “mining” of three Southwestern USA native halophytes

In drought affected regions, alternative water sources and salt tolerant crops have become increasingly important. Although there is extensive documentation describing the response of halophytes to NaCl laboratory solutions, limited data exist on their responses to natural brackish groundwater (BGW) and desalination brine concentrate that could be dominated by ions other than Na and Cl. This study investigated the biomass, evapotranspiration (ET), water productivity (WP), and ion uptake responses of three southwestern USA native halophyte species, Atriplex canescens (Pursh) Nutt. (fourwing saltbush), A. lentiformis (Torr.) S. Watson (big saltbush), and Lepidium alyssoides A. Gray var. alyssoides (mesa pepperwort). Six-week-old seedlings were irrigated with a nonsaline control treatment solution [electrical conductivity (EC) of 0.6 dS m-1], CaSO4-dominant BGW (EC ≈ 4 dS m-1), CaSO4-dominant reverse osmosis (RO) concentrate (EC ≈ 8 dS m-1), and counterpart NaCl-dominant solutions (EC ≈ 4 or 8 dS m-1). After 6 wk, BGW and low NaCl solutions increased shoot biomass of . A. lentiformis by ≈ 20% but did not stimulate top growth of A. canescens or L. alyssoides. Increasing salinity had no effect on WP of L. alyssoides, but it increased WP of the Atriplex spp. The combined shoot Na and Cl concentrations reached 7% of dry wt. in L. alyssoides and 9–10% in the Atriplex spp. with no characteristic signs of leaf burn. Conversely, roots were the main sinks for Ca and S, combining for 6–7% of dry wt. and showing the potential to put the main brine solutes to beneficial use. Markedly similar patterns in growth and water use with the NaCl-only solutions and the CaSO4-dominant solutions suggests a primary role of total salinity in these salinity responses, which in turn supports the use of diverse BGW typesnot just NaCl for halophyte production.

Synthesis and exploration of physical properties of nanobiochar synthesized from rice straw for its applications in arsenic remediation from contaminated water environments

Arsenic (As) is a widespread carcinogenic element that emerges due to geogenic and anthropogenic processes and poses detrimental effects on public health. Biochar is a carbonaceous, renewable, and sustainable material synthesized under low or absent oxygen. Thus, the present study explores the application of biochar obtained via pyrolysis at 500 °C for 2 hrs, followed by ball milling for 3 hrs at 500 rpm to obtain nanobiochar materials for As removal from contaminated environments. Characterization of biochar has been performed for physico-chemical analysis. Different functional groups, including hydroxyl, carboxyl, and alkene, are observable using Fourier Transform Infrared Spectroscopy, contributing to As removal from water. Scanning Electron Microscope analysis shows the porous nature of nanobiochar, which also contributes to remediation. Transmission electron microscope analysis shows an average particle size of nearly 28.12 nm. The As(V) removal efficiency was obtained with an adsorption capacity of 55.1 µg/g at pH 8 to mimic natural water conditions for 6 hrs of biochar-arsenic interactions. The possible adsorption mechanisms of As species on biochar surfaces are electrostatic attractive forces, surface chemical bonding, ion exchange, and precipitation. Future research must concentrate on applications of low-cost, renewable, and carbon material, i.e., biochar for decontaminating natural groundwater samples containing various emerging contaminants for safe and clean drinking water.

Stable microbial community in compacted bentonite after 5 years of exposure to natural granitic groundwater.

The Materials Corrosion Test (MaCoTe) at the Underground Research Laboratory in Grimsel, Switzerland, assesses the microbiology and corrosion behavior of engineered barrier components of a deep geological repository (DGR) for long-term disposal of high-level nuclear waste. Diversity and temporal changes of bentonite-associated microbial community profiles were assessed under DGR-like conditions for compacted Wyoming MX-80 bentonite (1.25 g/cm3 and 1.50 g/cm3 targeted dry densities) exposed to natural groundwater. Using culture-dependent and molecular techniques, samples taken from the outside layer of 5-year borehole modules revealed up to 66% and 23% of 16S rRNA gene sequences affiliated with Desulfosporosinus and Desulfovibrio, respectively. Putatively involved in sulfate reduction, these taxa were almost undetectable within the bentonite core. Instead, microbial profiles of the inner bentonite core were similar to uncompacted bentonite used to pack modules years earlier, and were consistent with a previously published 1-year time point, revealing no detectable microbial growth. Abundances of culturable aerobic and anaerobic heterotrophic bacteria in the uncompacted bentonite were relatively low, with less than 1,000 and 100 colony-forming units (CFUs) per gram dry weight, respectively. Nearly 5 years after emplacement, culturable heterotrophic bacterial CFUs and sulfate-reducing bacteria did not change significantly inside the bentonite core. Phospholipid fatty acid data indicated similar lipid abundance, and corresponding cell abundance estimates, for inner 5-year MaCoTe bentonite samples compared to those previously obtained for 1-year incubations. Collectively, our results provide complementary evidence for microbial stability inside highly compacted bentonite exposed to conditions that mimic engineered barrier components of a deep geological repository. IMPORTANCE The long-term safety of a deep geological repository for used nuclear fuel is dependent on the performance of the engineered and natural barriers. Microbial activity can produce chemical species that can influence the corrosion of the disposal containers for used nuclear fuel. Although previous studies have evaluated the microbiology of compacted bentonite clay within subsurface environments, these have been limited to relatively short incubations (i.e., 1 year). The current study provides a unique 5-year perspective that reinforces previous findings of growth inhibition for bentonite clay exposed to in situ subsurface conditions.

A comprehensive and systematic study of geothermal energy-based desalination systems for sustainable development

ContextGeothermal energy is one of the most promising renewable energy sources as it is a power source that produces electricity with minimal environmental impact. It has been proven that among renewable energy sources, it is the most reliable, safe, and clean, and therefore it is used for power production, heating, and cooling. The importance of geothermal desalination is beneficial in areas lacking natural groundwater or surface water supplies. Over time, water reuse desalination can solve water scarcity and, in some countries, provides over 90 % of the total water supply. The novelty of the workThis research presents an in-depth analysis of the desalination of seawater utilizing geothermal energy as the primary resource. It will also evaluate the risks and market possibilities of the system and the constraints on further development. MethodologyThe method of geothermal desalination has also been briefly covered, along with the most common cycles of thermal desalination. These cycles include multi-effect distillation, multistage flash distillation, and vapor compression. Main results and related interpretationsGeothermal desalination technologies address worldwide water scarcity sustainably and effectively. Geothermal energy can make desalination more sustainable and environmentally friendly. Compared to conventional fossil fuel-based systems, desalination using geothermal energy can result in lower overall energy usage and CO2 emissions.

Spectral characterization of dissolved organic matter in groundwater to assess mixing with oil-field water near selected oil fields, southern California

Samples of oil-field water (oil wells, injectate, disposal ponds) and groundwater near selected oil and gas fields in southern California were analyzed for dissolved organic carbon (DOC) concentration and by optical spectroscopic techniques (i.e., absorbance and fluorescence) to assess whether these measurements can be used to distinguish between oil-field water (Oil Field), native groundwater (WGnat), and native groundwater mixed with oil-field water from surface (WGsurf) or subsurface sources (WGsub), and if so whether commonly reported optical measurements can be used as a screening tool to identify such water. Concentrations of DOC were significantly (p < 0.0001) higher (67 to 2934 mg C L−1) in oil-field water compared to native groundwater samples (<5.0 mg C L−1). Individual optical properties varied by water category and frequently overlapped. However, multivariate statistical analysis showed that when evaluated in combination, 10 optical properties were determined by discriminant analysis to be significant (p < 0.05) in distinguishing among water categories. Principal component analysis of those 10 optical properties showed that these properties can be used to successfully distinguish Oil Field samples from WGnat, WGsurf, and WGsub even when mixing fractions are low (approximately 10 %).

Adsorptive behavior of Fe/Zn-modified nanobiochar for arsenic removal from naturally contaminated groundwater

Global groundwater is frequently discovered to have high arsenic (As) concentrations, critically endangered and potentially toxic to aquatic organisms and humans. This work investigates As(V) adsorption using raw nanobiochar (RnBC) and activated magnetic nanobiochar (AMnBC), which are synthesized via pre-treating rice straw biomass with ZnCl2 and FeCl3 and pyrolyzing at 500 °C, followed by ball milling. The highest adsorption capacity for AMnBC and RnBC was 130 μg/g and 38.67 μg/g, respectively, at alkaline water chemistry to mimic natural groundwater conditions. Different functional groups contributed by modifications are evident with As(V) adsorption using RnBC and AMnBC. Multilayer chemisorption may explain the adsorption of As(V) on biochar surfaces, as Freundulich isotherm and pseudo-second-order kinetic model are suggested. The synthesis cost for AMnBC and RnBC was $0.0147/g and $0.0099/g, respectively, which helped to determine the most effective and efficient method for As(V) adsorption. In this study, natural As-contaminated groundwater collected from Patna, Bihar (India), was treated for As(V) removal using AMnBC in natural environments. Thus, this study recommends that cost-effective modified biochar can effectively be used for As(V) elimination from naturally contaminated groundwater as well as surface water.

Soil Conservation Service-Curve Number method-based historical analysis of long-term (1936-2016) temporal evolution of city-scale potential natural groundwater recharge from precipitation: case study Algiers (Algeria).

Managing groundwater resources in urban areas requires an adequate understanding and assessment of urban hydrogeological systems (structure, components, connections, and imposed conditions) as a part of a larger, dynamically evolving environment. Urbanization and climate change are amongst the widely recognized signs of such a continuous evolution. Within this context, the present study gives a quantitative assessment of the impact of these two factors threatening water resources in urban environments. The Soil Conservation Service-Curve Number (SCS-CN) method is used to conduct a long-term quantitative analysis of the temporal evolution of the potential natural groundwater recharge from precipitation at the scale of Algiers city for an 80-year-long period (1936-2016). The length of the study period allowed us to account for and analyze important changes in urban settings and climatic conditions within the study zone. Overall, two trend shifts over three distinct periods were found to characterize the temporal evolution of precipitation, several climate change indicators defined for the study, and the potential natural aquifer recharge. A strong, approximately 1:4, linear correlation between the estimated city-scale potential natural aquifer recharge and precipitation was observed for the studied period (R2 = 0.748). Moreover, even though the urban area has known a rapid (2nd order polynomial) increase from 1936 to 2016, climate change (accounted for via the changes in precipitation regime) impacted the city-scale potential natural groundwater recharge with higher magnitudes than urbanization. Finally, the computed climate change indicators show that starting in the mid-1980s, Algiers has started receiving less precipitations, with fewer heavy rain events and longer dry condition periods.

Natural groundwater outflows in the Biebrza Valley: Temporal stability, geochemical composition and role in ecohydrological processes of valley wetlands

Natural groundwater outflows are very sensitive to changes in the environment. In the era of changing climate and progressive anthropogenic activity, they often disappear, retreat, and water quality deteriorates. Inefficient sources in lowland areas are the most vulnerable to these processes. In 2021, we conducted an inventory of natural groundwater outflows in the Biebrza Valley. Most of the existing outflows are non-concentrated outflows (exudations, linear leakages, fens). The outflow of several outflows exceeded 5 dm3·s−1. Their distribution within the Biebrza Basin is uneven. We identified the largest concentration of linear seepages on the right bank of the lower Biebrza basin near the village of Ruś. The most common types in the BNP are di- and tri-ionic waters, characteristic of lowland areas of Poland. The increase in nitrogen and phosphorus compounds in the spring water indicates the impact of the developing agricultural activity (cattle breeding). The increase in DOC concentration may reflect changing hydro-meteorological conditions (droughts and torrential rains). The values of most parameters in spring water were lower than in shallow groundwater. This gives a better picture of the quality of shallow groundwater. The physical and chemical characteristics of natural groundwater outflows in the BNP fall within the hydro-chemical background of the waters of the first aquifer in this area.

Influence assessment of urban expansion on groundwater level fluctuations in Gandhinagar, Gujarat, India.

Being the state capital of Gujarat, Gandhinagar is snowballing urban population, resulting in overexploitation of groundwater resources and consequent decline in local groundwater level. The key objective of the current research is to understand the impact of urban expansion on the groundwater level of Gandhinagar district for the last 3 decades. Long-term land use/land cover (LULC) alterations using Landsat images (1991-2021) reveal a 234% increase in overall built-up area and it is more prominent in western and southern parts than the eastern part of study area till 2021 due to urban sprawl of adjacent Ahmedabad City. Spatial distribution of groundwater levels exhibits the same pattern of groundwater level drop as that of the urban expansion and the drop of maximum depth of the groundwater level has also observed during study tenure. Rapid population growth indicates inevitable urban densification which may lead to increase in groundwater abstraction and consequent groundwater level depletion of Gandhinagar City in near future. The scenario may be worsened due to the reduction in groundwater recharge area owing to enhancement of impervious surfaces. A negative correlation is established between groundwater level and respective built-up areas from 1991 to 2011. After 2001, groundwater levels in some areas showed a rising trend and the number of those locations have increased from 2001 to 2021, indicating a sufficient supply of surface water, meeting the escalating water demand and subsequent reduction in groundwater abstraction. High fluoride content was found in many groundwater samples collected from Gandhinagar's shallow unconfined aquifer. In lieu of almost unperturbed natural groundwater recharge, built-up expansion, rising population, and over-exploitation result in groundwater level depletion in both shallow and deeper aquifers. To replenish the already depleted groundwater level and for sustainable water supply, an integration of rainwater-surface water-groundwater management plan and sustainable urban management plan is highly required. The future sustainable urban-groundwater management plan of Gandhinagar City must emphasized on the expansion of green and permeable spaces for groundwater recharge, mandatory rainwater harvesting system in every building possible, suitable area demarcation for artificial recharge, and identification of areas which are less prone to groundwater level depletion for city expansion. The outcomes of the present study will help the decision-makers to prepare inclusive and resilient urban management plan to accomplish the 6th and 11th Sustainable Development Goals of United Nations by 2030.

Resource utilization of rice straw to prepare biochar as peroxymonosulfate activator for naphthalene removal: Performances, mechanisms, environmental impact and applicability in groundwater

Herein, biochar was prepared using rice straw, and it served as the peroxymonosulfate (PMS) activator to degrade naphthalene (NAP). The results showed that pyrolysis temperature has played an important role in regulating biochar structure and properties. The biochar prepared at 900°C (BC900) had the best activation capacity and could remove NAP in a wide range of initial pH (5-11). In the system of BC900/PMS, multi-reactive species were produced, in which 1O2 and electron transfer mainly contributed to NAP degradation. In addition, the interference of complex groundwater components on the NAP removal rate must get attention. Cl− had a significant promotional effect but risked the formation of chlorinated disinfection by-products. HCO3−, CO32−, and humic acid (HA) had an inhibitory effect; surfactants had compatibility problems with the BC900/PMS system, which could lead to unproductive consumption of PMS. Significantly, the BC900/PMS system showed satisfactory remediation performance in spiked natural groundwater and soil, and it could solve the problem of persistent groundwater contamination caused by NAP desorption from the soil. Besides, the degradation pathway of NAP was proposed, and the BC900/PMS system could degrade NAP into low or nontoxic products. These suggest that the BC900/PMS system has promising applications in in-situ groundwater remediation.