Trace element pollution tracking in the complex multi-aquifer groundwater system of Al-Hassa oasis (Saudi Arabia) using spatial, chemometric and index-based techniques.

In a global context, trace element pollution assessment in complex multi-aquifer groundwater systems is important, considering the growing concerns about water resource quality and sustainability worldwide. This research addresses multiple objectives by integrating spatial, chemometric, and indexical study approaches, for assessing trace element pollution in the multi-aquifer groundwater system of the Al-Hassa Oasis, Saudi Arabia. Groundwater sampling and analysis followed standard methods. For this purpose, the research employed internationally recognized protocols for groundwater sampling and analysis, including standardized techniques outlined by regulatory bodies such as the United States Environmental Protection Agency (USEPA) and the World Health Organization (WHO). Average values revealed that Cr (0.041) and Fe (2.312) concentrations surpassed the recommended limits for drinking water quality, posing serious threats to groundwater usability by humans. The trace elemental concentrations were ranked as: Li < Mn < Co < As < Mo < Zn < Al < Ba < Se < V < Ni < Cr < Cu < B < Fe < Sr. Various metal(loid) pollution indices, including degree of contamination, heavy metal evaluation index, heavy metal pollution index, and modified heavy metal index, indicated low levels of groundwater pollution. Similarly, low values of water pollution index and weighted arithmetic water quality index were observed for all groundwater points, signifying excellent groundwater quality for drinking and domestic purposes. Spatial distribution analysis showed diverse groundwater quality across the study area, with the eastern and western parts displaying a less desirable quality, while the northern has the best, making water users in the former more vulnerable to potential pollution effects. Thus, the zonation maps hinted the necessity for groundwater quality enhancement from the western to the northern parts. Chemometric analysis identified both human activities and geogenic factors as contributors to groundwater pollution, with human activities found to have more significant impacts. This research provides the scientific basis and insights for protecting the groundwater system and ensuring efficient water management.

Effective voltammetric tool for Nano-detection of triazine herbicide (1-Chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) by naphthalene derivative.

The development and operation of a nanosensor for detecting the poisonous 1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine (Atrazine) are described in this study for the first time. The carbon electrode (CE) surface was modified with cysteine-substituted naphthalene diimide to create this sensitive platform. The developed nanosensor (NDI-cys/GCE) was evaluated for its ability to sense Atrazine using differential pulse voltammetry and cyclic voltammetry. To achieve the best response from the target analyte, the effects of several parameters were examined to optimize the conditions. The cysteine-substituted naphthalene diimide significantly improved the signals of the Atrazine compared to bare GCE due to the synergistic activity of substituted naphthalene diimide and cysteine molecules. Under optimal conditions, atrazine detection limits at the (NDI-cys/GCE) were reported to be 94 nM with a linear range of 10-100 µM. The developed sensing platform also showed positive results when used to detect the atrazine herbicide in real tap water, wastewater, and milk samples. Furthermore, a reasonable recovery rate for real-time studies, repeatability, and stability revealed that the developed electrochemical platform could be used for sample analysis.

Insights into chitosan-based cellulose nanowhiskers reinforced nanocomposite material via deep eutectic solvent in green chemistry.

In the present work, the synthesis of cellulose nanowhiskers (CNW)/chitosan nanocomposite films via deep eutectic solvents (DES) changing the chemical structures were carried out. It was observed that a pure chitosan film has broadband at 3180-3400 cm-1, indicating amide and hydroxyl groups. Upon CNW incorporation, the peak gets sharper and stronger and shifts to a greater wavelength. Further, the addition of DES infuses more elements of amide into the nanocomposite films. Moreover, the mechanical properties incorporating CNW filler into a chitosan matrix show an enhancement in tensile strength (TS), Young's modulus (YM), and elongation at break. The TS and YM increase while the elongation decrease as the CNW concentration increases. The YM of biocomposite films is increased to 723 MPa at 25% CNW into chitosan films. Besides, the TS has enhanced to 11.48 MPa at 15% CNW concentration in the biocomposite films. The elongation at break has decreased to 11.7% at 25% CNW concentration. Hence, incorporating CNW into the chitosan matrix via DES can still improve the mechanical properties of the nanocomposite films. Therefore, the application of DES results in a lower YM and TS as the films are hygroscopic. In conclusion, DES can be considered the new green solvent media for synthesizing materials. It has the potential to replace ionic liquids due to its biodegradability and non-toxic properties while preserving the character of low-vapour pressure. Besides that, chitosan can be used as potential material for applications in process industries, such as the biomedical and pharmaceutical industries. Thus, DES can be used as a green solvent and aim to reduce the toxic effect of chemicals on the environment during chemical production.

Graphene oxide-based novel MOF nanohybrid for synergic removal of Pb (II) ions from aqueous solutions: Simulation and adsorption studies.

Heavy metals represent a considerable threat, and the current study deals with synthesizing a novel MOF nanocomposite by intercalating graphene oxide (GO) and linker UiO-66-NDC. It was shown that UiO-66-NDC/GO had enhanced the removal efficiency of Pb (II) ions at pH 6. The adsorption kinetics data followed the PSO (Type 2) representing chemisorption. Adsorption data were also fitted with three different isotherms, namely Temkin, Freundlich, & Langmuir, and the Temkin model exhibited the best correlation (R2 0.99), representing the chemisorption nature of the adsorption process. The maximum adsorption capacity (qmax) of Pb (II) ions using Langmuir was found to be 254.45 mg/g (298 K). The Pb (II) adsorption process was confirmed to be exothermic and spontaneous as the thermodynamic parameters H° and G° were determined to have negative values. MOF nanocomposite also represents significant reusability for up to four regeneration cycles using 0.01 M HCl; for the next four, it works quite efficiently after regeneration. Meanwhile, the simulation findings confirm the superior dynamic stability (∼08 times) of the MOF nanocomposite as compared to the GO system. The removal of Pb (II) from simulated wastewater samples using a super nano-adsorbent using a MOF nanocomposite is described here for the first time.

Comparison of constructed wetland performance coupled with aeration and tubesettler for pharmaceutical compound removal from hospital wastewater.

Pharmaceutical compounds being able to alter, retard, and enhance metabolism has gained attention in recent time as emerging pollutant. However, hospitals which are part of every urban landscape have yet to gain attention in terms of its hospital wastewater treatment to inhibit pharmaceutical compounds from reaching environment. Hence this study evaluated performance of constructed wetland in combination with tubesettler and aeration based on removal efficiency and ecological risk assessment (HQ). The removal efficiency of constructed wetland with plantation was higher by 31% (paracetamol), 102% (ibuprofen), 46%, (carbamazepine), 57% (lorazepam), 54% (erythromycin), 31% (ciprofloxacin) and 20% (simvastatin) against constructed wetland without plantation. Constructed wetland with aeration efficiency increased for paracetamol, ibuprofen, carbamazepine, lorazepam, erythromycin, ciprofloxacin, and simvastatin removal efficiency were higher by 58%, 130%, 52%, 79%, 107%, 57%, and 29% respectively. In constructed wetland with plantation, removal efficiency was higher by 20% (paracetamol), 13% (ibuprofen), 4% (carbamazepine), 14% (lorazepam), 34% (erythromycin), 19% (ciprofloxacin) and 7% (simvastatin). High ecological risk was observed for algae, invertebrate and fish with hazard quotient values in range of 2.5-484, 10-631 and 1-78 respectively. This study concludes that if space is the limitation at hospitals aeration with constructed wetland can be adopted. If space is available, constructed wetland with tubesettler is suitable, economic and environmentally friendly option. Future research works can focus on evaluating other processes combination with constructed wetland.

Green synthesis of nickel-doped magnesium ferrite nanoparticles via combustion for facile microwave-assisted optical and photocatalytic applications.

NixMg1-xFe2O4(x = 0, 0.2, 0.4, 0.6) nanoparticles were symphonized via combustion with microwave assistance in the presence of Tamarindus indica seeds extract as fuel. Nanoparticles nature, size, morphology, oxidation state, elemental composition, and optical and luminescence properties were analysed using PXRD, FTIR, SEM, EDX, and HRTEM with SAED, XPS, UV-Visible and photoluminescence spectroscopy. PXRD analysis confirms that synthesized nanoparticles are spinel cubic and have a 17-18 nm average crystalline size. Tetrahedral and octahedral sites regarding stretching vibrations were confirmed by FTIR analysis. SEM and HRTEM data it is disclosed that the morphology of synthesized nanoparticles has nano flakes-like structure with sponge-like agglomeration. Elemental compositions of prepared nanoparticles were confirmed through EDX spectroscopy. XPS Spectroscopy confirmed and revealed transition, oxidation states, and elemental composition. The band gap and absorption phenomenon were disclosed using UV-visible spectroscopy, where the band gap declines (2.1, 2, 1.6, 1.8 eV), with increase in nickel NixMg1-xFe2O4(x = 0, 0.2, 0.4, 0.6) doping. Photoluminescence intensity reduces with an incline in nickel doping, was confirmed and disclosed using photoluminescence spectroscopy. Dyes (Methylene blue and Rhodamine B) degradation activity was performed in the presence of NDMF nanoparticles as a photocatalyst, which disclosed that 98.1% of MB dye and 97.9% of RB dye were degraded in 0-120 min. Regarding initial dye concentration and catalyst load, 5 ppm was initiated as the ideal initial concentration for both RB and MB dyes. 50 mg catalyst dosage was found to be most effective for the degradation of MB and RB dyes. In comparison, pH studies revealed that photodegradation efficiency was higher in neutral (MB-98.1%, RB-97.9%) and basic (MB-99.6%, RB-99.3%) conditions than in acidic (MB-61.8%, RB-60.4%) conditions.

Removal of Pb ions using green Co3O4 nanoparticles: Simulation, modeling, adsorption, and biological studies.

Chemical co-precipitation synthesized novel and green cobalt-oxide nanoparticles (Co3O4-NPs) utilizing cobalt nitrate as cobalt precursors. FTIR, Raman, scanning electron microscopy, UV visible, X-ray powder diffraction, and BET was used to analyze the surface characteristics, composition, and morphology, of the NPs. These green Co3O4-NPs were employed to remove Pb ions from simulated wastewater solutions at various pH, adsorbate, temperature, and dose concentrations. At dose 20 mg/L, pH 6.0, 20 mg/L (Pb(II) solution, 25 °C of temperature, and 45 min for equilibrium, nearly 99.44% of Pb ions were removed. To evaluate the kinetic data, four different kinetic equations were used. The data fit the Elovich rate equation better than the other three models. Thermodynamic and isothermal studies were also evaluated, and the maximum adsorption capacity of 450.45 mg/g was observed at 298.15 K. 0.1 M HNO3, and 0.1 HCl were used to regenerate used Co3O4-NPs. Simulation results show the strong correlation of the Co atom in the Co3O4-NPs generates active delocalized surface states, which are energetically most favorable for heavy metal (Pb ions) adsorption and removal, supporting the experimental outcomes. In concluding remarks, green Co3O4-NPs can also be used as an adsorbent to remove Pb ions from wastewater bodies.

Experimental investigation of H3PO4 activated papaya peels for methylene blue dye removal from aqueous solution: Evaluation on optimization, kinetics, isotherm, thermodynamics, and reusability studies.

This investigation is centered on the effectiveness of methylene blue (MB), a cationic dye, adsorbed from an aqueous media by H3PO4 activated papaya skin/peels (PSPAC), with initial pH (2-10), contact time (30-180 min), MB dye concentration (varying from 10 to 50 mg/L), and MB dose (0.1-0.5 gm). The findings show that the best optimal conditions for MB dye removal occur at a 6 pH, 0.3 gm dose of PSPAC adsorbent for 10 mg/L MB dye concentration, with 90 min of contact time. To optimize and validate the extraction efficiency of MB dye, a response surface methodology (RSM) study was conducted using a central composite design (CCD) with a regression model showing R2 = 0.9940. FT-IR spectroscopy shows, CO, and O-H stretching functional groups while FE-SEM is assessed to supervise morphological features of the PSPAC adsorbent. The peak adsorption capacity with 46.95 mg/g for the Langmuir isotherm model conveniently satisfies the adsorption process with R2 = 0.9984 while with R2 = 0.999, a kinetic model, pseudo-second-order, confirms MB dye adsorption by PSPAC adsorbent. Moreover, thermodynamic parameters including ΔGᵒ, ΔH°, and ΔS° were computed and found to be spontaneous and exothermic. Furthermore, regeneration studies employed with NaOH (0.1 M) and HCl (0.1 M) solution media show an acceptable MB removal efficiency consecutive up to three cycles. The study highlights that H3PO4 papaya skin/peel (PSPAC) is an effectual, sustainable, reasonably available biosorbent to remove industrial cationic dyes disposal.

Characterization of municipal solid waste: Measures towards management strategies using statistical analysis.

Implementing unified municipal solid waste management (MSWM) is often difficult due to socio-economic variables. However, spatial GIS models and statistical analysis of solid waste characterized by the weekdays, weekends, and festivals can somewhat mitigate the variance and assist with selecting suitable waste management methods. This paper presents the example of Rajouri, India, to propose a suitable MSWM based on Inverse Distance Weighted (IDW) intensity maps and statistical findings. The considered region was divided into different sample sites based on the local population density, and Municipal Solid Waste (MSW) was collected from four locations in each site on weekdays, weekends, and festivals. Compositional analysis of the MSW was then used to generate spatial IDW models in QGIS 3.22.7 to interpolate MSW generation over the entire area. Finally, statistical analysis was conducted to gain insight into the waste generation and accumulation trends. The results show that Rajouri produces 245 tonnes of waste daily (per capita: 0.382 kg/day) with a large organic fraction compared to other waste categories. Besides, waste generation is observed to increase over weekends and festivals due to increased consumption of material goods. Composting could serve as a vector for municipal solid waste because of its increased organic component and cost constraints. However, further research on the potential segregation techniques for the organic fraction of solid waste is needed.

Zinc oxide nanoparticles adsorb emerging pollutants (glyphosate pesticide) from aqueous solutions.

The present study captures the precipitation synthesis of zinc nanoparticles and modification with alumina and oleic acid. The crystalline size evaluated from the XRD profile of the zinc oxide nanoparticles was 18.05 nm but was reduced to 14.20 and 14.50 nm upon modification with oleic acid and alumina. The XRD spectra also showed evidence of the amorphous nature of zinc oxide nanoparticles and subsequent enhancement upon modification. A porous appearance was observed in the SEM instrumentation but seems to be enhanced by modification. The FTIR absorption spectra of the nanoparticles showed a peak associated with ZnO vibration around 449 cm, but the enhanced intensity was observed due to modification. The prepared ZnO-NPs and the modified samples were good materials for the adsorption removal of glyphosate from water, recording efficiencies above 94% at neutral pH and showing a possible incremental trend with an enhanced period of contact and adsorbent dosage. The adsorbents showed maximum capacity that ranged from 82.85 to 82. 97 mg/g. The adsorption models of Freundlich, Temkin, Dubinin-Radushkevich and BET showed excellent fitness. Results from computational results complemented experimental data and were used to identify the sites for adsorption and characteristics of molecular descriptors for the systems.

Microplastics: Occurrences, treatment methods, regulations and foreseen environmental impacts.

Microplastics are a silent threat that represent a high degree of danger to the environment in its different ecosystems and of course will also have an important impact on the health of living organisms. It is evident the need to have effective treatments for their treatment, however this is not a simple task, this as a result of the behavior of microplastics in wastewater treatment plants due to their different types and nature, their long molecular chain, reactivity against water, size, shape and the functional groups they carry. Wastewater treatment plants are at the circumference of the release of these wastes into the environment. They often act as a source of many contaminations, which makes this problem more complex. Challenges such as detection in the current scenario using the latest analytical techniques impede the correct understanding of the problem. Due to microplastics, treatment plants have operational and process stability problems. This review paper will present the in-depth situation of occurrence of microplastics, their detection, conventional and advanced treatment methods as well as implementation of legislations worldwide in a comprehensive manner. It has been observed that no innovative or new technologies have emerged to treat microplastics. Therefore, in this article, technologies targeting wastewater treatment plants are critically analyzed. This will help to understand their fate, but also to develop state-of-the-art technologies or combinations of them for the selective treatment of microplastics. The pros and cons of the treatment methods adopted and the knowledge gaps in legislation regarding their implementation are also comprehensively analyzed. This critical work will offer the development of new strategies to restrict microplastics.

Understanding the impacts of the COVID-19 pandemic on sustainable agri-food system and agroecosystem decarbonization nexus: A review.

The existing finite natural resources have witnessed unsustainable usage in the past few years, especially for food production, with accompanying environmental devastation and ecosystem damage. Regrettably, the global population and consumption demands are increasing ceaselessly, leading to the need for more resources for food production, which could potentially aggravate the sustainability and ecosystem degradation issues, while stimulating drastic climate change. Meanwhile, the unexpected emergence of the COVID-19 pandemic and some implemented measures to combat its spread disrupted agricultural activities and the food supply chain, which also led to a reduction in ecosystem carbonization. This study sets out to explore policy framework and selected feasible actions that are being adopted during the COVID-19 pandemic, which could potentially reduce the emissions even after the pandemic to promote a resilient and sustainable agri-food system. In this study, we reviewed 27 articles that focus on the current state of the agri-food system in light of the COVID-19 pandemic and its impact on the decarbonization of the agroecosystem. This review has taken the form of a systematic methodology in analyzing the adoption and implementation of various measures to mitigate the spread of COVID-19 on the impact of the agri-food system and reduction in ecosystem degradation. Up to 0.3 Mt of CO2 reduction from the agri-food system alone was reportedly achieved during the first 6 months of the pandemic in 23 European countries. The various adopted measures indicate that the circular economy approach is a panacea to achieve the needed sustainability in the agri-food system. Also, it dictates a need for a paradigm change towards improvement on localized food production that promotes sustainable production and consumption.

COVID-19 transmission, vulnerability, persistence and nanotherapy: a review.

End 2019, the zoonotic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), named COVID-19 for coronavirus disease 2019, is the third adaptation of a contagious virus following the severe acute respiratory syndrome coronavirus in 2002, SARS-CoV, and the Middle East respiratory syndrome virus in 2012, MERS-CoV. COVID-19 is highly infectious and virulent compared to previous outbreaks. We review sources, contagious routes, preventive measures, pandemic, outbreak, epidemiology of SARS-CoV, MERS-CoV and SARS-CoV-2 from 2002 to 2020 using a Medline search. We discuss the chronology of the three coronaviruses, the vulnerability of healthcare workers, coronaviruses on surface and in wastewater, diagnostics and cures, and measures to prevent spreading.

Removing polyfluoroalkyl substances (PFAS) from wastewater with mixed matrix membranes.

Polyfluoroalkyl and perfluoroalkyl (PFAS) chemicals are fluorinated and exhibit complicated behavior. They are determined and highly resistant to ecological modifications that render plants ecologically robust. Thermal stability and water and oil resistance are examples of material qualities. Their adverse consequences are causing increasing worry due to their bioaccumulative nature in humans and other creatures. Direct data indicates that PFAS exposure in humans causes endocrine system disruption, immune system suppression, obesity, increased cholesterol, and cancer. Several PFASs are present in drinking water at low doses and may harm people. These cancer-causing PFAS have caused concern for water bodies all around the globe. Analytical techniques are used to identify and measure PFAS in an aqueous medium (membrane). Furthermore, a deeper explanation is provided for PFAS removal methods, including mixed matrix membrane (MMM) technology. By removing over 99 % of the PFAS from wastewater, MMMs may effectively remove PFAS from sewage when the support matrix contains adsorbing components. Furthermore, we consider several factors affecting the removal of PFAS and practical sorption methods for PFAS onto various adsorbents.

Heart transplantation in a patient with infective endocarditis bridged with Impella 5.5: a case report.

Background: Infective endocarditis (IE) is a feared complication after surgical valve replacement accounting for 10% to 30% of all cases of IE. Our case is unique as we present a decompensated heart failure patient with IE who urgently needed mechanical circulatory support (MCS) to stabilize while IE was treated. We used Impella to bridge him to sterile state before heart transplant was done. This case highlights the importance of different strategies for bridge to heart transplant in decompensated heart failure patients with endocarditis. Case summary: We describe a case of 62-year-old male who initially presented with severe shortness of breath with minimal exertion, weight gain, and lower extremity oedema diagnosed with acute on chronic systolic heart failure (HF) exacerbation (ACC stage D, NYHA class IV). Initial blood cultures and extensive work-up for IE were negative. He continued to decompensate haemodynamically despite inotropic support and the decision was to proceed with durable left ventricular assist device (LVAD) as bridge to orthotopic heart transplantation (OHT). Immediately prior to LVAD implantation, patient's blood cultures became positive for Cutibacterium acnes. Echocardiogram revealed IE on bioprosthetic aortic valve. Patient therefore underwent urgent aortic valve replacement (AVR) and was stabilized with Impella 5.5. Discussion: We highlight a case where MCS with Impella was used as a bridge to transplant in a decompensated HF patient who was septic. Patient was listed for OHT but was found to be septic due to IE and had to undergo AVR to achieve infection source control prior to undergoing heart transplant. Impella was used effectively to stabilize ACC stage D/NYHA class IV patient while he recovered from AVR and endocarditis before his blood cultures cleared up and he was listed for OHT. He successfully underwent OHT after 3 weeks.

Synthesis, characterization, and application of thio-salicylaldehyde schiff base complexes for Cr (VI) adsorption.

This study investigates the effectiveness of a Schiff base derived from thio-carbohydrazide and salicylaldehyde as an adsorbent for Cr(VI) removal from wastewater. The Schiff base demonstrated excellent adsorption capacity and reusability, with high removal efficiency and rapid adsorption kinetics. The results were supported by theoretical density functional theory simulations, which revealed the enhanced dynamic nature of the Schiff base system for heavy metal adsorption. These findings highlight the potential of Schiff base complexes as sustainable and efficient adsorbents for industrial wastewater treatment.

Economic valuation and characterization of heavy metal contamination in Dal Lake Srinagar, Kashmir, India.

Dal Lake, the world-famous tourist attraction has been polluted by allochthonous and autochthonous sources, as a result the heavy metal (HMs) concentrations within the water body has reached the toxic levels which is endangering the lives of the people. A study was carried out during the year 2021 (i) to determine the concentration of HMs (molybdenum: Mo, arsenic: Ar, cadmium: Cd, lead: Pb) at the four designated sites of Dal Lake, and (ii) a public survey (400 persons) involving economic valuation of water body in terms of recreational use and other benefits. The highest values of biological oxygen demand (BOD) and chemical oxygen demand (COD) within the Dal Lake were recorded at site A, which were 31 ± 1.10 mg/l and 76 ± 0.64, respectively. Similarly, maximum nitrate nitrogen was found at site A (865 ± 0.86 µg/l). The highest value of Pb was reported (6.828 ± 0.003 ppb) from site A whereas, the lowest from site B (2.492 ± 0.002 ppb). The mean values of Mo concentrations (in ppb) were found to be 2.538 ± 0.002, 1.703 ± 0.003, 3.627 ± 0.004 and 4.787 ± 0.002 at the four sites respectively. The observed values of HMs (in ppb) were much higher than the permissible values (WHO, 2006) and those reported earlier. A huge amount of money (Rs 16,18,66,000/) is being generated from the floating gardens of Dal Lake, calculated by TCM and CVM methods. During the survey, 68 % of people showed a willingness to pay (WTP) for the restoration of the Dal Lake and improved services (mean value: Rs 62,852.20/). Thus, the monitoring and assessment were done to find out how the Dal Lake contributes to the economy of the state by way of its different services and the major attraction for tourists besides the possible reasons for the deterioration of water quality, in order to find a long-lasting solution for the sustainable conservation of Dal Lake.

Development and life cycle assessment (LCA) of super-oleophobic (under water) and super-hydrophilic (in-air) mesh membrane for oily water treatment.

This paper reports the fabrication, characterization, and environmental impact analysis of a super-oleophobic (under water) and super-hydrophilic mesh membrane for oily water treatment. In order to prepare mesh membrane, Titania nanoparticles (NPs) were spray coated on mesh stainless steel followed by calcination at 500 °C. After that, the Titania-coated mesh membrane was characterized using contact angle goniometry (CA), XRD, FE-SEM, EDX and elemental mapping. The FE-SEM, EDX, elemental mapping and XRD results confirmed that the Titania NPs were successfully coated on the surface of mesh membrane. CA results demonstrated that the prepared mesh membrane is super-hydrophilic and super-oleo phobic under water conditions, making it suitable for oil/water separation. Subsequently, life cycle assessment (LCA) was performed to determine the environmental impacts of Titania NPs-coated mesh membrane fabrication process. LCA results indicate that electricity and nitrogen contributed the most toward the eighteen environmental impact categories considered for this study.

The impact of heavy metal concentrations on aquatic insect populations in the Asan Wetland of Dehradun, Uttarakhand.

This study, centered on the Asan Wetland in Uttarakhand, examines the ecological impact of heavy metals on aquatic insects biodiversity. It highlights the detrimental effects of metals like chromium, mercury, and lead, stemming from natural and anthropogenic sources, on aquatic insects diversity. Aquatic insects, particularly sensitive to water quality, are emphasized as key indicators of environmental health, illustrating the importance of understanding and managing the influences on wetland ecosystems. Wetland ecosystems are vulnerable to various environmental stressors, including pollution from heavy metals. These toxic substances can alter water quality parameters, disrupt nutrient cycling, and negatively impact the biodiversity and ecological balance of the system. This study aimed to evaluate the impact of several heavy metals (namely Cd, As, Cu, Fe, Pb, Ni, Zn, Al, Cr) on the distribution and biodiversity of various aquatic insect species, including Coeleoptera, Diptera, Ephemeroptera, Odonata, Plecoptera, and Trichoptera. The research utilized data collected between November 2021 and October 2022 from specifically chosen sites (S1, S2, S3) within the Asan Wetland in Dehradun, Uttarakhand. After collecting and identifying samples, various statistical (Sorenson, Shannon-Weiner diversity index, Margelef index) and multivariate tests (CCA, PCA, One-way Anova), have been applied to show the effects of these parameters. This study offers significant findings regarding the distribution patterns of heavy metals, the abundance of aquatic insects, and their interconnectedness within the ecosystem of the Asan Wetland. The abundance of aquatic insects, represented by 13 genera belonging to 6 orders, was assessed at three different sites (S1, S2, and S3) within the wetland. It was concluded that the heavy metals concentration and aquatic insects' density increases and decreases vice-versa in monsoon and winter seasons might be due to unfavourable factors. These findings contribute to the understanding of ecological dynamics and potential impacts of heavy metals on aquatic biota in wetland environments.

Equilibrium and kinetic modeling of Cr(VI) removal by novel tolerant bacteria species along with zero-valent iron nanoparticles.

This work describes the study of the removal of a refractory contaminant, i.e., Hexavalent chromium (Cr(VI)) from aqueous systems by a novel adsorbent comprising Cr(VI) tolerant bacteria and zero valent iron nanoparticle (nZVI). A gram-positive, rod-shaped bacteria used in the study were isolated from wastewater (WW) received from the effluent of leather industries. The adsorbents were prepared with bacteria, nZVI alone, and a combination of both. The adsorbent comprising both elements was found to remove Cr(VI) with a higher percentage (93%) and higher capacities (0.58 mg/g) as compared to adsorbent with bacteria (Cr(VI) removal = 63%, qe = 0.163 mg/g) or nanoparticles (Cr(VI) removal = 80%, qe = 0.45 mg/g) alone. The adsorbent worked best at neutral pH, and the removal became saturated after 90 min of incubation. Equilibrium studies with isotherm modeling suggested that the adsorption process follows sips isotherm (R2 = 0.9955), which is expected to bean intra-particle diffusion process before the actual adsorption. Process kinetics was modeled with pseudo-first order, pseudo-second order, and Vermeulen model. The diffusion coefficient determined by fitting the kinetic data to Vermeulen model was found to be 0.0000314 cm2/s. The adsorbent can be tested further for continuous flow processes to find more insights about the usage on a large scale.