Browsing by Author "Mukherjee, Santanu"

In this review, we present the environmental perspectives of the viruses and antiviral drugs related to SARS-CoV-2. The present review paper discusses occurrence, fate, transport, susceptibility, and inactivation mechanisms of viruses in the environment as well as environmental occurrence and fate of antiviral drugs, and prospects (prevalence and occurrence) of antiviral drug resistance (both antiviral drug resistant viruses and antiviral resistance in the human). During winter, the number of viral disease cases and environmental occurrence of antiviral drug surge due to various biotic and abiotic factors such as transmission pathways, human behaviour, susceptibility, and immunity as well as cold climatic conditions. Adsorption and persistence critically determine the fate and transport of viruses in the environment. Inactivation and disinfection of virus include UV, alcohol, and other chemical-base methods but the susceptibility of virus against these methods varies. Wastewater treatment plants (WWTPs) are major reserviors of antiviral drugs and their metabolites and transformation products. Ecotoxicity of antiviral drug residues against aquatic organisms have been reported, however more threatening is the development of antiviral resistance, both in humans and in wild animal reservoirs. In particular, emergence of antiviral drug-resistant viruses via exposure of wild animals to high loads of antiviral residues during the current pandemic needs further evaluation.

Arsenic (As), a geogenic legacy pollutant can be present in environmental matrices (water, soil, plants, or animal) in two redox states (As(III) or As(V)). In the present study, charged mono- and di-amino functionalized triethoxy and methoxyorganosilane (TT1 and TT2- 1% and 5%) were impregnated with quartz sand particles for the treatment of As polluted water. Spectroscopic characterization of organosilane treated sand (STS) indicated the co-existence of minerals (Mg, Mn, Ti), amide, and amidoalkyl groups, which implies the suitability of silanized materials as a metal(loids) immobilization agent from water. Changes in peaks were observed after As sorption in Fourier thermal infrared and EDS images indicating the involvement of chemisorption. Batch sorption studies were performed with the optimized experimental parameters, where an increased removal (>20% for TT2–1% and >60% for TT1–1%) of As was observed with sorbate concentration (50 µg L⁻¹), temp. (25 ± 2 ºC) and sorbent dosages (of 10 g L⁻¹) at 120 min contact time. Among the different adsorbent dosages, 10 g L⁻¹ of both TT1 and TT2 was selected as an optimum dosage (maximum adsorption capacity ≈ 2.91 μg g⁻¹). The sorption model parameters suggested the possibility of chemisorption, charge/ion-dipole interaction for the removal of arsenate.

The concept of natural attenuation of environmental contaminants has been evolved through the harnessing of natural clean up processes (volatilization, biodegradation, sorption, bioaccumulation, dilution, precipitation, dispersion, etc.) for the aquatic and terrestrial ecosystems. Although several researches have been conducted in the last few decades on several aspects (geochemical parameters, performance evaluation, isotope labelling approaches, environmental biotechnology, etc.) of the natural decontamination technologies, a focused overview on its significance for performance-based monitoring and risk assessment of sustainable remediation measures are rare in the literature. In this chapter, the basic science of the water quality treatment, occurrence/fate, and contaminant biodegradation has been discussed along with the mobility and biological detoxification of pollutants. The microbial diversity surrounding the contaminant plume and mechanism of contaminant removal have been elucidated along with special emphasis on the response of the microbial communities toward various kinds of pollutant dynamics. Microbial community shifts in response/vicinity of the contaminated area within a natural wetland ecosystem have also been documented to explore the metabolic network of ecological interactions based on microbial population dynamics. Moreover, a critical assessment on the state-of-the art removal techniques and rate of dissipation of natural contaminants has been presented. Furthermore, the present chapter highlights the major pollutant detoxification pathways and their impact on groundwater flow regime.

The sustainability assessment of bioeconomy value chains among the conceptual tools and performance-based regulations of environmental life-cycle assessment has emerged as a potential important sustainable growth strategy over the past decades. The sustainability pillars of bioenergy-based network system facilitate innovation-driven and support-based policy framework models, which provide overall impact assessment and comprehensive comparison of the environmental performance aspects. This chapter sets out to propose a more comprehensive and complete analysis of life-cycle assessment (LCA) data models to map the pathways of sustainable transition in the context of environmental assessment to bridge the knowledge gaps through the integration of life-cycle inventory and performance reference points based upon operational bridging boundary objects. The present chapter also discusses and addresses the strategy-based key challenges for the successful implementation and alignment of sociotechnical shared concepts through pathways of evaluation and standard context-specific social LCA (sLCA). We suggest an establishment of local and national level cause-effect relationship considering the active and social bioeconomy network system in regional indicators and indices. Additionally, we have emphasized the future perspectives and research needs for environmental and social life-cycle sustainability impact assessment under the analytical role of social inventory and transition governance assessment phase.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a neoteric virus belonging to the beta coronavirus class has created a global health concern, responsible for an outbreak of severe acute respiratory illness, the COVID-19 pandemic. Infected hosts exhibit diverse clinical features, ranging from asymptomatic to severe symptoms in their genital organs, respiratory, digestive, and circulatory systems. Considering the high transmissibility (R0: ≤6.0) compared to Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV, the quest for the clinical development of suitable antiviral nanotherapeutics (NTPs) is incessant. We are presenting a systematic review of the literature published between 2003 and 2020 to validate the hypothesis that the pharmacokinetics, collateral acute/chronic side effects of nano drugs and spike proteins arrangement of coronaviruses can revolutionize the therapeutic approach to cure COVID-19. Our aim is also to critically assess the slow release kinetics and specific target site chemical synthesis influenced competence of NTPs and nanotoxicity based antiviral actions, which are commonly exploited in the synthesis of modulated nanomedicines. The pathogenesis of novel virulent pathogens at the cellular and molecular levels are also considered, which is of utmost importance to characterize the emerging nano-drug agents as diagnostics or therapeutics or viral entry inhibitors. Such types of approaches trigger the scientists and policymakers in the development of a conceptual framework of nano-biotechnology by linking nanoscience and virology to present a smart molecular diagnosis/treatment for pandemic viral infections.

Groundwater is under heavily threat owing to enormous infilteration of dairy farm originated wastewater into it. The anoxic environment in the groundwater due to mixing of organic rich wastewater can produce significant alterations in the groundwater quality. It is therefore necessary to treat such wastewaters before discharging to surrounding areas. Therefore, in this study we evaluated a hybrid constructed wetland (CW) system(40 m² area) consisting of three beds, i.e. Vertical (16 m²) – Horizontal (18 m²) – Vertical (6 m²) connected in series for the treatment of dairy farm wastewater under typical high humid climate in northern India. Tropical perennial plant such as Arundo donax L. was grown on both vertical beds, whereas Hibiscus esculentus L. and Solanum melongena L. were grown on the horizontal bed of the system.The average purification of TSS, BOD3, total N, and P was significant (p < 0.05) in HF bed and recorded as 92.2 ± 6.1, 95 ± 3.8, 83.6 ± 9.0 and 86.1 ± 10.0% respectively.The average load of BOD3, total N, and P in the influent and effluent was recorded (with no significant differences, p > 0.05) as 7.0 ± 7.17, 1.9 ± 0.7, 0.72 ± 0.5 g m⁻² day⁻¹and 0.3 ± 0.2, 0.3 ± 0.2 and 0.04 ± 0.01 g m⁻² day⁻¹ respectively.The average values of total biomass content of Arundo donax L. were differed significantly and recorded as 0.31 ± 0.06, 0.43 ± 0.17, and 0.43 ± 0.16 g g⁻¹ fresh wt. in control, VF-1, and VF-2 respectively. Therefore, the hybrid CW system can be efficiently used for the treatment of dairy farm wastewater with implications on groundwater and health. Future research may focus on performance analysis of upgraded combined anaerobic reactor and hybrid CW system planted with series of macrophytes for on-site treatment of high strength dairy farm wastewater in tropical regions.

The provenance, preponderance, mobilization/export potential, and environmental health effects of charred residues have been reviewed and discussed in the context of decoupling of biogeochemical DOC (and DON) cycling. The present review suggests that high anthropogenic inputs and enrichment of marine sediments by bulk terrigenous DOC (δ¹³C ~ −20‰ to −25‰) lead to high DOC/DON ratios (≥10), which correlate with seasonal hydrology and diagenetic events. The stability of refractory residues like pyrrole for black nitrogen (BN) and aromatic hydrocarbons for (BC) under pedogenic and diagenetic processes needs to be addressed, considering time lags between production and resuspension events. A variation in absolute values of δ¹⁵N (2.0 to 7.0‰) in organically sequestered marine sediments indicates complex sources of various nitrogen-enriched organic carbon (OC) and dynamic erosion processes. These natural events are signified by an OC/DBN ratio of 13.3 ± 3.5, often explained by variations in precursor organic materials. Complex biogeochemical evolution at forest and agricultural ecosystem levels, coupled with anthropogenic influences, renders δ¹⁵N values between −10 and 10‰, which are lower than in marine ecosystems (6–10‰). This article focuses on the interrelationship between DBC and DBN, their global features relative to transport and movement to aquatic bodies, and current methodologies that specifically explore aquatic and terrestrial cycling of DBC/DBN. The review also takes into account critical research gaps and highlights the challenges and opportunities for research on BC and BN dynamics in the environment. The quantitative contribution of BC and BN in the DOC of the hydrosphere and the corresponding pathway of DBC may be studied further to have more insight into the distribution of dissolved matter in the global ocean system.

Arsenic (As), a geogenic and extremely toxic metalloid can jeopardize terrestrial and aquatic ecosystems through environmental partitioning in natural soil-water compartment, geothermal and marine environments. Although, many researchers have investigated the decontamination potential of different mesoporous engineered bio sorbents for a suite of contaminants, still the removal efficiency of various pyrolyzed agricultural residues needs special attention. In the present study, rice straw derived biochar (RSBC) produced from slow pyrolysis process at 600 °C was used to remove As (V) from aqueous medium. Batch experiments were conducted at room temperature (25 ± 2 °C) under different initial concentrations (10, 30, 50, 100 μg L⁻¹), adsorbent dosages (0.5–5 μg L⁻¹), pH (4.0–10.0) and contact times (0–180 min). The adsorption equilibrium was established in 120 min. Adsorption process mainly followed pseudo–second order kinetics (R² ≥ 0.96) and Langmuir isotherm models (R² ≥ 0.99), and the monolayer sorption capacity of 25.6 μg g⁻¹ for As (V) on RSBC was achieved. Among the different adsorbent dosages and initial concentrations used in the present study, 0.2 g L⁻¹ (14.8 μg g⁻¹) and 100 μg L⁻¹ (13.1 μg g⁻¹) were selected as an optimum parameters. A comparative analysis of RSBC with other pyrolyzed waste materials revealed that RSBC had comparable adsorption ability (per unit area). These acidic groups are responsible for the electron exchange (electrostatic attraction, ion-exchange, π–π/n-πinteractions) with the anionic arsenate, which facilitates optimum removal (>60%) at 7 < pH < pHPZC. The future areas of research will focus on decontamination of real wastewater samples containing mixtures of different emerging contaminants and installation of biofilter beds that contains different spent adsorbents/organic substrates (including biochar) for biopurification study in real case scenario.

Antineoplastics (anticancer agents) i.e. alkylating and non-alkylating agents, topoisomerase inhibitors etc. are classified as the contaminants of emerging concern due to growing concern about environmental health degradation. Such cytostatic agents contain a suit of functional groups (i.e. folic acid/purine/pyrimidine/nitrogen analogues), which render their complex chemistry and determine partitioning in the aquatic systems. A systematic review of the recent literature published between 2009 and 2020 has been presented to validate the hypothesis that the environmental fate, distribution, and removal aspects of chemotherapeutic agents depend largely on the structural orientation, environmental (and genetic) factors, and degree of ionization. The key knowledge gaps on the current challenges and opportunities of research trends of cytostatic drugs (and their derivatives) in the environment have been identified and critically discussed. This review provides an overview of risk assessment of pyrimidine antimetabolites and topoisomerase inhibitors, which is need of the hour considering their increasing consumption and state-of-the-art analytical detection. The main focus of the review is that a cocktail mixture of tamoxifen, 5-fluorouracil and other active metabolites of polar, water soluble antineoplastic agents may have the accumulation effect on the aquatic species. They can spread drug resistance via their interaction with some kinases.

The lockdown during COVID-19 pandemic has converted the world into new experimental laboratories, which may reveal temporal or spatial comparative analysis data. However, some startling information is gathered in terms of reduced premature mortality cases associated with air and water quality improvement, enhanced e-learning on a broader platform, work from home, and successful e-health. The decline in vehicular density on roads and congestion leads to reduced energy consumption and associated greenhouse gases (GHG) and other pollutants emission. The lockdown has also been identified as a possible emergency measure to combat severe air pollution episodes. Similarly, industrial pollution has been recognized as one of the primary causes of water resource pollution and would, therefore, bring change in policy vis-à-vis groundwater pollution control. Our findings suggest that the results of successful e-learning and work from home would be a permanent shift from conventional modes in the near future due to a drastic reduction in socio-economic cost. Our critical analysis also highlights that with such temporary lockdown measures acute/chronic ill-effects of anthropogenic perturbations on planet earth can be effectively estimated through sociocultural, socioeconomical and socio-political/sociotechnological nexus.

There is an increasing trend of developing various low-cost grafted natural amino polysaccharides for the biosorptive removal of noxious dye effluents like Malachite green (MG) and anionic Reactive Red–195 (RR-195) dyes from aqueous solution. Chemically cross-linked chitosan microsphere (CTS-HMP), a promising non-toxic biosorbent possessing high charge density and thermal stability was prepared by using hexametaphosphate as ionic cross-linker. Batch biosorption experiments were carried out under different temperatures (298, 308 and 318 K), pH (2.0–10.0), initial concentrations (25–250 mg L⁻¹), adsorbent dosage (0.01–0.1 g) and contact times (0–180 min) to understand the optimum experimental conditions and simultaneously evaluate the adsorption isotherms and kinetics of CTS-HMP. Biosorption equilibrium was established in 120 and 60 min for MG and RR-195 removal process. The pseudo-equilibrium process was best described by the pseudo-second-order kinetic (R² ≥ 0.98), Freundlich and Temkin isotherm model (R² ≥ 0.90). The removal rate of MG and RR-195 gradually increased (69.40 and 148 mg g⁻¹) at 250 mg L⁻¹ of initial concentration till 100 and 50 min of contact period in a single contaminant system, though the removal efficiency of acid dye was ~2 times higher compared to basic dye under optimum conditions (p < 0.05; t-test). Thermodynamic parameters indicated exothermic (MG) and endothermic (RR-195) nature of spontaneous dye removal. The activation energy of sorption (Ea) was <50 kJ mol⁻¹ which highlighted the importance of physical adsorption process. Therefore, the obtained results clearly validate the sustainable utilization of CTS-HMP as a promising functionalized chitosan microparticles/agent for removing dye effluents from the contaminated aqueous phase.

There is an increasing trend of developing various low-cost biogenic sorbents for the efficient and economical removal of noxious metals . Curry leaf powder (CLP), a promising non-toxic biosorbent containing several bioactive compounds was prepared by the pulverization of the dried leaves for the effective removal of Lead (Pb) and Cadmium (Cd). Various batch sorption experiments were carried out under constant temperature (25 °C), different pH (4.5–10.5), initial concentrations (50–200 mg L⁻¹), adsorbent dosages (0.10–0.40 g) and contact times (0–60 min) to understand the optimum experimental conditions and simultaneously evaluate the adsorption isotherms and removal kinetics of CLP. Adsorption equilibrium was established in less than an hour interval (50 min). The pseudo-equilibrium process was best described by the pseudo-second-order kinetic (R² ≥ 0.99), Freundlich and Langmuir isotherm model (R² ≥ 0.94). The removal rate of Pb and Cd gradually increased (15.7 and 12.7 mg g⁻¹ for Pb and Cd) at 100 mg L⁻¹ of initial concentration till 60 min of contact period in a single contaminant system, the effect was non-significant for multiple adsorbent dosage systems (p > 0.05; t-test) though. The regeneration potential of the exhausted biosorbent was excellent upto 5 cycles with the better efficiency observed for Pb. The obtained results explicitly validated the probable utilization of CLP as a promising green adsorbent for metal removal . Future study may highlight the decontamination aspects of emerging contaminants with such green bio sorbents in large scale as well as mimicing the stomach conditions.

Metals pollution pose a serious problem to environmental and human health, if not effectively removed from wastewater using different state-of-the-art treatment technologies. This study investigated the phase distribution of copper (Cu), lead (Pb), zinc (Zn), chromium (Cr) and cadmium (Cd) in wastewater and sludge samples collected from domestic wastewater treatment plant (DWTP), upflow anaerobic sludge blanket (UASB), and downflow hanging sponge (DHS) reactor systems. Sludge from the UASB and DHS contained predominantly reducible fractions of Zn and Cd and oxidizable fractions of Cu, Cr, and Pb. A characteristic bioavailability sequence was Zn > Cu > Cr > Pb > Cd, with significant differences in dissolved fractions among operational modes. Metal concentrations (solid fractions) were substantially high in the DWTP water, and in UASB and DHS systems (dissolved fractions). Pb, Cr and Cd were strongly associated with the solid phase in the final polishing units (FPU) of the DHS system after treatment, indicating binding and removal (∼75–90%) of metals with particulates. MINTEQA2 calculations indicated that Zn was the most readily available metal in free form in all of the systems, with a general order of ZnDWTP > ZnUASB-DHS > PbDWTP > CdUASB-DHS > PbUASB-DHS > CuDWTP > CuUASB-DHS. Overall, metals in the UASB-DHS showed higher binding potential with coexisting ions, mainly anions like carbonates, hydroxyls, and bicarbonates. Non-anion fractions were more prevalent in DWTP samples. Sorption coefficients indicated that metal bioavailability decreases during the treatment in sludge samples, but increases in case of the wastewater samples, which means the treatment process affects metal phase distribution. In general, the selection of wastewater treatment processes should not be solely based on total metal removal efficiency, but also on their potential to promote the most desirable phase distributions.

Biochar was produced from wheat straw (Triticum aestivum), rice straw (Oryza sativa), and kitchen waste at varying pyrolysis temperatures (300°C–700 °C). The biochars were screened depending on their production and physicochemical properties for the adsorptive removal of arsenic (As). The morphological analysis by Field emission scanning electron microscope revealed a porous biochar surface. Spectroscopic characterization of biochars indicated the co-existence of minerals, carboxyl, carbonyl, amide, and hydroxyl groups, which implies the suitability of biochar to immobilize metal (loid)s from soils. Changes in peaks were observed in Fourier-transform infrared and X-ray diffraction images after As sorption indicating the involvement of chemisorption. The thermogravimetric analysis and a low H/C value derived from the CHNS analyzer confirmed the high stability of biochar. The BET analysis was used to estimate the surface areas of wheat straw (15.8 m² g^-1), rice straw (12.5 m² g^-1), and kitchen waste (2.57 m² g^-1) -derived biochars. Batch sorption studies were performed to optimize experimental parameters for maximum removal of As. Maximum removal of As was observed for wheat straw-derived biochar (pyrolyzed at 500 °C) at 8 mg L⁻¹ initial concentration (IC), 7.5 % dose, 25 °C temperature, and 60 min contact time (83.7 ± 0.06 %); in rice straw-derived biochar (pyrolyzed at 500 °C) at 8 mg L⁻¹ IC, 7.5 % dose, 25 °C temperature, 90 min contact time (83.6 ± 0.37 %); and in kitchen waste-derived biochar (pyrolyzed at 500 °C) at 8 mg L⁻¹ IC, 5 % dose, 25 °C temperature, 60 min contact time (76.7 ± 0.16 %). The sorption model parameters suggested the possibility of chemisorption, physisorption, diffusion, and ion exchange for the removal of As. Therefore, it could be recommended to farmers that instead of disposing or burning straws and waste openly, they could adopt the process of charring to generate livelihood security and mitigation of geogenic contaminants from the soil/water dynamic systems.

Geopolymers are the inorganic polymers containing aluminosilicate materials in their backbone and are produced from geopolymerization process at ambient or controlled temperature involving alkali activators and balanced proportion of solid silica/aluminium precursor materials. Geopolymeric binders have excellent surface morphology, mechanical strength, and building material properties depending on different origin of sources facilitated by hydrothermal synthesis and solidification/stabilization reactions of inorganic polymers. We present a systematic review of the literature published between 1991 and 2020 to critically analyze the structural chemistry, synthesis and environmental applications of geopolymers and have thoroughly discussed the relevant state-of-the art experimental results to have more insight on the metal immobilization potential of geopolymers. Our aim is also to critically assess the different isotherm and kinetic models to illustrate the different mechanisms for the effective waste management strategies of different geopolymer binders by spontaneous, endothermic and entropy driven thermodynamic metal entrapment process. Therefore, the present review bridges the knowledge gap to throw light on the source of various materials commonly applied to the material/bio based synthesis of geopolymer materials which have direct impact on the geopolymerization process. Such types of approaches trigger the environmentalists and policymakers in the development of a conceptual framework on green sustainable aluminosilicate based adsorbents, which facilitate better waste management by physical entrapment, chemical bonding and/or ligand exchange reactions.

There is a dire necessity of developing low cost waste water treatment systems, for the efficient removal of noxious heavy metals (and metalloids) such as Arsenic (As) and Cadmium (Cd). Magnetic biopolymer (CABs-MO) was synthesized by the entrapment of nanocrystalline MnO2 in the polymeric microcapsules of calcium alginate (CABs). Batch experiments were conducted under constant pH (6.5), temperature (25^OC), different initial concentrations (30–300 mg L⁻¹) and contact times (0–48 h) to study the adsorption isotherms and removal kinetics of pristine (CABs) and hybrid biopolymer (CABs-MO) for the removal of As and Cd. The pseudo-equilibrium process was mathematically well explained by the pseudo-second-order kinetic (R² ≥ 0.99) and Langmuir isotherm model (R² ≥ 0.99) with the highest monolayer sorption capacity of 63.6 mg g⁻¹ for Cd on CABs-MO. The As removal rate was maximum up to 6.5 mg g⁻¹ after 12 h of contact period in a single contaminant system than in the mixed contaminant (As + Cd) system (0.8 mg g⁻¹), though the effect was non-significant for Cd (p < 0.05; t-test). The performance of the 10 mM HCl as a regenerating agent was superior (for As in comparison to Cd, p < 0.05; t-test) compared to distilled water (DW) through three to five regeneration cycles. Therefore, the obtained results clearly validate the feasibility of CABs-MO as a potential promising adsorbent for removing metal contaminants from the wastewater. Further research is required to study the decontamination of emerging contaminants with such novel composite beads characterized by varied physico-chemical properties.