Browsing by Author "Usha Pandey"

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Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India
(2009) Jiten Pandey; Usha Pandey
Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) × two treatments (organic farming in open field and organic farming in glasshouse (OFG)) × seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals. © Springer Science+Business Media B.V. 2008.
Anthropogenic drivers shift diatom dominance-diversity relationships and transparent exopolymeric particles production in River Ganga: Implication for natural cleaning of river water
(Indian Academy of Sciences, 2017) Usha Pandey; Jitendra Pandey; Anand V. Singh; Abha Mishra
We studied the relationships among diatom biodiversity, transparent exopolymeric particles (TEP) and water quality at the confluences of four tributaries of River Ganga (Yamuna, Assi, Varuna and Gomti) during low flow. Diatom abundance changed with concurrent shifts in water chemistry with dominance- diversity curves markedly skewed from a log-normal pattern. Canonical correspondence analysis segregated chloride-loving and calcifilous species from N- and P-favoured taxa. Despite pollution-induced reduction of diatom diversity, TEP production continued to rise plausibly due to dominance transference of TEP producers. However, with further increase in nutrient pollution, TEP declined. Since TEP enhances sedimentation removal of carbon, nutrients and heavy metals, the present study confirms one of the fundamental mechanisms that underline the self-purification capacity of River Ganga and has relevance from a biodiversity/river conservation perspective.
Anthropogenically induced shifts in N:P:Si stoichiometry and implications in Ganga River
(Libertas Academica Ltd., 2016) Jitendra Pandey; Shraddha Tripathi; Usha Pandey
Human-induced N:P:Si imbalances and associated shifts in nutrient limitation in Ganga River remain relatively uncertain despite recent studies highlighting its importance. The goal of this watershed-scale study was to investigate the nutrient-limiting status of Ganga River, as influenced by atmospheric deposition (AD) and catchment runoff together with urban–industrial development. AD was highest in middle watershed, where AD of NO3− ranged from 10.56 to 28.93, AD of NH4+ from 4.26 to 15.42, and AD of PO43− from 1.82 to 2.94 kg ha−1 year−1. The results showed that ADcoupled catchment runoff is an important factor, in addition to direct urban–industrial release, causing N:P:Si imbalances that lead to N over P limitation (N:P < 16:1) and Si over N limitation (Si:N < 1) in the river. The skewed N:P:Si ratios observed here may have important effects on phytoplankton/diatom growth and trophic cascades and consequently on river ecology. This study that forms the first report on changing atmosphere–land–water N:P:Si linkages suggests that the current policy on Ganga rejuvenation needs to focus more strongly on cross-domain drivers of stoichiometric imbalances and approaches to minimize them. © the authors, publisher and licensee Libertas Academica Limited.
Atmospheric deposition and land-surface runoff driven nutrient flushing in Ganga River (India)
(Taylor and Francis Ltd., 2020) Jitendra Pandey; Usha Pandey; Anand V. Singh; Deepa Jaiswal; Ekabal Siddiqui; Kavita Verma
Disproportionate addition of nutrients can alter the nutrient stoichiometric balance of surface water bodies. In the present study, we investigated the atmospheric deposition (AD) and runoff-induced nutrient enrichment and N:P stoichiometric shifts in the Ganga River along a 35 km stretch of Varanasi city. The region receives 8–42 kg ha−1 of reactive-N (NO3− + NH4+) and 0.40–3.10 kg ha−1 of PO43- through AD annually. The most polluted Rajghat Site receives ~770.50 tons of reactive-N (Nr) and ~64.50 tons of PO43- annually as AD input in the sub-watershed; and ~25.10 tons of Nr and 2.09 tons of PO43- directly on the water surface. Concentrations of nutrients in surface runoff increased with AD input irrespective of land use. Among land use categories, the runoff nitrate was highest from agricultural catchment while NH4+ and PO43- were highest from urban areas. The study showed that the AD-runoff coupled with additional supplies could substantially alter the overall load and stoichiometric ratios of critical nutrients with a consequent effect on ecological functioning of the river in long-run. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Atmospheric deposition coupled terrestrial export of organic carbon in Ganga River (India): linking cross-domain carbon transfer to river DOC
(Springer Verlag, 2015) Jitendra Pandey; Anand V. Singh; Rachna Singh; Pooja Kaushik; Usha Pandey
The atmosphere–land–water connectivity of dissolved organic carbon (DOC) is not altogether accounted in major rivers of India despite recent researches highlighting its importance. We studied the coupled effect of atmospheric deposition (AD) and local land use on DOC buildup in Ganga River for a period of 6 years. The AD-OC input increased consistently over time and there was over 1.5- to 1.8-fold increase in 2012 relative to 2007. Microbial activity and water soluble organic carbon (WSOC) in sub-catchment and DOC in land surface runoff increased consistently over time along the gradient of AD input. The river DOC showed positive correlation (R2 = 0.24–0.84; p < 0.001) with AD-OC and runoff DOC and WSOC showed positive correlation (R2 = 0.96; p < 0.001) with soil microbial activity. Principal component analysis segregated study sites into four groups demarcating source relationships. Our study, that forms the first report on atmosphere–land–water transfer of organic carbon in Ganga River, suggests that future climate models should include region-specific time series data on changing state of atmosphere– land–water connectivity and associated shift in carbon balance of major rivers for more accurately predicting the climate change drivers. © 2015, The Author(s).
Atmospheric deposition of nutrients shifts carbon capture and storage trends in freshwater tropical lakes in India
(Biotron Institute, 2014) Jitendra Pandey; Usha Pandey
An understanding of ongoing changes in biogeochemistry of carbon (C) as influenced by increasing atmospheric deposition (AD) of nutrients is important for integrated water resource management and for exploring options for balancing C sink and fluxes. To determine whether AD-nutrients would increase phytoplankton production and catchment carbon flushing in lakes, we analyzed NO3-, NH4+ and PO4-3 in atmospheric deposits, microbial biomass and activity in catchment, nutrient and dissolved organic carbon (DOC) in runoff and, phytoplankton production and sediment-C in six freshwater lakes from 1999 to 2008. Although N: P stoichiometry of AD did not change over time, there was over 1.5 fold increase in AD-NO3-, NH4+ and PO4-3overtime. Microbial biomass and activity in catchments and, DOC and nutrients in runoff increased consistently over time. Lake nutrients, DOC, gross primary productivity, chlorophyll a biomass and sediment-C also showed positive relationship with AD-nutrients. The study indicates that rising input of AD-nutrients steer freshwater lakes towards greater productivity, whereas such inputs in catchment enhance microbial processes and consequently runoff DOC flush and the-coupled effects of these may cause long-term shift in water quality and C balance of these ecosystems.
Ecosystem Responses to Pollution in the Ganga River: Key Issues to Address River Management
(Springer Singapore, 2021) Deepa Jaiswal; Usha Pandey; Jitendra Pandey
From over five decades, there has been a rapid increase in pollutant concentration in the Ganga River. Much of the debates about the rising pollution in the rivers have been focused on urban sewage input and its associated increase in biological oxygen demand (BOD). Here, we present an overview of explicit multifactor causation, ecosystem-level shifts, multiform determinants (nutrient stoichiometry, transparent exopolymeric particles (TEP), diatom dominance-diversity linkages, microbial extracellular enzymes (EE), ecological response index (ERI), and ecosystem feedbacks), and alternative response indicators to address shifts in ecosystem functions coupling human perturbations. Based on a critical analysis of available studies/data and emerging trends, we argue that anthropogenic influences on the Ganga River are far more severe than what is being predicted from short-term small-scale studies. At many locations, especially those located downstream of point sources, the river is overstepping its resilience as demonstrated by dissolved oxygen deficit at sediment-water interface and associated feedbacks (denitrification, sediment-P and sediment-metal release). Because in human-impacted rivers eutrophication and metal pollution generally occur simultaneously, the EE, ERI, and TEP-diatom linkages provide novel tools to assess how the human activities might impact ecological functioning and assimilation capacity of the Ganga River. These issues set the stage for understanding and assessing current and possible future changes on which the Ganga River management strategies can be keyed. © Springer Nature Singapore Pte Ltd. 2021.
Effects of COVID-19 lockdown on water quality, microbial extracellular enzyme activity, and sediment-P release in the Ganga River, India
(Springer Science and Business Media Deutschland GmbH, 2022) Madhulika Singh; Usha Pandey; Jitendra Pandey
This study investigates possible improvement in water quality and ecosystem functions in the Ganga River as influenced by COVID-19 lockdown in India. A total of 132 samples were collected during summer-2020 low flow (coinciding COVID-19 lockdown) for water (sub-surface and sediment-water interface) and 132 samples separately for sediment (river bottom and land-water interface) considering 518-km main river stem including three-point sources (one releases urban sewage and the other two add metal-rich industrial effluents) and a pollution-impacted tributary. Parameters such as dissolved oxygen deficit and the concentrations of carbon, nutrients (N and P), and heavy metals were measured in water. Sediment P-release was measured in bottom sediment whereas extracellular enzymes (EE; alkaline phosphatase, FDAase, protease, and β-D-glucosidase) and CO2 emission were measured at land-water interface to evaluate changes in water quality and ecosystem functions. The data comparisons were made with preceding year (2019) measurements. Sediment-P release and the concentrations of carbon, nutrients, and heavy metals declined significantly (p<0.05) in 2020 compared to those recorded in 2019. Unlike the preceding year, we did not observe benthic hypoxia (DO <2.0 mg L−1) in 2020 even at the most polluted site. The EE activities, which declined sharply in the year 2019, showed improvement during the 2020. The stability coefficient and correlative evidences also showed a large improvement in the water quality and functional variables. Positive changes in functional attributes indicated a transient recovery when human perturbations withdrawn. The study suggests that timing the ecosystem recovery windows, as observed here, may help taking management decision to design mitigation actions for rivers to recover from anthropogenic perturbations. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Efficacy assessment of cyanobacterial biofertilizer in maize cropping in indo-gangetic plains
(Nova Science Publishers, Inc., 2017) Usha Pandey; Jitendra Pandey
Increasing demand for safe and contamination free agricultural produce has led organic farming to emerge as a global alternative of chemical fertilizer based agriculture. India is one of the leading countries for certified organic produce and maize is one among the five major cereal crops in the country. Maize is a staple food crop, which serves as food source for a large human population, feed for cattle and raw material for many industries. It has high yield potential and cultivated in almost all the states of India. Maize grains are rich in protein, vitamins (especially vitamin A, nicotinic acid, riboflavin and vitamin E), phosphorus and other nutrients. Bio-fertilizer supplemented organic farming has emerged as an important step towards maintaining soil fertility stability and seed yield. Use of cyanobacterial bio-fertilizer is cost effective and helps maintaining soil health. The present study was undertaken to assess the efficacy of cyanobacterial biofertilizer on overall yield and sustainability of maize production. The randomized block design of the experiment consists of one crop species (Zea mays L.), five treatments (cyanobacterial biomass supplement (CBS), recommended dose of NPK, two independent bacterial inoculums and a control set), three replications and three independent experimental repeat. The results showed that soil amendment with cyanobacterial biomass supported significantly higher plant growth, grain and fodder yield over control and close to that of NPK amended sets. Both the grain and fodder yields increased consistently in the next two cropping supplemented with same level of CBS. The same level of NPK amendment however, did show a marginal decline in grain yield in third year. Although more extensive and repetitive field trials are required, the study provides evidence that cyanobacterial bio-fertilizer can help obtain sustained yield and overcome the constraints of diminishing return observed in chemical fertilizer based agriculture sector. © 2017 by Nova Science Publishers, Inc. All rights reserved.
Enhanced production of biomass, pigments and antioxidant capacity of a nutritionally important cyanobacterium Nostochopsis lobatus
(2008) Usha Pandey; J. Pandey
A diazotrophic cyanobacterium Nostochopsis lobatus was evaluated for enhanced production of biomass, pigments and antioxidant capacity. N. lobatus showed potentially high antioxidant capacity (46.12 μM AEAC) with significant improvement under immobilized cell cultures (87.05 μM AEAC). When a mixture of P and Fe was supplemented, biomass, pigments, nutritive value and antioxidant capacity increased substantially at pH 7.8. When considered separately, P appeared to be a better supplement than Fe for the production of biomass, chlorophyll and carotenoids. However, for phycocyanin, phycoerythrin, nutritive value and antioxidant capacity, Fe appeared more effective than P. Our study indicates N. lobatus to be a promising bioresource for enhanced production of nutritionally rich biomass, pigments and antioxidants. The study also suggests that P and Fe are potentially effective supplements for scale-up production for commercial application. © 2007 Elsevier Ltd. All rights reserved.
Enhanced production of high-quality biomass, δ-aminolevulinic acid, bilipigments, and antioxidant capacity of a food alga nostochopsis lobatus
(2008) Usha Pandey; J. Pandey
The growing interest in natural food has raised the global demand for nutraceuticals. We studied enhanced production of biomass, delta-aminolevulinic acid (δ-ALA), bili pigments and antioxidant capacity of a food alga Nostochopsis lobatus in a full-factorial (three level) design with supplemental Zn, glutamine, and Zn + glutamine in batch culture. Production of biomass, pigments, and antioxidant capacity all were higher under immobilized cell cultures in comparison to free cell cultures. Maximum biomass (2,390 mg dry wt l-1), δ-ALA (2.715 μg mg-1 dry wt h -1), phycocyanin (98.50 mg g-1 dry wt), phycoerythrin (158.0 mg g-1 dry wt), and antioxidant capacity (140.50 μmoles ascorbic acid equivalent capacity g-1 fresh wt) were recorded when Zn and glutamine were supplemented together in the growth medium at pH 7.8. These effects were found to be significantly related to the activities of glutamine synthetase (GSmax: 490.2 nmoles mg protein-1 min -1), glutamate synthase (GOGATmax: 27.0 nmoles mg protein-1 min-1), and glutamate dehydrogenase (GDH max: 159.9 nmoles mg protein-1 min-1). This study shows that N. lobatus could be a promising bioresource for the production of nutritionally rich biomass, δ-ALA, bili pigments, and antioxidants. Use of immobilized cells in batch culture supplemented with Zn and glutamine could be an effective approach for scaling up production for commercial use. © 2008 Humana Press.
Enhanced production of δ-aminolevulinic acid, bilipigments, and antioxidants from tropical algae of India
(2009) Usha Pandey; Jitendra Pandey
We studied the enhanced production of high quality biomass, δ-aminolevulinic acid (δ-ALA), bilipigments, and antioxidants from five tropical blue green algae (cyanobacteria) in a full factorial design using free and immobilized cells in batch culture. Production of nutraceuticals was high in spray dried powder prepared from immobilized cell cultures. Nostochopsis lobatus showed superiority over rest of the species with respect to bilipigments, δ-ALA, nutritive value, antioxidant capacity, and ascorbate oxidase (APX) activity. Antioxidative capacity of phycobiliproteins extracted from these cyanobacteria (121.15 μM TE/g, Nostoc verrucosum to 217.62 μM TE/g, Nostochopsis lobatus) was invariably higher than those observed for higher plant sources and substantially increased under immobilized cell culture condition. Antioxidative enzyme, ascorbate oxidase remained stable in dry food preparations with considerably high activity under immobilized cell preparations (APXmax, 3.40 μmol/min/mg chlorophyll). These observations have important connotations in light of upcoming food and nutraceutical industries in the global market. Use of immobilized cells in batch culture could be an effective approach for scaling up production for commercial use. © The Korean Society for Biotechnology and Bioengineering and Springer-Verlag Berlin Heidelberg GmbH 2009.
Evaluation of air pollution phytotoxicity in a seasonally dry tropical urban environment
(Kluwer Academic Publishers, 1994) Jitendra Pandey; Usha Pandey
This study was conducted in the urban environment of Varanasi, India, to evaluate the plant responses to urban air pollution. Twenty sites were selected in four different zones of the city. At each site, seven woody perennials of same age classes were selected. Out of the four zones (I, II, III and IV), zone IV was used as a reference (control) zone as it received the minimum pollution input. Plant species growing in polluted and control areas were compared with respect to foliar dust load, per cent leaf area injury, leaf area, specific leaf weight and chlorophyll, ascorbic acid, SO42-S and total N concentration in the leaves. Results indicated that the air pollution level in Varanasi causes leaf damage, reduces leaf area, specific leaf weight and chlorophyll, ascorbic acid and total N concentrations in the leaves. Sulphur concentration in leaves increased with increasing level of SO2 in the ambient air. The magnitude of such changes was maximum at the zone receiving maximum pollution load. Carissa carandas was found to be the most sensitive species and Bougainvillea spectabilis, the least. The study shows that the urban air pollution level in Varanasi is detrimental for the growth of plants involved in this study. © 1994 Kluwer Academic Publishers.
Impact of changing atmospheric deposition chemistry on carbon and nutrient loading to Ganga River: Integrating land-atmosphere-water components to uncover cross-domain carbon linkages
(Kluwer Academic Publishers, 2014) Jitendra Pandey; Usha Pandey; Anand V. Singh
Terrestrial contribution of dissolved organic carbon (DOC) to riverine carbon transport remains relatively uncertain despite recent research highlighting its importance. Here we present data on changing state of atmosphere-land-water transfer and associated shift in DOC build-up in Ganga River (India) for a period of 6 years (March, 2007-February, 2013). Although the N:P stoichiometry of atmospheric deposition (AD) showed a declining trend, there was over 1.4 to 1.6-fold increase in AD-NO3 -, 1.5 to 1.8-fold increase in AD-OC and, over 1.5 to 2.2-fold increase in AD-NH4 + and AD-PO4 3- input over time. Water soluble organic carbon and microbial activity in sub-catchments and, DOC and nutrient concentrations in runoff increased consistently over time along the gradient of AD-input. We found a variable but strong linkage between atmospheric deposition and hydrological control of terrestrial carbon and nutrient input to the river. The results showed that the increasing input of AD-nutrients enhance primary production whereas, such input in sub-catchment enhance DOC in runoff and, the coupled effect of these favor DOC build-up in Ganga River at Varanasi. The study that forms the first report establishing trans-boundary drivers of DOC in Ganga River suggests that future climate model should consider large scale inter-regional time series data on changing atmosphere-land-water transfer and associated shift in carbon balance of major rivers for more accurately predicting cross-domain carbon linkages and planning for integrated river basin management. © 2014 Springer International Publishing Switzerland.
Impact of DOC trends resulting from changing climatic extremes and atmospheric deposition chemistry on periphyton community of a freshwater tropical lake of India
(Kluwer Academic Publishers, 2013) Usha Pandey; Jitendra Pandey
Recent measurements have demonstrated unprecedented increase in atmospheric deposition of nutrients in many parts of India. To determine whether atmospheric nutrient inputs would increase phytoplankton growth and catchment dissolved organic carbon (DOC) flushing to constrain benthic algae, we analyzed NO3- and PO4-3 in atmospheric deposits; nutrients and DOC in runoff and lake water and standing crop biomass of phytoplankton and periphyton at Jaisamand Lake of Rajasthan, India. Atmospheric deposition of NO3- (7. 18-29. 95 kg ha-1year-1) and PO4-3 (0. 56-2. 15 kg ha-1year-1) showed a consistently rising trend across the year. Microbial biomass and activity in catchment increased in response to atmospheric deposition. Lake DOC and nutrients showed strong coherence with their terrestrial and atmospheric fluxes. Phytoplankton development showed significant linearity with atmospheric input of nutrients. Air-driven input appeared to have compensated the nutrient constraints to phytoplankton during drought. The N:P stoichiometry of deposition and that of lake water indicated that, although there was a seasonal switchover to N- or P-limitation, phytoplankton were mainly co-limited by N and P due probably to the synergistic effects of combined N + P enrichment in the pelagic zone of the lake. Periphyton standing crop showed inverse relationship with phytoplankton and lake DOC. The study indicated that enhanced phytoplankton development and terrestrial DOC flushing in response to atmospheric nutrient input attenuated light penetration to constrain algal periphyton. We suggests that data on these issues may be considered in developing aquatic ecosystem models to establish future links between changing air-water-land interactions and associated shifts in lake ecosystem functioning for more accurately predicting climate change drivers and designing integrated lake basin management strategies. © 2012 Springer Science+Business Media B.V.
Integrating atmospheric deposition-driven nutrients (N and P), microbial and biogeochemical processes in the watershed with carbon and nutrient export to the Ganga River
(Springer, 2020) Ekabal Siddiqui; Jitendra Pandey; Usha Pandey; Vibha Mishra; Anand Vikram Singh
There has been considerable debate on how atmospheric deposition (AD) in the watershed alters the supply of dissolved organic carbon (DOC) to river and coastal ecosystems. Here we show how AD-N and –P in the Ganga River Basin (GRB) drives the delivery of DOC. We conducted three sets of studies, a 3 year (2016–2018) in situ trial, a 5 year (2014–2018) soil-spray experiment and a decadal-scale (2009–2018) in situ coupled pot-culture study to show how AD-N and –P stimulates soil microbial activity and consequently enhances the DOC export to the Ganga River. The AD-input increased overtime, and on an average, the basin receives ~ 1.55 Tg Nr and ~ 0.088 Tg P annually. Our results show that AD–N and –P increases soil microbial biomass (Cmic), substrate-induced respiration (SIR), FDAase and β-D-glucosidase activity to enhance water-soluble organic carbon (WSOC) in the watershed. We found significant correlations (r = 0.83–0.93; p < 0.001) of Cmic, SIR, enzyme activities, WSOC and DOC with AD–N and –P in the watershed. Although the land use was found to be the dominant contributor of variations, the AD-input did appear an important driver enhancing the delivery of DOC. The runoff flux of DOC was found to the highest for built-up land (that include urban wash) followed by wasteland, grassland, agricultural land, scrubland, mixed forest and deciduous forest. The study has relevance understanding the mechanism of AD-driven DOC delivery and designing an action plan for integrated river basin management (IRBM). © 2020, Springer Nature Switzerland AG.
Integrating resilience with functional ecosystem measures: A novel paradigm for management decisions under multiple-stressor interplay in freshwater ecosystems
(John Wiley and Sons Inc, 2021) Deepa Jaiswal; Usha Pandey; Vibha Mishra; Jitendra Pandey
Moving beyond monitoring the state of water quality to understanding how the sensitive ecosystems “respond” to complex interplay of climatic and anthropogenic perturbations, and eventually the mechanisms that underpin alterations leading to transitional shifts is crucial for managing freshwater resources. The multiple disturbance dynamics—a single disturbance as opposed to multiple disturbances for recovery and other atrocities—alter aquatic ecosystem in multiple ways, yet the global models lack representation of key processes and feedbacks, impeding potential management decisions. Here, the procedure we have embarked for what is known about the biogeochemical and ecological functions in freshwaters in context of ecosystem resilience, feedbacks, stressors synergies, and compensatory dynamics, is highly relevant for process-based ecosystem models and for developing a novel paradigm toward potential management decisions. This review advocates the need for a more aggressive approach with improved understanding of changes in key ecosystem processes and mechanistic links thereof, regulating resilience and compensatory dynamics concordant with climate and anthropogenic perturbations across a wide range of spatio-temporal scales. This has relevance contexting climate change and anthropogenic pressures for developing proactive and adaptive management strategies for safeguarding freshwater resources and services they provide. © 2021 John Wiley & Sons Ltd.
Metal Contamination in Seven Tributaries of the Ganga River and Assessment of Human Health Risk from Fish Consumption
(Springer Science and Business Media, LLC, 2019) Ekabal Siddiqui; Kavita Verma; Usha Pandey; Jitendra Pandey
We investigated the distribution of Zn, Cu, Ni, Pb, Cr, and Cd in water, sediment, and two dietary fish (an omnivore, Labeo rohita and a benthic carnivore, Clarias batrachus) and potential health risk to human consumers during summer low flow (2017–2018) at 28 sites across 7 tributary confluences of the Ganga River. We selected Devprayag, an upper reach site, as a reference for data comparison. We found significant spatial variations in the distribution of study metals and the concentrations remained higher in tributaries, confluences, and downstream cities. The pollution load index showed all sites except Devprayag in the polluted category. Ecological risk analysis indicated 1 site with very high risk, 7 with considerable risk, and 10 with moderate-risk category. The Zn did appear the most, and Cd the least accumulated metal in the fish. The metal accumulation was higher in C. batrachus. The levels of Cd, Cr, and Pb in the study fishes were higher compared with the international standards. The health risk analysis indicated safe levels for individual metals except for Cd where the target hazard quotient (THQ) did exceed 1 for C. batrachus at the Ramganga and Varuna confluences. When all metals were considered, the THQ was > 1 (> 2 for C. batrachus), indicating the full possibility of adverse health effects to human consumers. Our study highlights the importance of tributaries in creating a mosaic of metal-rich habitats in the Ganga River and food chain associated with a health risk to human consumers. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
N:P stoichiometry and transparent exopolymeric particles buffer ecological impacts of nutrients in the Ganga River: a mesocosm study
(Taylor and Francis Ltd., 2018) Jitendra Pandey; Usha Pandey; Anand V. Singh; Deepa Jaiswal; Ekabal Siddiqui; Kavita Verma
We investigated the possible drivers of the N:P stoichiometric shift and its relationship with micro-algal production of transparent exopolymeric particles (TEP) along a 35 km gradient of the Ganga River. The objective was to evaluate if the trade-off between N:P stoichiometry and production of TEP helps in maintaining water quality of the river. Mesocosm experiments were conducted to examine N:P-TEP linkages and its role in turbidity removal. In situ measurements did not show Si to be a limiting nutrient (N:Si < 1.3). The TEP production increased with decreasing N:P ratio and peaked at N:P::6:1 with dominance of Aulacosira granulata and Fragilaria intermedia. Settling efficiency, turbidity removal and sedimentation of TEP, biogenic silica (BSi) and biomass all increased with decreasing N:P ratio proportionately to the amount of TEP produced in the mesocosm. The study demonstrates that trade-off between N:P stoichiometry and the production of TEP generates feedback to buffer the ecological impacts of nutrient pollution. © 2018 Informa UK Limited, trading as Taylor & Francis Group.
Point source-driven seasonal hypoxia signals habitat fragmentation and ecosystem change in River Ganga
(Indian Academy of Sciences, 2019) Jitendra Pandey; Deepa Jaiswal; Usha Pandey
[No abstract available]