| 61. |
- Biswas, Ashis, et al.
(författare)
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Surface complexation modeling of temporal variability of arsenic in groundwater : Estimating the role of competing ions in the mobilization processes
- 2013
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Konferensbidrag (refereegranskat)abstract
- This study investigates the relative roles of different competing ions on the mobilization of arsenic (As) by surface complexation modeling of As rich groundwater in the aquifer of Bengal Basin. Two sets of piezometers, installed at different depths of the shallow aquifer (<50 m), have been monitored for As and other relevant hydrogeochemical parameters over a period of 20 months. The potentiality of two different surface complexation models (SCM), developed for ferrihydrite and goethite has been explored to account for the observed temporal variation in As(III) and As(V) concentration in groundwater. The SCM for ferrihydrite appears as the better predictor for the observed variation in both As(III) and As(V) concentration. It is estimated that among the competing ions PO43- is the major competitor of As(III) and As(V) adsorption into Fe oxyhydroxide and competing ability of the ions decreases as PO43- >> Fe(II) > H4SiO4 = HCO3-. The result of sensitivity test indicates that the competition of PO43- with As for the adsorption sites might already reach nearly to the stage of maxima. It is also shown that a slight increase or decrease in pH can have overwhelming effect on the mobility of As(III) and As(V) by changing their concentration oppositely. It appears that only the reductive dissolution of Fe oxyhydroxide cannot explain the observed high As concentration in the groundwater of Bengal Basin. In absence of potential competition for the adsorption sites, As released due to reductive dissolution of Fe oxyhydroxide would have been re-adsorbed into the residual Fe phases. This study suggests that the reductive dissolution of Fe oxyhydroxide followed by competitive ion exchange with the aquifer sediment is the processes conducive for As enrichment in groundwater of the sedimentary aquifers.
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| 62. |
- Biswas, Ashis, et al.
(författare)
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Testing tubewell platform color as a rapid screening tool for arsenic and manganese in drinking water wells
- 2012
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46, s. 434-440
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Tidskriftsartikel (refereegranskat)abstract
- A low-cost rapid screening tool for arsenic (As) and manganese (Mn) in groundwater is urgently needed to formulate mitigation policies for sustainable drinking water supply. This study attempts to make statistical comparison between tubewell (TW)platform color and the level of As and Mn concentration in groundwater extracted from the respective TW (n = 423), to validate platform color as a screening tool for As andMnin groundwater. The result shows that a black colored platform with 73% certainty indicates that well water is safe fromAs, while with 84% certainty a red colored platform indicates that well water is enriched with As, compared to WHO drinking waterguideline of 10 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 79%, 77%, and 81%, respectively.However, the certainty values become 93% and 38%, respectively, for black and redcolored platforms at 50 μg/L, the drinking water standards for India and Bangladesh. The respective efficiency, sensitivity, and specificity are 65%, 85%, and 59%. Similarly for Mn, black and red colored platform with 78% and 64% certainty, respectively, indicates that wellwater is either enriched or free from Mn at the Indian national drinking water standard of 300 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 71%, 67%, and 76%, respectively. Thus, this study demonstrates that TWplatform color can bepotentially used as an initial screening tool for identifying TWs with elevated dissolved As andMn, tomake further rigorous groundwater testing more intensive and implement mitigation options for safe drinking water supplies.
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| 63. |
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| 64. |
- Bundschuh, Jochen, et al.
(författare)
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Medical geology in the framework of the sustainable development goals
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 581, s. 87-104
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to geogenic contaminants (GCs) such as metal(loid)s, radioactive metals and isotopes as well as transuraniums occurring naturally in geogenic sources (rocks, minerals) can negatively impact on environmental and human health. The GCs are released into the environment by natural biogeochemical processes within the near-surface environments and/or by anthropogenic activities such as mining and hydrocarbon exploitation as well as exploitation of geothermal resources. They can contaminate soil, water, air and biota and subsequently enter the food chain with often serious health impacts which are mostly underestimated and poorly recognized. Global population explosion and economic growth and the associated increase in demand for water, energy, food, and mineral resources result in accelerated release of GCs globally. The emerging science of "medical geology" assesses the complex relationships between geo-environmental factors and their impacts on humans and environments and is related to the majority of the 17 Sustainable Development Goals in the 2030 Agenda of the United Nations for Sustainable Development. In this paper, we identify multiple lines of evidence for the role of GCs in the incidence of diseases with as yet unknown etiology (causation). Integrated medical geology promises a more holistic understanding of the occurrence, mobility, bioavailability, bio-accessibility, exposure and transfer mechanisms of GCs to the food-chain and humans, and the related ecotoxicological impacts and health effects. Scientific evidence based on this approach will support adaptive solutions for prevention, preparedness and response regarding human and environmental health impacts originating from exposure to GCs.
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| 65. |
- Chakraborty, M., et al.
(författare)
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Identifying the arsenic-safe aquifers of the Ganges Delta : Some insights into sustainable aquifer management
- 2018
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Ingår i: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - London : CRC Press/Balkema. - 9781138486096 ; , s. 627-628
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Konferensbidrag (refereegranskat)abstract
- The widespread health impacts on millions of people from consumption of arsenic (As) contaminated groundwater of the Ganges delta necessitate an effort to locate As-safe aquifer zones and to develop a sustainable aquifer management policy. We look into the aquifer geometries, sediment characteristics and groundwater As concentrations to develop an understanding of the factors that inhibit As invasion/mobilization within the As-safe aquifers. However, the sustainability of the present-day safe aquifer is at risk due to the heavy groundwater pumping for irrigation and thus, promoting water conserving agricultural practices is extremely vital. We suggest that, formulating a sustainable As mitigation plan should also involve the non-scientific communities such as the local tubewell drillers and farmers for widespread implementation of the plan.
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| 66. |
- Chatterjee, D., et al.
(författare)
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Arsenic in the bengal delta plain : Geochemical complications and potential mitigation option
- 2016
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Ingår i: Arsenic Research and Global Sustainability - Proceedings of the 6th International Congress on Arsenic in the Environment, AS 2016. - : CRC Press/Balkema. - 9781138029415 ; , s. 47-49
-
Konferensbidrag (refereegranskat)abstract
- Groundwaters from the Bengal Delta Plain (BDP) are now significantly enriched with natural arsenic (As), frequently exceeding the WHO guideline value (10 μg/L). The contaminated ground-water is often derived from geologically young sediments (Holocene), low-lying areas and flat terrain where groundwater movement is slow (poorly flushed aquifers). The As content of the aquifer material is not regularly high (3–18 mg/kg), however, the groundwater As content is often exceptionally high (up to 3200 μg/L). The most notable feature of the tubewell groundwater is their predominantly reducing conditions at near-neutral pH values (6.5–7.5) with high redox sensitive species. The issue of deeper aquifer (safe and unsafe) is most challenging in terms of both geological and public health point of view. In this context, deeper aquifer is possibly the most reliable source where remediation technologies are in many cases incapable of yielding As-safe water.
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| 67. |
- Chowdhury, Nilanjana Roy, et al.
(författare)
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Current opinion on the role of post-harvesting and cooking on arsenic mobility in rice grain, its surmounting risk towards human and domestic livestock with sustained management
- 2024
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Ingår i: Current Opinion in Environmental Science and Health. - : Elsevier BV. - 2468-5844. ; 38
-
Forskningsöversikt (refereegranskat)abstract
- Arsenic (As) contamination in paddy and consequently the dietary system is an emerging global threat to human health. The harvesting, post-harvesting and cooking procedures of rice in Bengal delta further involves the use of As tainted groundwater which results in a concomitant increase of As levels in sunned, parboiled, and cooked grains, respectively. Inorganic arsenic (iAs) causing potential health risks is therefore high (appx. 90 %) due to the daily rice consumption. This study sheds light on higher As accumulation, distribution and assimilation during parboiling (24 %) and cooking processes (34 %) using As-tainted water, culminating additional As burden in cooked rice. Rice grain mediated health risk has displayed a concern level of 5 according to “Severity Adjusted Margin of Exposure” value. This study also takes heed of the domestic livestock exposed to As toxicity through contaminated fodder, resulting in contaminated animal by-products which initiates further longer lasting deleterious impacts on the society.
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| 68. |
- Coomar, Poulomee, et al.
(författare)
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Contrasting controls on hydrogeochemistry of arsenic-enriched groundwater in the homologous tectonic settings of Andean and Himalayan basin aquifers, Latin America and South Asia
- 2019
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 689, s. 1370-1387
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Tidskriftsartikel (refereegranskat)abstract
- High groundwater arsenic (As) across the globe has been one of the most well researched environmental concerns during the last two decades. Consequently, a large scientific knowledge-base has been developed on As distributions from local to global scales. However, differences in bulk sediment As concentrations cannot account for the As concentration variability in groundwater. Instead, in general, only aquifers in sedimentary basins adjacent to mountain chains (orogenic foreland basins) along continental convergent tectonic margins are found to be As enriched. We illustrate this association by integrating observations from long-term studies of two of the largest orogenic systems (i.e., As sources) and the aquifers in their associated foreland basins (As sinks), which are located in opposite hemispheres and experience distinct differences in climate and land-use patterns. The Andean orogenic system of South America (AB), an active continental margin, is in principle a modern analogue of the Himalayan orogenic system associated with the Indus-Ganges-Brahmaputra river systems in South Asia (HB). In general, the differences in hydrogeochemistry between AB and HB groundwaters are conspicuous. Major-solute composition of the arid, oxic AB groundwater exhibits a mixed-ion hydrochemical facies dominated by Na-Ca-Cl-SO4-HCO3. Molar calculations and thermodynamic modeling show that although groundwater of AB is influenced by cation exchange, its hydrochemical evolution is predominated by feldspar dissolution and relationships with secondary clays. In contrast, humid, strongly reducing groundwater of HB is dominated by Ca-HCO3 facies, suggestive of calcite dissolution, along with some weathering of silicates (monosiallitization). This work demonstrates that although hydrogeochemical evolutionary trends may vary with local climate and lithology, the fundamental similarities in global tectonic settings can still lead to the elevated concentrations of groundwater As.
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| 69. |
- Datta, S., et al.
(författare)
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Understanding the relation of as and mn biogeochemistry within fe-rich sediments in southeast Asian aquifers
- 2016
-
Ingår i: Arsenic Research and Global Sustainability - Proceedings of the 6th International Congress on Arsenic in the Environment, AS 2016. - : CRC Press/Balkema. - 9781138029415 ; , s. 261-262
-
Konferensbidrag (refereegranskat)abstract
- Aquifer sediments were collected from varying depths from selected villages in Murshidabad, India. Hydrological and physico-chemical parameters of groundwater were measured and aquifer cores were collected. Solid phase analysis includes X-Ray Diffraction (XRD), X-ray Absorption Spectroscopy (XAS) and x-ray imaging. Primary focus of this work was to understand the inter-relation of As and Mn biogeochemistry in presence of Fe-rich minerals. Mechanism of As and Mn release is controlled by the oxidation-reduction of Fe bearing minerals in these subsurface aquifers. With our spectroscopy data, we have observed reduced As and Mn species in aquifer sediment as the depth increased relating directly to elevated concentration of As and Mn observed in groundwater. These observations are vital in understanding the inter-depending behavior of As and Mn in subsurface sediments.
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| 70. |
- Dhama, Kuldeep, et al.
(författare)
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SARS-CoV-2 emerging Omicron subvariants with a special focus on BF.7 and XBB.1.5 recently posing fears of rising cases amid ongoing COVID-19 pandemic
- 2022
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Ingår i: Journal of Experimental Biology and Agricultural Sciences. - : JEBAS. - 2320-8694. ; 10:6, s. 1215-1221
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Tidskriftsartikel (refereegranskat)abstract
- The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron versions have been the sole one circulating for quite some time. Subvariants BA.1, BA.2, BA.3, BA.4, and BA.5 of the Omicron emerged over time and through mutation, with BA.1 responsible for the most severe global pandemic between December 2021 and January 2022. Other Omicron subvariants such as BQ.1, BQ.1.1, BA.4.6, BF.7, BA.2.75.2, XBB.1 appeared recently and could cause a new wave of increased cases amid the ongoing COVID-19 pandemic. There is evidence that certain Omicron subvariants have increased transmissibility, extra spike mutations, and ability to overcome protective effects of COVID-19 neutralizing antibodies through immunological evasion. In recent months, the Omicron BF.7 subvariant has been in the news due to its spread in China and a small number of other countries, raising concerns about a possible rebound in COVID-19 cases. More recently, the Omicron XBB.1.5 subvariant has captured international attention due to an increase in cases in the United States. As a highly transmissible sublineage of Omicron BA.5, as well as having a shorter incubation time and the potential to reinfect or infect immune population, BF.7 has stronger infection ability. It appears that the regional immunological landscape is affected by the amount and timing of previous Omicron waves, as well as the COVID-19 vaccination coverage, which in turn determines whether the increased immune escape of BF.7 and XBB.1.5 subvariants is sufficient to drive new infection waves. Expanding our understanding of the transmission and efficacy of vaccines, immunotherapeutics, and antiviral drugs against newly emerging Omicron subvariants and lineages, as well as bolstering genomic facilities for tracking their spread and maintaining a constant vigilance, and shedding more light on their evolution and mutational events, would help in the development of effective mitigation strategies. Importantly, reducing the occurrence of mutations and recombination in the virus can be aided by bolstering One health approach and emphasizing its significance in combating zoonosis and reversal zoonosis linked with COVID-19. This article provides a brief overview on Omicron variant, its recently emerging lineages and subvairants with a special focus on BF.7 and XBB.1.5 as much more infectious and highly transmissible variations that may once again threaten a sharp increase in COVID-19 cases globally amid the currently ongoing pandemic, along with presenting salient mitigation measures.
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