| 1. |
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| 2. |
- Hossain, M., et al.
(författare)
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Potentiality of intermediate depth aquifer as a source of arsenic and manganese safe tubewells in Bangladesh
- 2012
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Ingår i: Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment. - : Taylor & Francis Group. - 9780415637633 ; , s. 71-73
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Konferensbidrag (refereegranskat)abstract
- Shallow tubewells excepting those installed in red/off-white sediments are mostly contaminated with high arsenic. Social survey conducted in 96 villages of Matlab, a worse-affected area of Bangladesh, reveals that only 18% of tubewells provide As-safe water. In such a condition, high Manganese in many wells is found to be an additional problem. Based on monitoring in depth-specific piezometers, drinking water wells were installed in intermediate depth aquifer around 120 m. Ninety percent of the wells installed in light grey medium sand, had arsenic concentrations below the Bangladesh standard of 50 ÎŒg/L and manganese was within the previous WHO guideline (0.4 mg/L). Availability of similar sand over this depth range could be targeted by local drillers to tap safe water at a reasonable cost. Replication trials and periodical monitoring are emphasized for validation and sustainability.
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| 3. |
- Hossain, Mohammad, et al.
(författare)
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Strategic approach for up-scaling safe water access considering hydrogeological suitability and social mapping in Matlab, southeastern Bangladesh
- 2013
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Konferensbidrag (refereegranskat)abstract
- In recent years, there has been a significant progress in understanding the source and mobilization process, sediment-water interactions, and distributions of arsenic in groundwater environment in Bangladesh. However, the impacts of arsenic mitigation are still very limited. A social survey conducted during 2009-2011 in 96 villages in Matlab revealed that only 18% of total tubewells provide As-safe water. The safe water access also varied between 0 and 90 percent in the region due to lack of knowledge about the local geology and unplanned tubewell development. SASMIT, an initiative of KTH-International Groundwater Arsenic Research Group has developed a method for safe tubewell installation considering hydrogeological suitability, safe water access and other relevant social and demographic information into account.Piezometers installed at 15 locations over an area of 410 km2, using local boring techniques allowed to delineate the hydrostratigraphy, characterize the aquifers in terms of sediment characteristics, water chemistry and hydraulic head distribution, which ultimately led to the identification of the suitable aquifers for tapping safe water. The piezometer locations with safe drinking water quality were then targeted for safe well installation based on the determination of safe buffer distances in a cluster of a few villages (mouzas). Social mapping of all the villages within the mauzas were done using GIS to evaluate the availability of safe water options for a cluster of households (bari). For safe well installations, priority was given to regions with safe water access, greater number of beneficiaries especially in poor households, and easy access to the site from a cluster of households. Through this approach, it was thus possible to make 95% of the newly installed wells As-safe thus scaled up the safe water access upto 40% in some mauzas. Thus the as a strategy to improve safe water access, the SASMIT study recommends investigating the hydrogeological suitability through installation of few piezometers with a minimum effort and based on the results the implementation plan can be made using GIS based social mappings for relatively uniform distribution and to maximize the safe water access.
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| 4. |
- Jacks, B., et al.
(författare)
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The influence of fodder on vitamin A and ?-carotene in milk - Sahelian mali
- 1999
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Ingår i: Ecology of Food and Nutrition. - 0367-0244 .- 1543-5237. ; 38:2, s. 145-164
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Tidskriftsartikel (refereegranskat)abstract
- Vitamin A deficiency has been reported on repeatedly in recent years from the Sahel region in West Africa. Nomadism, pastoralism and agro-pastoralism are the common systems for food production in the area. Milk was a major food item prior to the repeated droughts of the past few decades. This investigation has looked at the retinol content in milk from various domestic animals at the end of the dry season, which is critical from vitamin A supply point of view. Milk from cows fed on hay from the previous year was devoid of retinol, while milk from goats contained good levels regardless of whether the source of fodder was browse or fresh grass after the onset of rains. Acacia tortilis, a common and preferred fodder tree, is rich in ?-carotene. Establishing small-scale cultivation of other ?-carotene rich, indigenous, woody, non-spiny fodder-species such as Maerua crassifolia, is therefore proposed to increase the vitamin A content, and therefore the value of cow's milk. This could be integrated into the ongoing tree-plantation programs for dune stabilisation.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Bhattacharya, Prosun, et al.
(författare)
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Geogenic arsenic in groundwaters from Terai Alluvial Plain of Nepal
- 2003
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Ingår i: Journal de Physique IV. - : EDP Sciences. - 1155-4339 .- 1764-7177. ; 107, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- The origin and mobility of arsenic (As) in the groundwater environment has received serious attention in recent years. Recent studies have reported naturally occurring As in groundwaters of the Terai Alluvial Plains (TAP) in southern Nepal, where groundwater exploitation has increased since the 1960s. The source of As in TAP is geogenic and leached primarily due to weathering of As bearing rocks and sediments in the Himalayas. In our present study, we have investigated the groundwater chemistry in the central part of the TAP in Nawalparasi district. TAP groundwaters are near-neutral to alkaline, with predominantly reducing character and high HCO3-, low SO4- and NO3- concentrations. Elevated HCO3 levels possibly result due to the oxidation of organic matter, low SO42- levels reflect sulfate reduction. Elevated NH4+ concentrations in these groundwaters suggest dissimilatory nitrate reduction in the aquifers. Total arsenic (As,.,) levels in groundwater varied from 1.7 mug/L to as high as 404 mug/L with dominance of As(III) species and elevated levels of dissolved Fe and Mn. Arsenic is mobilized in groundwaters as a result of desorption of As-oxyanions adsorbed onto Fe- and Mn-oxides as well as reductive dissolution of these surface reactive phases from the sediments along with release of As in anoxic groundwaters.
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| 9. |
- Bhattacharya, Prosun, et al.
(författare)
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Metal contamination at a wood preservation site : characterisation and experimental studies on remediation
- 2002
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Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 290:03-jan, s. 165-180
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this investigation was to determine the occurrence of As, Cu, Cr and Zn in the soil at an abandoned wood preservation unit and to examine some possible extractants for the contaminants in the soil. The mean As content of the contaminated surface soils (0-10 cm) was 186 mg kg(-1), where as the mean concentrations of Cu, Cr and Zn in soils from the contaminated area were 26, 29 and 91 mg kg(-1), respectively. The elevated As content in the mineral soils is related to adsorption of inorganic As phases in the fine grained fractions, which are characterised by large surface area and high positive surface charge under the current acidic conditions. Cu and Cr were found to be rather mobile, which is reflected in their lower abundance in soils and significant accumulation in sediments in the drainage leaving the area. The fine fraction of the soil (<0.125 mm) has an average metal content increased by nearly 34% as compared to the <2-mm fraction conventionally used for the analysis and assessment of soil contamination. The <2-mm fraction constitutes approximately 65% of the total weight while the fine fraction (< 0.125 mm) constitutes approximately 10%. These facts, taken together, are essential for the choice of remediation measures. Oxalate solutions have been tested as extractants for soil remediation. Dark acid oxalate extraction dissolves the amorphous Al- and Fe-oxides and hydroxides and mobilises the adsorbed inorganic As species. Oxalate also acts as a ligand for the cationic heavy metals, releasing them from exchangeable sites. With a three-step sequential leaching, up to 98-99% of the metals could be removed. At lower concentrations and higher pH, the leaching decreased to approximately 70%.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Hossain, Mohammed, 1960-, et al.
(författare)
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Sustainable Arsenic Mitigation (SASMIT) : An approach for developing a color based tool for targeting arsenic-safe aquifers for drinking water supply
- 2012
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Ingår i: METALS AND RELATED SUBSTANCES IN DRINKING WATER. - : IWA PUBLISHING. ; , s. 272-276
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Konferensbidrag (refereegranskat)abstract
- Presence of high concentration of geogenic arsenic (As) in water and soil become a big health risk towards millions of people in various magnitudes through drinking water. To minimize arsenic interaction with human considered as a global challenge. The main objective of this research is to develop a simple, easy and cost-effective arsenic identification tool which would be easily acceptable by the inhabitants and local well drillers. The relationship of sediment color and corresponding As concentrations in water has already been demonstrated and is being further studied under SASMIT project. A total of 1920 sediment samples from 15 locations bored up to a depth of 250 m have been scientifically evaluated according to the color codes using Munsell Color Chart. A total of 60 varieties observed and simplified into four color groups viz. black, white, off-white and red. It is revealed that red and off-white sands can be targeted for As-safe water. White sands can also be safe but uncertainty is high and black sediments produce water with highest As concentration, although Mn content in waters sampled from white and black sediments is relatively low. Further refinement is going on for improving the tool for targeting aquifers which can be safe for both arsenic and manganese.
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| 14. |
- Jacks, G., et al.
(författare)
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Arsenic and trace metal mobility in alum shale areas in Sweden
- 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. 196-197
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Konferensbidrag (refereegranskat)abstract
- Alum shales found in Sweden are enriched in As and trace metals like Mo, Zn, Cd, Ni and U with the redox conditions being crucial for the mobilization of those elements. The shales have been mined, e.g. for uranium. Uranium is mobilized under oxidizing conditions, while arsenic is mobilized under reducing conditions. This plays a role under natural conditions in the alum shale but more so in the tailings after mining. An investigation of a natural area indicates small environmental risks while the utilization of the shales has left tailings that tend to leak into the environment.
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| 15. |
- Jacks, G., et al.
(författare)
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Controls on the genesis of some high-fluoride groundwaters in India
- 2005
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Ingår i: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 20:2, s. 221-228
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Tidskriftsartikel (refereegranskat)abstract
- India has an increasing incidence of fluorosis, dental and skeletal, with some 62 million people at risk. High fluoride groundwaters are present especially in the hard rock areas south of the Ganges valley and in the and north-western part of the country. The phenomenon is related to groundwater with residual alkalinity (Ca2+ < HCO3-). Fluoride concentrations are governed by adsorption equilibria and by fluorite solubility. Evapotranspiration leads to a precipitation of calcite, a lowering of Ca activity and increase in Na/Ca ratios, and this allows an increase in F- levels. In southern India, Mg seems to be controlled by dolomite, while sepiolite and palygorskite are Mg sinks in Rajasthan but may then release F- under alkaline conditions. The latter two minerals are probably also important sources and sinks for F- in the hydroxy-positions. The increase in the extent of sodic soils as a result of irrigation is a contributing factor to the increasing incidence of fluorosis. Remedial measures including addition of gypsum and rainwater harvesting are needed even in areas where the sodicity does not cause structural problems in the soil.
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| 16. |
- Jacks, G., et al.
(författare)
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Fluoride mobilisation in India
- 2009
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Ingår i: Geochimica et Cosmochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0016-7037 .- 1872-9533. ; 73:13, s. A578-A578
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 17. |
- Jacks, G., et al.
(författare)
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Tentative nitrogen budget for pit latrines - Eastern Botswana
- 1999
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Ingår i: Environmental Geology. - : Springer Science and Business Media LLC. - 0943-0105 .- 1432-0495. ; 38:3, s. 199-203
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Tidskriftsartikel (refereegranskat)abstract
- A major problem with on-site sanitation is nitrate pollution of the groundwater. A tentative nitrogen budget is established for pit latrines in eastern Botswana. The ammonia volatilisation was found to be negligible while leaching varied largely from about 1 to 50%. Leaching of nitrate was assessed by using chloride as tracer, assuming two sources of chloride, atmospheric deposition and the use of common salt in food. The initial content of nitrogen in excreta was assessed from nutritional data. The residual nitrogen in abandoned latrines as found by analysis, was 15–20%. The remainder should be denitrification which would then be in the order of 30–70%. That denitrification is important is supported by an elevated N-isotope ratio in groundwater and in deep-rooted non-N-fixing trees. The varying leaching rate provides a possibility of checking it by sealing the latrines. Since about 95% of the nitrogen in human excreta is present in the urine, an even more attractive solution would be urine-separating latrines with surface near percolation of the urine in the root zone of the vegetation, utilising it for crop growth. Since such latrines are used elsewhere in the world the problem is not technical but social acceptability.
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| 18. |
- Kibria, M. G., et al.
(författare)
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Hydrogeochemistry and microbial geochemistry on different depth aquifer sediments from Matlab, Bangladesh
- 2014
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Ingår i: One Century of the Discovery of Arsenicosis in Latin America (1914-2014). - : CRC Press. - 9781138001411 ; , s. 101-103
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Konferensbidrag (refereegranskat)abstract
- Arsenic (As) poses the greatest hazard towards drinking water quality in Bangladesh. Tubewell drinking water is one of the main sources for household based water options in rural Bangladesh. Our study area is in Matlab Upazila, in Bangladesh. The overall objective of this research and the SASMIT project is to develop a community based initiative for sustainable As mitigation by developing a sediment color based tool for the local drillers prioritizing on the hydrogeological and biogeochemical investigations. For this purpose we analyzed different depth colored sediments and water for find out the sustainable low Arsenic contaminated aquifer.
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| 19. |
- Lau, Allison N., et al.
(författare)
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Dissecting cell-type-specific metabolism in pancreatic ductal adenocarcinoma
- 2020
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Ingår i: eLife. - 2050-084X. ; 9, s. 1-35
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Tidskriftsartikel (refereegranskat)abstract
- Tumors are composed of many different cell types including cancer cells, fibroblasts, and immune cells. Dissecting functional metabolic differences between cell types within a mixed population can be challenging due to the rapid turnover of metabolites relative to the time needed to isolate cells. To overcome this challenge, we traced isotope-labeled nutrients into macromolecules that turn over more slowly than metabolites. This approach was used to assess differences between cancer cell and fibroblast metabolism in murine pancreatic cancer organoid-fibroblast co-cultures and tumors. Pancreatic cancer cells exhibited increased pyruvate carboxylation relative to fibroblasts, and this flux depended on both pyruvate carboxylase and malic enzyme 1 activity. Consequently, expression of both enzymes in cancer cells was necessary for organoid and tumor growth, demonstrating that dissecting the metabolism of specific cell populations within heterogeneous systems can identify dependencies that may not be evident from studying isolated cells in culture or bulk tissue.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Shams, S, et al.
(författare)
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Mapping and interpretation of field data for evaluation and mitigation of groundwater arsenic contamination in Bangladesh
- 2006
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Ingår i: Journal of Hydroinformatics. - : IWA Publishing. - 1464-7141 .- 1465-1734. ; 8:1, s. 25-36
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Tidskriftsartikel (refereegranskat)abstract
- Problems of arsenic contamination have been reported from a large number of aquifers in various parts of the world. Especially in Bangladesh, the presence of arsenic in groundwater has been the major environmental health catastrophe that has affected the source of safe water not only for drinking but also for irrigation purposes. The unavailability and inaccessibility of data and dissemination of proper and rapid information has further reduced the accessibility to safe drinking water for nearly 95% of the population of the country. The development of solutions for the arsenic problem and the allocation of resources for mitigation are information-oriented activities. This paper focuses on the mapping and interpretation of field data (based on a case study area) through the application of GIS for presenting and assessing the scope of the arsenic problem in Bangladesh. The mapping and interpretation is done taking into consideration the geophysical characteristics, socio-economic conditions and socio-cultural behavior of the people living in the study area. The mapping and interpretation technique is aimed at assisting lanners and policy makers at the district level to make an assessment about the extent and magnitude of the arsenic problem based on an estimation of the exposed population and the extent and severity of groundwater contamination. In addition, it will enable decision-makers to select possible options and give recommendations based on users’ responses. The advantages of this interpretation technique are that the knowledge base is easy to build and any updated information or modifications can be quickly incorporated into the knowledge base.
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