| 1. |
- Annaduzzaman, Md., et al.
(författare)
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Tubewell platform color : A low-cost and rapid screening tool for arsenic and manganese in drinking water
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Presence of high level of geogenic arsenic (As) in groundwater is one of the major and adverse drinking water quality problem all over the world, especially in Southeast Asia, where groundwater is the prominent drinking water source. Bangladesh is already considered as one of the most As affected territories, where As contamination in the groundwater is key environmental disasters. Recently besides As, presence of high level of manganese (Mn) in drinking water has also got attention due to its neurological effect on children. It becomes very essential to formulate a reliable safe drinking water management policy to reduce the health threat caused by drinking As and Mn contained groundwater. The development of a simple low cost technique for the determination of As and Mn in drinking water wells is an important step to formulate this policy. The aim of this study was to evaluate the potentiality of tubewell platform color as low-cost, quick and convenient screening tool for As and Mn in drinking water wells (n=272) in a highly arsenic affected area on Matlab, Southeastern Bangladesh.The result shows strong correlation between the development of red color stain on tubewell platform and As enrichment in the corresponding tubewell water compared to WHO drinking water guideline (10 μg/L) as well as Bangladesh drinking water standard (BDWS) (50 μg/L), with certainty values of 98.7% and 98.3% respectively. The sensitivity and efficiency of red colored platforms to screen high As water in tubewells are 98% and 97% respectively at 10 μg/L, whereas at cut-off level of 50μg/L both sensitivity and efficiency values are 98%. This study suggests that red colored platform could be potentially used for primary identification of tubewells with elevated level of As and thus could prioritise sustainable As mitigation management in developing countries. Due to lack of tubewells with black colored platform in the study area, the use of platform color concept for screening of Mn enriched water in the wells have not been tested significantly, which requires further study.Acknowledgements: This study was carried out with support from the Liuuaeus-Palme Academic Exchange Programme supported by International Programs Office (IPK) and the KTH led joint collaborative action research project on Sustainable Arsenic Mitigation- SASMIT (Sid Contribution 750000854).
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| 2. |
- Aullón Alcaine, Anna, et al.
(författare)
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Geogenic arsenic and fluoride in shallow aquifers of northeastern La Pampa, Argentina : mobility constraints
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- High concentrations of geogenic arsenic (As) and fluoride (F-) in groundwater have been reported at elevated concentrations in different parts of the Chaco-Pampean Plain, in Argentina, where more than 2 million people may be exposed to high levels of these toxic elements through drinking water. Groundwater from the shallow aquifer is far exceeding the permissible WHO Standard limits of 10 μg/L for As and 1.5 mg/L for fluoride, as well as the Argentinean Standard limit of 50 μg/L for As. Geogenic As results due to the weathering of ash originated by volcanic eruptions from the Andean Cordillera and transported by wind and deposited along with the sediments and also as discrete layers and lenses over large geographical area containing around 90% of rhyolitic glass. Groundwater is hosted in a sandy silty interconnected system of aquifers and aquitards within the The Pampean aquifer. A total of 44 groundwater samples were collected from the shallow aquifers in NE of La Pampa province. Two rural areas covering an area of 600km2 in Quemú Quemú (QQ) and 300km2 in Intendente Alvear (IA) were investigated in the present study. Groundwater was circum-neutral to alkaline (pH 7.43-9.18), predominantly oxidizing (Eh ~0.24 V) with widely variable EC range (456-11,400 μS/cm). The major cation dissolved in groundwater was Na+, while the predominant anions were HCO3-, Cl- and SO42-, respectively. Water type in QQ was mostly Na-HCO3- while in IA, the composition differed between Na-HCO3- and Na-Cl-SO42- water types. Groundwater composition showed high degree of mineralization and high salinity evidenced by high EC. In discharge areas, high evaporation rates result in high salinity of shallow groundwater and visible salts incrustations on the surface of the lakes. Elevated concentrations of NO3- and PO43- observed in some wells indicated possible anthropogenic contamination. Total As concentration in groundwater from QQ ranged from 5.58 to 535 μg/L, where 94% of the wells exceeded the WHO standard limit for safe drinking water of 10 μg/L, and 56% of the wells exceeded the old Argentine standard limit of 50 μg/L. F- concentrations revealed heterogeneity and high concentrations in some wells (0.5-14.2 mg/L), 78% of samples in QQ study area exceeded the WHO standard limit of 1.5 mg/L. Under oxidizing conditions and neutral to alkaline pH, arsenate (AsV) species predominated, mainly in HAsO42- forms. As "hotspots" indicated locally contamination and correlated positively with F-, HCO3-, B and V and showed negative correlation with salinity, dissolved Fe, Al and Mn. The mechanisms involved in the mobilization of As in the shallow aquifers are controlled by the rise of pH, variations in Eh conditions and the presence of competitor ions (HCO3-, PO43-, Si, V oxyanions). Geochemical processes like adsorption/desorption, precipitation/dissolution and redox reactions may trigger to As mobilization in the shallow aquifers of La Pampa region.
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| 3. |
- Halder, Dipti, et al.
(författare)
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Assessment of arsenic exposure risk from drinking water and dietary component in West Bengal, India
- 2013
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Konferensbidrag (refereegranskat)abstract
- The current status of arsenic (As) exposure risk from drinking water and different dietary components in rural Bengal has been compared in the present study. This study shows that the consumption of rice is the major source of dietary intake of inorganic As among the population when they are drinking As safe water. Consumption of vegetables does not pose a significant health threat to the population independently; it nevertheless can increase the total daily intake of inorganic As (TDI-iAs). The results indicate that when people are drinking water with As concentration <10 μg L-1, in 35% of the cases the total daily intake of inorganic As (TDI-iAs) exceeds the previous provisional tolerable daily intake (PTDI) value of 2.1 μg day-1 kg-1 BW, recommended by World Health Organization (WHO). It should be mention here that the joint FAO/WHO expert committee on food additives (JECFA) has withdrawn the previous PTDI value in their 72nd meeting because PTDI value was in the lower range of bench mark dose level for 0.5% increased of lung cancer. However, Codex Committee on Contaminants in Foods (CCCF) has argued that TDI-iAs below BMDL0.5 does not indicates that there is no risk and this motivated us to compare TDI-iAs of the participants with the previous PTDI value of 2.1 μg day-1 kg-1 bw. At the As concentration level <10 μg L-1in drinking water, the consumption of rice is the major source of daily intake of inorganic As. When As concentration in drinking water exceeds 10 μg L-1, drinking water and rice consumption contributes almost equally (~40% from rice, ~50% from drinking water, and 10% from vegetables according to median DI-iAs) and TDI-iAs exceeds previous PTDI for all the participants. The relative contribution of daily intake of iAs from drinking water (DI-iAs-DW) largely predominates over daily intake of iAs from rice (DI-iAs-R) when As concentration in drinking water exceeds 50 μg L-1. This study implies that when consumption of rice contributes significantly to the TDI-iAs, supply of drinking water to the population considering national drinking water standard of India and Bangladesh as a safety measure for As might compound the As exposure largely by increasing TDI-iAs. Thus it can be concluded that any effort to mitigate the As poisoning of rural villagers in Bengal must look beyond the drinking water and consider all the routes of exposure.
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| 4. |
- 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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| 5. |
- Ramos, Oswaldo E., et al.
(författare)
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Bioaccessibility of arsenic and other selective trace elements in soils around the mining areas of Bolivian Altiplano
- 2013
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Ingår i: 12th International Conference on the Biogeochemistry of Trace Elements (ICOBTE). ; , s. Abstract 0220 - 000167-
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Konferensbidrag (refereegranskat)abstract
- The occurrence of trace elements (TEs) in the soils from sites of historic and present activities both open pit (extracted Au, Ag) and underground mines (Ag, Zn, Pb, Sn) mining in Bolivian Altiplano and their toxicity is one of the major environmental concerns. The aim of this study is to assess the levels of toxic trace elements such as As, Cd, Pb and Zn in the soil and their bioavailability in three sub-basins along selected transects. A combination of DTPA, and sequential extraction procedure was adapted for assessment the As content in different fraction in the soils. The results showed that TE´s were mobilized under low pH in upstream segment, thus could be considered an important factor controlling their chemical behavior in these soils. In the downstream segment of the three sub-basins, the TE enrichments were related to an increased proportion of clay contents through adsorption processes. The bioavailable fractions of the TE´s in soils indicated considerable variability for As (< 2%), Cd (<32%), Cu (<9%), Ni (<11%), Pb (<5%) and Zn (<10%). By using As sequential extraction procedure found that the less than 11% of the total As is easily mobilized in soils, they are associated to fraction related to nonspecifically (F1) and specifically sorbed (F2) fraction, which could predict a helpful tool for environmental risk assessment of these trace element contamination on Bolivian Altiplano. Enrichment factors (EF) in the soils were significantly high for As and Cd, moderate for Pb and Zn, and low for Cu, Fe, Mn and Ni contents of TE´s were high in all crops along the studied transects, and the distribution followed the trend Zn>Cu>Pb>As>Ni>Cd. The bio-concentration factor (BCF) for As, Pb and Zn were lower (< 0.5) in all crops which indicate a limited bioavailability of these TE´s, except Cd that showed high BCF values in the study area. The bioavailable TE’s might take up by the crops and finally threat human health as potential impacts.
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| 6. |
- Sandhi, Arifin, et al.
(författare)
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Arsenic in irrigation water : a threat for rice cultivation?
- 2013
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Konferensbidrag (refereegranskat)abstract
- Frequent cultivation of high yielding rice varieties (HYV) for increased food production are the key reasons for massive application of groundwater based irrigation in the rice fields of Bangladesh. Including the Asian continent, more than half of the world’s population chooses rice as their staple food and it is already considered as one of the major sources of inorganic arsenic (As) intake in the human body through food stuffs. The water logged rice cultivation method also has influence on As accumulation in rice grain. The study area Matlab located in southeastern Bangladesh, which is identified as a prominent As hotspot with incidences of high level of As in the groundwater. The objective of this study was to find out the influence of irrigation water quality and soil on the level of As in rice grain and more specifically identify the influence of iron (Fe), silicon (Si) and phosphorus (P) in the soil on the As uptake in the rice grain. A number of previous laboratory based studies has found, all three elements exert significant control on the biogeochemical interactions of As in soils and uptake in the plants.The aim of this study was to compare the level of As in rice grain and bran of different HYVs and local rice varieties, grown in this region and to compare the results with the levels of Fe, Si and P in the irrigated soils. The ICP-OES based analysis showed that the total As concentration (5.74-16.78 mg Askg-1) in the soil samples from the rice fields of the area (n=9) has exceeded the average global As concentration in the crust and soils. The concentration of Fe and Si in the soil was positively correlated with total As in the soil. The As analogue, P was positively correlated with As (R2=0.52) in the soil samples. The arsenic concentration in the irrigation water of that particular area was (> 200 μg As l -1) The AAS based analysis found that the total arsenic concentration ranged (0.017- 0.23 mg As kg-1) in the grain whereas [Asbran] was higher compared with the grains. High level of Fe present in the soil could play a significant role on the bioavailability of As due to its sorption onto the surface of the Fe-oxide colloids and roots of the rice plants. To address the As bioavailability in the rice grain, the level of As influencing elements in both grain and bran should be focused in further investigation.
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