| 1. |
- Bhowmick, S., et al.
(författare)
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Arsenic mobilization in the aquifers of three physiographic settings of West Bengal, India : Understanding geogenic and anthropogenic influences
- 2013
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 262, s. 915-923
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Tidskriftsartikel (refereegranskat)abstract
- A comparative hydrogeochemical study was carried out in West Bengal, India covering three physiographic regions, Debagram and Chakdaha located in the Bhagirathi-Hooghly alluvial plain and Baruipur in the delta front, to demonstrate the control of geogenic and anthropogenic influences on groundwater arsenic (As) mobilization. Groundwater samples (n=90) from tube wells were analyzed for different physico-chemical parameters. The low redox potential (Eh=-185 to -86mV) and dominant As(III) and Fe(II) concentrations are indicative of anoxic nature of the aquifer. The shallow (<100m) and deeper (>100m) aquifers of Bhagirathi-Hooghly alluvial plains as well as shallow aquifers of delta front are characterized by Ca2+HCO3 - type water, whereas Na+ and Cl- enrichment is found in the deeper aquifer of delta front. The equilibrium of groundwater with respect to carbonate minerals and their precipitation/dissolution seems to be controlling the overall groundwater chemistry. The low SO4 2- and high DOC, PO4 3- and HCO3 - concentrations in groundwater signify ongoing microbial mediated redox processes favoring As mobilization in the aquifer. The As release is influenced by both geogenic (i.e. geomorphology) and anthropogenic (i.e. unsewered sanitation) processes. Multiple geochemical processes, e.g., Fe-oxyhydroxides reduction and carbonate dissolution, are responsible for high As occurrence in groundwaters.
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| 2. |
- Halder, Dipti, et al.
(författare)
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Risk of arsenic exposure from drinking water and dietary components : Implications for risk management in rural Bengal
- 2013
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:2, s. 1120-1127
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the risk of arsenic (As) exposure to the communities in rural Bengal, even when they have been supplied with As safe drinking water. The estimates of exposure via dietary and drinking water routes show that, when people are consuming water with an As concentration of less than 10 μg L-1, 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 the World Health Organization (WHO) in 35% of the cases due to consumption of rice. When the level of As concentration in drinking water is above 10 μg L-1, the TDI-iAs exceeds the previous PTDI for all the participants. These results imply that, when rice consumption is a significant contributor to the TDI-iAs, supplying water with an As concentration at the current national drinking water standard for India and Bangladesh would place many people above the safety threshold of PTDI. We also found that the consumption of vegetables in rural Bengal does not pose a significant health threat to the population independently. This study suggests that any effort to mitigate the As exposure of the villagers in Bengal must consider the risk of As exposure from rice consumption together with drinking water.
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| 3. |
- Annaduzzaman, Md, et al.
(författare)
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Arsenic and manganese in shallow tubewells : validation of platform color as a screening tool in Bangladesh
- 2018
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Ingår i: Groundwater for Sustainable Development. - : Elsevier B.V.. - 2352-801X. ; 6, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to evaluate the potential of handpump tubewell platform color as a low-cost, quick and convenient screening tool for As and Mn in drinking water tubewells. For this study, groundwater samples and corresponding tubewell platform pictures were collected from 272 shallow tubewells in Matlab Upazila of South-Eastern Bangladesh. The result shows that arsenic concentration within the surveyed (n = 272) tubewells, 99% (n = 269) exceeded the World Health Organization (WHO) guideline value of 10 µg/L, and 98% (n = 267) exceeded the Bangladesh drinking water standards (BDWS) of 50 µg/L. In relation to the platform color concept, within 233 (total 272) red colored platform tubewells, 230 (99%) exceeded the WHO guideline value of 10 µg/L, and 229 (98%) tubewells exceeded BDWS of 50 µg/L. This result shows a strong correlation between the development of red color stain on tubewell platform and As concentrations in the corresponding tubewell water. This study suggests that red-colored platform can be used for primary identification of tubewells with an elevated level of As and thus could prioritize sustainable As mitigation management in developing countries where water comes from reductive shallow aquifers. This study did not confirm the potential for Mn screening, as red discoloration by Fe oxides was found to mask the black discoloration of Mn oxides. It is recommended to further investigate this screening tool in regions with a higher well-to-well variability of As contaminations, as in the presented study As was found >10ug/L in 99% of the tubewells.
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| 4. |
- Bhattacharya, Prosun, 1962-, et al.
(författare)
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Tubewell platform color : Assessment of a tool for rapid screening of arsenic and manganese in well water
- 2012
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Ingår i: UNDERSTANDING THE GEOLOGICAL AND MEDICAL INTERFACE OF ARSENIC, AS 2012. - : CRC PRESS-TAYLOR & FRANCIS GROUP. ; , s. 515-518
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Konferensbidrag (refereegranskat)abstract
- This study attempts to make a statistical comparison between Tubewell (TW) platform color and the level of Arsenic (As) and Manganese (Mn) concentration in groundwater abstracted from a set of 423 Tubewells (TWs) in Chakdaha Block of Nadia District, West Bengal, India to validate platform color as a screening tool for both As and Mn in groundwater. The results indicate that water extracted from TWs with black colored platform in 93% cases was safe for As while water extracted from TWs with red colored platform is contaminated with As with 38% certainty, compared to drinking water standard of India (50 mu g/L). At this standard the respective efficiency, sensitivity and specificity of the tool are 65, 85 and 59%. If WHO drinking water guideline (10 mu g/L) is considered, the certainty increases to 73% and 84% respectively for black and red colored platform with respective efficiency, sensitivity and specificity values of 79, 77 and 81%. Furthermore, the black colored platform with 78% certainty indicates well water is enriched with Manganese (Mn), while red colored platform indicates water is low in Mn with 64% certainty evaluated against Indian national standard of 300 mu g/L. This study demonstrates that platform color can be potentially used as an initial screening tool for As and Mn, to assess the safe water acess for drinking purposes.
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| 5. |
- Biswas, Ashis, et al.
(författare)
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Potentiality of shallow brown sand aquifers as an alternative safe drinking water source in Bengal Basin
- 2012
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Ingår i: Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment. - 9780415637633 ; , s. 67-68
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Konferensbidrag (refereegranskat)abstract
- The present study investigated the regional distribution of brown sand aquifers (BSA) as well as their hydrogeochemical contrast to grey sand aquifers (GSA). The data indicated that in BSA redox status is limited to the Mn oxides reduction stage, while in GSA, Fe oxides reduction to SO 4 2- reduction processes are prevalent. Though, the concentration of dissolved As was very low (<10 ÎŒg/L) in BSA, the concentration of Mn was very high (>400 ÎŒg/L). Whereas in GSA, the enrichment patterns of As and Mn were opposite to that of BSA. This study suggests that underlying health risk of Mn in drinking water needs to be addressed more rigorously before advocating for mass scale exploitation of BSA as an alternative drinking water source despite of significantly low As concentration in groundwater.
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| 6. |
- Halder, Dipti, et al.
(författare)
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Arsenic exposure and health risk from consumption of brown rice in rural Bengal, India
- 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. 505-507
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Konferensbidrag (refereegranskat)abstract
- This study investigates the Arsenic (As) concentration in different types of brown rice grain and assesses As exposure and non-cancer health risk from rice consumption. Daily Intake (DI rice) and Hazard Quotient (HQ) from rice were calculated for the people who are consuming these type of rice. Daily intake value of As from rice was compared with previous WHO recommended Provisional Tolerable Daily Intake value (PTDI) of 2.1 ÎŒg/day/kg bw to understand which kind of rice may pose potential health risk. Hazard quotient (HQ) was determined to understand the potential non-cancer health risk of the people who are consuming these rice. This study indicates that for SB brown rice consumer in 29% cases DI rice exceeds the previous PTDI value and 100% cases HQ value exceeds 1.
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| 7. |
- 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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