61 research outputs found
Arsenic toxicity in Bangladesh : health and social hazards
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The "Poisoned" Body: An Anthropological study of Arsenicosis in Rural Bangladesh
Ph.DDOCTOR OF PHILOSOPH
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A Cluster-Based Randomized Controlled Trial Promoting Community Participation in Arsenic Mitigation Efforts in Bangladesh
Millions of villagers in Bangladesh drink water which exceeds the Bangladesh arsenic (As) standard of 50 micrograms per liter. Exposure to elevated levels of inorganic As (As) is associated with cancers of the skin, bladder, and lung, developmental effects, cardiovascular disease, skin lesions, and decreased children's intellectual functioning. Arsenic mitigation typically involves an outsider coming into a village to test the well water for As. After the results of the As test are provided this person typically leaves the village without providing the resources to address health concerns or give advice on mitigation options. In this dissertation, in an effort to provide ongoing resources on the health implications of As and to reduce As exposure, we sought to evaluate community level intervention strategies that could be used for successful As mitigation in Bangladesh. In Singair, Bangladesh, we conducted a household drinking water survey of 6649 households. The results of our survey indicated that 80% of wells were untested for As. Furthermore, we demonstrated that testing all of these untested wells would increase the number of households that lived with fifty meters of an As safe drinking water source by nearly 2.5 fold. In a cluster based randomized control trial (RCT) of 1000 households, we evaluated the effectiveness of having community members, compared to outside representatives, disseminate As education and conduct water As (WAs) testing. In 10 villages, a community member disseminated As education and provided WAs testing. In a second set of 10 villages an outside representative performed these tasks. Overall, fifty three percent of respondents with unsafe wells at baseline switched after receiving the As education and WAs testing intervention. There was no significant association observed between the type of As tester and well switching (Odds ratio (OR) =0.77; 95% confidence interval (CI) (0.37-1.61)). At follow-up, the average UAs concentrations for those with unsafe wells at baseline who switched to safe wells significantly decreased. In both intervention groups a significant increase in knowledge of As was observed at follow-up compared to baseline. The unavailability of As-safe drinking water sources in some villages was the most substantial barrier to well switching identified. The Hach EZ As field test kit measurements conducted by the As testers were highly correlated with laboratory results. This finding indicates that the As testers were able to accurately measure the WAs concentration of wells. Furthermore in our pilot study, the performance of the Econo-Quick (EC) kit, a new field WAs testing kit, was comparable to that of the commonly used EZ kit and the Wagtech Arsenator kit. The EC kit has the advantage of a substantially shorter reaction time of only 12 minutes in comparison to the 40 minutes required by these other kits. Through this dissertation, we have demonstrated that As education and WAs testing programs can be used as an effective method to reduce As exposure and increase As awareness in many As affected areas of Bangladesh. Furthermore, our findings indicated that many households are using tubewells that are untested for As therefore demonstrating the urgent need for access to water As testing services
Arsenic mobilization processes in the red river delta, Vietnam : towards a better understanding of the patchy distribution of dissolved arsenic in alluvial deposits
The spatial variability of dissolved arsenic (As) concentrations in aquifers was studied near Ha Noi, Vietnam. The goal was to identify major geochemical, sedimentological and hydrochemical differences between high and low As regions. Also, the behaviour of As and other elements during sequential extractions was characterized with micro synchrotron XRF analysis. Based on the results a conceptual model was developed which could explain the current situation on site and in other affected areas
A baseline appraisal of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change
This report forms part of a larger research programme on 'Reinterpreting the Urban-Rural Continuum', which conceptualises and investigates current knowledge and research gaps concerning 'the role that ecosystems services play in the livelihoods of the poor in regions undergoing rapid change'. The report aims to conduct a baseline appraisal of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change. The appraisal is conducted at three spatial scales: global, regional (four consortia areas), and meso scale (case studies within the four regions). At all three scales of analysis water resources form the interweaving theme because water provides a vital provisioning service for people, supports all other ecosystem processes and because water resources are forecast to be severely affected under climate change scenarios. This report, combined with an Endnote library of over 1100 scientific papers, provides an annotated bibliography of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change.
After an introductory, section, Section 2 of the report defines water-related ecosystem services and how these are affected by human activities. Current knowledge and research gaps are then explored in relation to global scale climate and related hydrological changes (e.g. floods, droughts, flow regimes) (section 3). The report then discusses the impacts of climate changes on the ESPA regions, emphasising potential responses of biomes to the combined effects of climate change and human activities (particularly land use and management), and how these effects coupled with water store and flow regime manipulation by humans may affect the functioning of catchments and their ecosystem services (section 4). Finally, at the meso-scale, case studies are presented from within the ESPA regions to illustrate the close coupling of human activities and catchment performance in the context of environmental change (section 5). At the end of each section, research needs are identified and justified. These research needs are then amalgamated in section 6
Safe Drinking Water Policy for Canada - Turning Hindsight into Foresight
Much of Canada lags international leaders in adopting management systems for assuring safe drinking water. Despite some clear progress in individual provinces, Canada, and small communities in particular, need a system that better promotes and rewards competence among drinking water providers. In much of the developed, industrialized world, including most of urbanized Canada, public drinking water poses a negligible health risk. But in the wake of a series of management failures with severe negative health consequences, Canada’s drinking water regulation is still managed in a fragmented way that leaves us vulnerable to water-quality failures, most likely in small systems. The problem is not that numerical water safety criteria are inadequately stringent; the documented failures have been caused by an inability to operate water systems effectively, pointing to poor operator competence and inadequate support systems. Canada needs the universal adoption of a “know your own system” water safety plan approach, based on a tangible demonstration of operator competence in understanding and delivering safe drinking water.Water Series, Canada, safe drinking water
Groundwater research and management: integrating science into management decisions. Proceedings of IWMI-ITP-NIH International Workshop on "Creating Synergy Between Groundwater Research and Management in South and Southeast Asia," Roorkee, India, 8-9 February 2005
Groundwater management / Governance / Groundwater development / Artificial recharge / Water quality / Aquifers / Groundwater irrigation / Water balance / Simulation models / Watershed management / Water harvesting / Decision making / South East Asia / Bangladesh / China / India / Nepal / Pakistan / Syria
Impact of Water Components on Iron Nail Corrosion and Arsenic Removal Efficiency of The Kanchan Arsenic Filter (KAF)
The Kanchan Arsenic Filter (KAF) is an intermittent, point-of-use, affordable drinking water technology for the removal arsenic from groundwater. Performance of KAFs in Nepal has been variable, with high removal in some settings and low removal in others. This study consisting of two parts (laboratory and field research) was conducted to improve the perfomance of the KAFs.In the laboratory research, four different synthetic groundwaters spiked with arsenic were fed to the filters once a day for 35 days to evaluate the effect of water components on corrosion of iron nails and of arsenic removal in downscaled KAFs. Composition of water samples collected from those filters was analyzed using UV-Vis spectroscopy, Flame - atomic absorption spectrophotometry (F-AAS), and inductively coupled plasma mass spectrometry (ICP-MS). Morphology of iron nail surface was done by scanning electron microscopy – energy dispersive spectroscopy (SEM-EDS), followed by a characterization of iron rust powder using X-ray powder diffraction (XRD). Colloids of iron corrosion products were analyzed using transmission electron microscopy (TEM) for their phase, images and structure. Batch tests were conducted to examine iron corrosion rates of iron nails in the presence of 2,2-bipyridine under different testing conditions. The field research in Nepal containing water quality assessments, filter checks, and household interviews was carried out to explore potential factors causing a bias and inadequate filter performance.
Results from the lab research showed remarkable impacts of water conditions on iron corrosion and arsenic removal by the KAFs, with the strong enhancing effect of hardness surpassing the inhibiting effect of phosphate. Filters running hardness-rich water (200 mg/L Ca) removed arsenic (initial concentration of 2000 µg/L) to under the limit of Nepali water standard (50 µg/L) while filters running low hardness water (40 mg/L Ca) removed much less arsenic, especially in the presence of phosphate. On average, 35.7 to 47.9% of arsenic was removed after contacting with iron nails while total arsenic removal was 85.2 to 99.5% over the duration of this study.
The field research revealed that inconsistencies in performance of the full-scale KAFs were mostly resulting from variations of groundwater quality, improper methods of maintenance and operation of the filter users and unfavorable water conditions. A change in nail type showed a moderate difference on filter performance. Addition of embedded nails in filter media significantly facilitated arsenic removal and is a promising solution for enhancing the KAF performance
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