Widespread Arsenic Contamination Research Articles

Effect of Arsenic on Health: Evidence from Indian Districts

It is well established that consuming groundwater contaminated with arsenic can lead to diseases of the heart, blood vessels, peripheral nervous systems and skin diseases such as pigmentation change. In this article, I focus on two health outcomes—skin diseases and still births—using district-level data from India, a country with widespread arsenic contamination. Arsenic may come into human contact via direct and/or indirect channel. I intend to examine these two channels of arsenic transmission. To analyse the two-fold objectives of this study, I have used repeated cross-section data from the two health rounds of National Sample Survey Organization (60th and 71st round survey). I find a positive and statistically significant relation between skin diseases and drinking water from arsenic contaminated tube well. Similar results are found for still birth in arsenic affected areas, even after controlling for state- and district-level factors. Using odds ratio, I also find positive effect of rice consumption on skin manifestations, robust to state-fixed effects, but not district-fixed effects. Individuals are more adversely affected in terms of skin lesions and adverse pregnancy outcomes. Drinking arsenic contaminated water is a more dominant pathway than consumption of food containing arsenic, particularly rice and wheat. JEL Codes: I10, I12, Q25, Q53, Q54

Arsenic contamination in food chain - a menace to food safety, human nutrition and health

The metalloid arsenic is one of the persistent toxic elements that has affected a vast population of human being across the globe. Its lethal and unsafe levels in drinking water have been witnessed by more than 100 million people in the South and South-east Asia alone. Literatures suggest that contaminated groundwater is the potential source for arsenicosis. Widespread arsenic contamination in surface water, soil and sediments-either of geogenic or anthropogenic origin-has resulted in presence of this carcinogenic pollutant in plant and animal produce such as rice, vegetables, milk, meat, fish, etc. Further, the arsenic mediated stress to all living organisms is of great concern. Thus, the entire biome is under massive threat of arsenic. The extent and severity of arsenic contamination in human diet has challenged the safety aspect of human nutrition and health. The chronic arsenicism in human is of greater concern and demands immediate implementation of mitigative measures. The risk of arsenic toxicity through water as well as food and possible way-out have been discussed in this review.

Analysis of spatio-temporal trend in groundwater elevation data from arsenic affected alluvial aquifers – Case study from Murshidabad district, West Bengal, Eastern India

Fluctuation in groundwater level is a time-dependent stochastic process. It is also a function of various inflow and outflow components to and from the hydrologic system concerned. Depth to water level data are measured through a network of observation wells or hydrograph stations to ascertain the degree of fluctuation in groundwater level at the desired scale, on a long-term basis. Basically, these depths to water level data are point measurements, which can be regarded as random variables furnishing changes in groundwater storage over time. The intrinsic in-homogeneity in aquifer materials introduces variations like jumps, trends, and periodicities in such hydrologic time series data. Thus, trending results from certain gradual, natural and/or anthropogenic interventions in the hydrologic environment and analyses of their trends are imperative for assessment of groundwater level scenario in the area of interest. This in turn, is essential for strategic planning and management for exploitation of the precious groundwater resource in the same area. The area of interest in this article, i.e., Murshidabad is one of the nine arsenic affected districts of West Bengal. Here, contamination persist within, shallow, arseniferous, alluvial aquifers, which are otherwise widely exploited for irrigation purposes. According to many researchers working in this area, over-exploitation of groundwater is the root cause for the plummeting water level and the widespread arsenic contamination as well. The present study intends to detect and analyze the trends persisting in the depth to water level data measured over a period from 1996 to 2016, in Murshidabad district of West Bengal, India, amidst its complex and contrasting hydrogeologic set-up and interpret the results in terms of the hydrologic attributes of the Bengal basin as a whole. The non-parametric Mann–Kendall test and the Sen’s slope estimator have been used to identify the linear trend persisting in the time series pre- and post-monsoon groundwater elevation values. The analysis indicates statistically significant decline in water level across the study area especially during the post-monsoon season. This can be attributed to the recharge–discharge disparity within the hydrologic regime; brought through intense pumping over the study area. Its ill effect being particularly observed in the western part of river Bhagirathi. Findings of such study are crucial for assessment of dynamic groundwater resources of the district and subsequently can be utilized as a decision support tool for groundwater management at micro-level.

Elucidating the physiological mechanisms underlying enhanced arsenic hyperaccumulation by glutathione modified superparamagnetic iron oxide nanoparticles in Isatis cappadocica

Widespread arsenic (As) contamination is a severe environmental and public health concern. Isatis cappadocica, an arsenic hyperaccumulator, holds great potential to clean up As-contaminated soil and groundwater. Iron oxide is one of the most common metal oxides in the natural environment and its nanoparticulate form has been previously utilized for the removal of heavy metals/metalloids from wastewater. However, there is a paucity of information on the impact of iron oxide nanoparticles on the growth and physiological properties of I. cappadocica and its effectiveness on As removal. Current study reports for the first time the impact of superparamagnetic iron oxide nanoparticles and glutathione (GSH) modified superparamagnetic iron oxide nanoparticles (nFe3O4 and nFe3O4@GSH) on the physiological characteristic of I. cappadocica and its accumulation of As under hydroponic condition. nFe3O4@GSH alleviated the harmful impact of As and significantly increased the shoot biomass of I. cappadocica by enhancing the plant defense mechanisms. The application of GSH, nFe3O4 and nFe3O4@GSH all lowered the As concentration in plant shoots as a protective mechanism. However, the substantial shoot biomass increase due to nFe3O4@GSH resulted in a 56% higher As accumulation in plant shoots than in plants exposed to As alone, indicating the strong effectiveness of nFe3O4@GSH as a novel enhancer of the As phytoremediation by I. cappadocica. Our data further showed that the beneficial effect of nFe3O4@GSH on As phytoremediation is due to the enhancement of activities of several enzymatic and nonenzymatic antioxidants.

Exposure amount / duration leading to carcinogenesis due to chronic arsenic exposure–Examination of carcinogenesis avoidance by exposure reduction

Around the world thousands of people live in rural areas and less-developed countries and they rely on wells and other potentially untreated sources of water for drinking, cooking and cleaning. However, these sources are at a high risk of contamination. Often when one hears the words water contamination it is assumed to come in the form of biological sources, such as bacteria, protozoa or parasire. Indeed, this is a major concern and has led organisations like the United Nations Children's Fund (UNICEF) and the World Health Organization (WHO) to campaign for the drilling of deep water well because they are less likely to be contaminated with waterborne diseases. However, the move to deeper wells and the growing availability of private wells in places where economic conditions improved has resulted in the uncovering of a hidden health problem–arsenic poisoning. Unlike biological waterborne diseases, such as cholera or dysentery, arsenic is a chemical contaminant of water. Arsenic is naturally found in clay sediments and can leak into well-water regardless of the depth. Consequently, widespread arsenic contamination has occurred around the world, and, in particular, in several regions in Asia. It can be difficult to know if and when a water source is contaminated with arsenic because unless the dose is high the common symptoms associated with poison or waterborne disease, such as abdominal pain, vomiting or diarrhoea, do not occur. But, even at lower doses arsenic causes serious long-term health problems, including skin lesions and cancer. Therefore, wells must be tested before they are used and this testing must continue periodically throughout the lifetime of the well. This is of course difficult in resource-poor settings and in the cases of private wells, government- or NGO-assisted screening programmes may not cover all wells. These two factors have made arsenic contamination a widespread and often unknown health issue for many. Takahiko Yoshida, professor at the Asahikawa Medical University in Hokkaido, Japan, has studied this problem for decades. Yoshida and his colleagues are focused on prevention measures, but they stress that a better understanding of the chronic and long-term health effects of arsenic poisoning is first required.

Formation of active Fe(OH)3 in situ for enhancing arsenic removal from water by the oxidation of Fe(II) in air with the presence of CaCO3

The wide-spread arsenic contamination is considered one of the most global serious environmental issues in the world. In this work, enhanced arsenic removal from water by the oxidation of FeSO4 with CaCO3 in air was investigated and the mechanisms were discussed. Oxidation of Fe(II) into Fe(OH)3 in air became possible in the presence of CaCO3, of which the hydrolyzed OH− from CaCO3 changed the conversion route of Fe(II) to Fe(OH)3. Freshly generated Fe(OH)3 in situ presented high activity for arsenic removal, with Fe/As molar ratio at 2 giving the removal rate of 99.93% and low remaining concentration of 0.035 mg/L from 50 mg/L initial concentration. Precipitation products were characterized by a set of analytical methods including XRD, XPS and Raman analyses to confirm the existence of ferric arsenate phase. Different from using Ca(OH)2 with enough OH− group, the slow hydrolysis of CaCO3 resulted in a continuous generation of fresh Fe(OH)3 for arsenate precipitation and could avoid its rapid transformation into stable FeOOH of large particle size to lose the activity. Aging the ferric compositions by prolonged agitation of Fe(II) and CaCO3 before with arsenate solution confirmed the growth of FeOOH and resulted in a rapid decrease in the capacity for arsenic removal. The observed phenomena were interpreted based on the difference between the precipitation by fresh Fe(OH)3 and the adsorption by large crystalline particles of FeOOH. Controlling the forming speed of ferric composition from Fe(II) with the addition of solid CaCO3 to maintain a fresh state as an easy operation could enhance tremendously its efficiency for As removal, with the ever highest capacity of 248 mg/g among iron absorbents.

Exposure to Arsenic Alters the Microbiome of Larval Zebrafish.

Exposure to environmental toxins such as heavy metals can perturb the development and stability of microbial communities associated with human or animal hosts. Widespread arsenic contamination in rivers and riparian habitats therefore presents environmental and health concerns for populations living near sources of contamination. To investigate how arsenic affects host microbiomes, we sequenced and characterized the microbiomes of twenty larval zebrafish exposed to three concentrations of arsenic that are found in contaminated water—low (10 ppb), medium (50 ppb), and high (100 ppb) for 20 days. We found that even a small concentration of arsenic changed the overall microbial composition, structure and diversity of microbial communities, causing dysbiosis in developing larval zebrafish microbiota. In addition, we found that a high concentration of arsenic also increased the abundance of a class 1 integron, an integrase-dependent system facilitating the horizontal transfer of genes conferring resistance to heavy metals and antibiotics.

Significant Arsenic Reduction by Pond Sediment Microflora in the Arsenic-Affected Bengal Delta

ABSTRACTBiogeochemical reduction and mobilization of sediment-bound arsenic have triggered widespread groundwater arsenic contamination and public health emergency in Bengal Delta. The present study examines arsenic reduction ability of pond sediment microbiota and their diversity from arsenic-affected villages. Arsenic reduction ability of pond sediment microbiota and individual bacterial isolates were studied in sediment microcosm and in culture medium. Arsenic-reducing strains were identified from 16S rDNA sequences. Pond sediment microflora caused profuse arsenic reduction under anoxic and partial anoxic conditions, and under the influence of labile organic matter. Prominent arsenic-reducing strains were identified as Chryseobacterium sp., Pseudomonas sp., Acinetobacter sp., and Comamonas aquatica. The presence of partial-to-true anoxic conditions, typical of pond ecosystems in this region and labile organic matter, as well as organic manure applications in ponds for aquaculture, strongly favored arsenic reduction by sediment microflora. The Bengal Delta plain is bestowed with thousands of aquaculture ponds and floodplain wetlands which might act as important sites for microbial reduction and mobilization of arsenic to the groundwater hydrologic system in the region.

Optimization of hybrid renewable energy polygeneration system with membrane distillation for rural households in Bangladesh

Despite the country's rural electrification program, kerosene is the predominant source for lighting, and woody biomass is virtually the only option available for cooking. The rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. Biogas plants and pV are individually impractical to serve both cooking, lighting and water purification systems, and their combined applications are extremely limited. This study considers a holistic approach towards tackling both of these issues via integrated renewable energy-based polygeneration employed at the village level. The polygeneration unit under consideration provides electricity via a pV array and animal and agriculture waste-fed digester, which in turn is coupled to a gas engine. Excess digester gas is employed for cooking and lighting, while waste heat from the process drives a membrane distillation unit for water purification. Technical assessments and optimization have been conducted with HOMER (Hybrid Optimization of Multiple Energy Resources). Results show that daily electricity demand can be met with such a system while simultaneously providing 0.4 m3 cooking fuel and 2–3 L pure drinking water. Cost estimates indicate that this approach is highly favorable to other renewable options. The pay back period of such system is between 3 and 4 years.

Graphene Based Materials for Arsenic Sensing and Removal from Contaminated Water

Environmental pollution especially toxic gases, heavy metal ions and organic pollutants in air and water, caused by industry and agricultural activities, severely threaten ecological balance and human health, and have received extensive attention worldwide. Arsenic contamination of groundwater is a critical problem that affects millions of people across the world and results in severe diseases such as skin or lung cancer and bladder cancer. Widespread arsenic contamination of groundwater has led to a massive epidemic of arsenic poisoning in Asia and America, especially such as India, Bangladesh, Vietnam, Cambodia, Thailand, southwest USA, Canada, Chile, and neighboring countries. Graphene has become a promising material for many different applications, such as nanoelectronic devices, physical, chemical and biochemical sensors, transparent conductive films, clean energy devices, or nanocomposite formulation. Sensing applications using graphene sheets as transducers have experienced a surge in the last few years, especially for gas sensing platforms, or electrochemical sensors, because of the high electrical conductivity of graphene. In this work, we investigate the synthesis of graphene by methane decomposition at 1000 °C onto free standing electrodeposited substrates, studying the effects of the electrochemical synthesis onto graphene quality. The growth of good quality graphene layers is also discussed in terms of the role played by grain boundaries and diffusion at the grain boundaries. As an advance of graphene studies, 2D graphene nanomaterials have been applied to arsenic sensing and removal from contaminated water. The work will discuss our latest studies and progresses on the application of graphene-based materials in the environmental protection and detection for arsenic contaminated waters. The work will present the use of graphene based electrodes for electrochemical sensing of arsenic; a similar approach will be discuss for arsenic removal, discussing kinetics and performances of the process.

Recent advances in arsenic bioavailability, transport, and speciation in rice.

Widespread arsenic (As) contamination in paddy rice (Oryza sativa) from both geologic and anthropogenic origins is an increasing concern globally. Substantial efforts have been made to elucidate As transformation and uptake processes in rhizosphere and metabolism in rice plant, which provides an essential foundation for the development of mitigation strategies. However, a range of crucial mechanisms from As mobilization in rhizosphere to transport to grains remain poorly understood. To provide new insight into the underlying mechanisms of As accumulation in rice, a range of new perspectives on As bioavailability, transport pathways, and in situ speciation are reviewed here. Specifically, the prominent effects of water regime, Fe plaque, and biochar on As mobilization in rice rhizosphere are discussed critically. An updated understanding of arsenite (AsIII) and methylated As transport from root to vascular bundle and grain is integrated and discussed in detail. Special attention is given to As speciation and distribution in rice grain with potential coping strategies being provided and discussed. Future research priorities are also identified. The new insight into As bioavailability, transport and speciation in rice would lead to a better understanding of As contamination in rice. They would also provide useful strategies from agronomic measures to genetic engineering for more effective restriction of As transport and accumulation in food chain.

Residential Exposures to Arsenic and Hexavalent Chromium from CCA Wood

Residential Exposures to Arsenic and Hexavalent Chromium from CCA WoodAbstract Number:1551 Ky Gress* and Lena Ma Ky Gress* University of Florida, United States, E-mail Address: [email protected] Search for more papers by this author and Lena Ma University of Florida, United States, E-mail Address: [email protected] Search for more papers by this author AbstractArsenic exposure from wood treated with chromated copper arsenate (CCA) remains a concern due to its presence around homes. These studies explored exposure to arsenic (As) and hexavalent chromium (CrVI) from CCA wood in several settings, including children’s exposure outside apartment buildings, homeowner’s exposure from power-washing CCA decking and animal exposure from living in zoo enclosures made from CCA wood. Children’s exposure to As from 2-story staircases was estimated through determination of bioaccessible soil As and wipe sampling of dislodgeable arsenic (DA) on hand railings, steps and surfaces of objects stored under staircases. Total As concentrations in soil samples ranged from 1.2–66.6 mg/kg. Lifetime average daily doses from ingestion of DA and soil ranged from 8.1 × 10-6 to 3.0 × 10-5 mg/kg/day. In Florida, homeowners typically powerwash CCA wood using bleach solutions, which can oxidize CrIII to CrVI, a known carcinogen. This study evaluated potential exposures to As and Cr(VI) on the wood surface, in rinsate and in nearby soil, finding concentrations of As in rinsate up to 1.6 mg/L. CCA wood is commonly found on farms and in zoos. Captive animals living in enclosures made from CCA wood can be in constant contact with arsenic-contaminated soil. Soil sampling inside animal enclosures at a zoo in Florida found widespread arsenic contamination, with concentrations up to 9 times higher than allowed at industrial sites. This study is ongoing and includes biomonitoring of animals, including endangered species in a captive breeding program.

Arsenic exposure in drinking water: an unrecognized health threat in Peru.

To assess the extent of arsenic contamination of groundwater and surface water in Peru and, to evaluate the accuracy of the Arsenic Econo-Quick(™) (EQ) kit for measuring water arsenic concentrations in the field. Water samples were collected from 151 water sources in 12 districts of Peru, and arsenic concentrations were measured in the laboratory using inductively-coupled plasma mass spectrometry. The EQ field kit was validated by comparing a subset of 139 water samples analysed by laboratory measurements and the EQ kit. In 86% (96/111) of the groundwater samples, arsenic exceeded the 10 µg/l arsenic concentration guideline given by the World Health Organization (WHO) for drinking water. In 56% (62/111) of the samples, it exceeded the Bangladeshi threshold of 50 µg/l; the mean concentration being 54.5 µg/l (range: 0.1-93.1). In the Juliaca and Caracoto districts, in 96% (27/28) of groundwater samples arsenic was above the WHO guideline; and in water samples collected from the section of the Rímac river running through Lima, all had arsenic concentrations exceeding the WHO limit. When validated against laboratory values, the EQ kit correctly identified arsenic contamination relative to the guideline in 95% (106/111) of groundwater and in 68% (19/28) of surface water samples. In several districts of Peru, drinking water shows widespread arsenic contamination, exceeding the WHO arsenic guideline. This poses a public health threat requiring further investigation and action. For groundwater samples, the EQ kit performed well relative to the WHO arsenic limit and therefore could provide a vital tool for water arsenic surveillance.

Arsenic Waste Management: A Critical Review of Testing and Disposal of Arsenic-Bearing Solid Wastes Generated during Arsenic Removal from Drinking Water

Water treatment technologies for arsenic removal from groundwater have been extensively studied due to widespread arsenic contamination of drinking water sources. Central to the successful application of arsenic water treatment systems is the consideration of appropriate disposal methods for arsenic-bearing wastes generated during treatment. However, specific recommendations for arsenic waste disposal are often lacking or mentioned as an area for future research and the proper disposal and stabilization of arsenic-bearing waste remains a barrier to the successful implementation of arsenic removal technologies. This review summarizes current disposal options for arsenic-bearing wastes, including landfilling, stabilization, cow dung mixing, passive aeration, pond disposal, and soil disposal. The findings from studies that simulate these disposal conditions are included and compared to results from shorter, regulatory tests. In many instances, short-term leaching tests do not adequately address the range of conditions encountered in disposal environments. Future research directions are highlighted and include establishing regulatory test conditions that align with actual disposal conditions and evaluating nonlandfill disposal options for developing countries.

Emerging Challenges for the Management of Arsenic-Induced Lung Cancer

243 ISSN 1758-1966 10.2217/LMT.12.37 © 2012 Future Medicine Ltd Lung Cancer Manage. (2012) 1(4), 243–246 Arsenic is a well-established human carcinogen. Due to its wide distribution throughout the Earth’s crust, arsenic contamination of drinking water and food is a threat to global human health. In fact, arsenic in drinking water has been considered as the largest mass poisoning in mankind, affecting approximately 160 million people in more than 70 countries. Since 1958, the WHO has lowered the maximum allowable arsenic concentration in drinking water from 0.2 to 0.01 mg/l, based on concerns regarding its carcino genicity to humans due to chronic low-dose exposure [101]. Multiple organs are targets for arsenicinduced carcinogenesis, including skin, liver, kidney, bladder and lung. Accumulating data suggest that lung cancer is the main cause of arsenic-related mortality. Evidence for the relationship between arsenic and lung cancer comes mainly from countries where arsenic is a major public health issue, such as in Bangladesh, India, Taiwan, Argentina and Chile. Arsenic can also act synergistically with other lung carcinogens, such as tobacco, increasing the risk of developing lung cancer by 25-times compared with the nonexposed [1,2]. Similar effects have been described in populations chronically exposed to low concentrations of arsenic. For example, in the USA, low-level exposure may contribute to more than 5000 lung cancer cases per year [3]. Lung tumors associated with arsenic are histologically similar to those derived from tobacco smoke. However, based on emerging differences at epidemiological and molecular levels, these tumors might be considered as different biological entities [4]. The widespread arsenic contamination around the world makes this metalloid a major non-tobacco agent associated with lung cancer. Considering the magnitude of

Groundwater quality in Imphal West district, Manipur, India, with multivariate statistical analysis of data

The aim of this paper was to analyze the groundwater quality of Imphal West district, Manipur, India, and assess its suitability for drinking, domestic, and agricultural use. Eighteen physico-chemical variables were analyzed in groundwater from 30 different hand-operated tube wells in urban, suburban, and rural areas in two seasons. The data were subjected to uni-, bi-, and multivariate statistical analysis, the latter comprising cluster analysis (CA), principal component analysis (PCA), and factor analysis (FA). Arsenic concentrations exceed the Indian standard in 23.3% and the WHO limit in 73.3% of the groundwater sources with only 26.7% in the acceptable range. Several variables like iron, chloride, sodium, sulfate, total dissolved solids, and turbidity are also beyond their desirable limits for drinking water in a number of sites. Sodium concentrations and sodium absorption ratio (SAR) are both high to render the water from the majority of the sources unsuitable for agricultural use. Multivariate statistical techniques, especially varimax rotation of PCA data helped to bring to focus the hidden yet important variables and understand their roles in influencing groundwater quality. Widespread arsenic contamination and high sodium concentration of groundwater pose formidable constraints towards its exploitation for drinking and other domestic and agricultural use in the study area, although urban anthropogenic impacts are not yet pronounced.

Arsenic resistance and cycling in earthworms residing at a former gold mine in Canada

Earthworms (Lumbricus castaneous and Dendrodrilus rubidus), their host soils and leaf litter were collected from a former gold mine with widespread arsenic (As) contamination in Nova Scotia, Canada and determined for total and speciated As. Resistance to As toxicity was investigated by measurement of DNA damage in exposed earthworm populations using the comet assay. Arsenobetaine (AB) was observed at low concentration in the earthworms but not in the host soil or leaf litter. Several different organoarsenic species were observed in the leaf litter and only inorganic As was found in the host soils. The results suggest that 1) adaptation to As toxicity in earthworms is widespread and not particular to a single species, 2) AB originates in the earthworm and not the consumed soil or leaf litter and 3) as previously hypothesised (Button et al., 2010), biotransformation of inorganic As to AB is not likely involved in the adaptation.

Studies on Fractionation of Arsenic in Soil in Relation to Crop Uptake

Widespread arsenic (As) contamination in West Bengal and Bangladesh is of great concern as it affects millions of people due to its toxicity. Groundwater, when used for irrigation, helps entry of arsenic into the food chain via a soil-plant-animal continuum. In this study the extent of geo accumulation is measured in order to assess the degree of As contamination in soil. A sequential fractionation study of As revealed the concentration of different arsenic fractions in the order: As held at the internal surfaces of soil aggregates (20.7%) > freely exchangeable As (20.3%) > calcium associated As (18.7%) > chemisorbed As (17%) > residual As (15.7%) > labile As (3.29%). The variation in fractions may be attributed to the mineralogical make-up of soils along with some physicochemical factors. Statistical correlations and path analyses revealed that total and Olsen extractable arsenic (plant available arsenic) are dependent upon the As held at the internal surfaces of soil aggregates and chemisorbed arsenic fraction, which are directly influenced by the mineralogy of these experimental soils. The crop uptake by Kharif rice and mustard grown in these areas also corroborates the above fact. The poor reflection of exchangeable forms of soil arsenic in crop availability revealed that arsenic has undergone transformation via minerals through the continuous use of arsenic-laden water for irrigation.

A Study on Planning Scheme to Improve the Living Environment through Safe Water Supply and Sanitation in a Rural Village in Bangladesh

Safe water supply and sanitation are basic human needs and the basis of sustainable social development. In Bangladesh, an urgent issue related to water supply is wide spread arsenic contamination of groundwater, on which most people in this country rely for drinking water through tube-wells. Although surface water is an alternative drinking water source, low coverage of improved sanitation and lack of appropriate human excreta management causes surface water pollution, which restricts the use of surface water for drinking. Through water quality conservation, safe water supply and improved sanitation should be integrated to obtain the better living environment. In rural areas of Bangladesh, people suffer from disease due to unhygienic environments, and medical expenditures burden family finances. Inappropriate human excreta management also hampers nutrient cycling and leads to soil degradation of farmland threatening agricultural productivity. Therefore, sanitary improvements with appropriate human excreta management relate to safe water supply and poverty alleviation.In this study, a project aiming to improve the living environment through safe water supply and sanitation was undertaken, establishment of a community based organization (CBO) was also incorporated. In the project area, all of the tube-wells were contaminated with arsenic. However, due to limited support from outside, most villagers were drinking arsenic contaminated groundwater. Under previous situations, although people were aware of the health risks of arsenic contamination, willingness to improve their hazardous situation was low due to a lack of prospects for obtaining a safe water supply. The purpose of this study was to present a scheme based on discussions on the locally appropriate technology options that consider continuous community based management. The pond sand filter (PSF) system was selected, PSF increases the local people's concerns on the quality of pond water, which is their drinking water source, and the sand filter targets community based management. Ecological sanitation was combined to prevent pond water pollution.The authors show how the local people have increased their awareness of water and sanitation issues and willingness to improve their living environment after installing the facilities. The results revealed that the present scheme has encouraged the local people to understand the perspectives of an improved living environment, which has accelerated an increase in their willingness to improve living environment.JEL Classification: I18, I38, R11

Risk-Based Evaluation for Meeting Future Water Demand of the Brahmaputra Floodplain Within Bangladesh

A risk-based evaluation is performed for meeting future water demands in the Brahmaputra Floodplain Area within Bangladesh (BFA). This evaluation is carried out using three risk-based performance indicators: reliability, resiliency and vulnerability. The vulnerability indicator has been redefined incorporating the aspect of a supply failure. The analysis includes the impacts of climate change on both water demands and resources, and the generation of synthetic flows of the Brahmaputra River using time series models. The simulated values of the indicators reveal that the expected demand of the BFA up to the year 2050 can be supplied with the proposed Brahmaputra Barrage inside Bangladesh under the ‘no change’ in climatic condition, provided that the groundwater remains usable. However, if groundwater becomes unusable due to widespread arsenic contamination and/or a climate change occurs, it would not be possible to meet the future water demand of the region with high reliability, moderate resiliency and low vulnerability.