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The presence of toxic levels of inorganic arsenic in drinking water is a worldwide problem. Measurement of millions of samples in the field for arsenic is an analytical challenge and the first step to solve the problem. Here, we developed a novel electrochemical arsine sensor and system based on the cell: C(s)/I 3 − I 2 , AsH 3 (g/aq)//I 3 − , I 2 AgI(s)/Ag(s), where I 3 − /I 2 mediated AsH 3 (g/l) oxidation which occurred on the C(s) electrode. The sensor system requires 50 μL of 10 mM iodine solution and a small piece of filter paper placed inside a novel electrochemical cell. The cell exhibited highly efficient arsine mass transport with a limit of detection of 15 μg/L As(III) in water. A mathematical model of mass transfer of AsH 3 (g/aq) and following electrochemical reaction was developed and applied to explain the experimental data. Groundwater samples containing arsenic were measured to prove its utility in a field deployable instrument. [ABSTRACT FROM AUTHOR]

Abstract This paper reports a simple, facile and rapid preparation of 3‑mercapto‑propanoic acid (MPA) modified cellulose filter paper (MPA-Cell paper) for arsenate removal from drinking water. The MPA was covalently grafted to the cellulose filter paper (Cell) by esterification process through the formation of O‑acylisourea intermediate and characterized by the FTIR, SEM, EDS and XPS analyses. The arsenate adsorption efficiency was studied for batch and semi-continuous systems while exploring the adsorption kinetics, isotherm and the effect of pH for the former. The experimental data fitted well with Langmuir, Dubinin-Radushkevich (DR) and pseudo second order kinetic models. The mechanism of adsorption was studied by FTIR spectroscopy utilizing the adsorption isotherm, kinetic model and XPS results. The modified filter paper performed well at nearly neutral pH in arsenate removal through adsorption and demonstrated a significant arsenate uptake capacity of 92.59 mg/g. The DR and FTIR results indicated that the adsorption of arsenate ion occurred through ion exchange process. The MPA-Cell paper could have a potential use as low-cost but efficient commercial adsorbent for arsenate abatement from contaminated drinking water by both batch as well as semi-continuous operating systems. The MPA-Cell paper could purify ground water containing high level of arsenate. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

The article reports on the work of Scott Fendorf to prevent health crisis in south and south east Asia regions due to arsenic contamination. It notes that Fendorf began collaborating with a colleague who had hydrological and geochemical data from the Ganges-Brahmaputra delta in Bangladesh and the Mekong Delta in nearby Cambodia. A physician working for the Cambodia-based nonprofit organization and Cambodian government also collaborated with Fendorf's group work. His group came up with a well array that would first determine water flows, and later allows water and soil monitoring. Fendorf added that it would take more than 100 years for arsenic to travel naturally through river-based sediments to reach the underlying aquifer.

Skin lesion is one of the important health hazards caused by high intake of arsenic through drinking water and diet, and the other hazards include several types of cancers (viz. skin, lung and urinary bladder), ischemic heart disease, hypertension, etc. Two most important biomarkers to measure arsenic intake in a human body are arsenic concentration in urine and hair. The primary interest of this paper is the association between skin lesion and arsenic concentration in hair for participants with chronic arsenic exposure from West Bengal, India, using bivariate regression model based on copula function. The result showed participants with high arsenic concentration in hair had higher incidence of developing skin lesion. Arsenic concentration in hair was significantly higher for the participants with an arsenic concentration in water > 10 mg/L. [ABSTRACT FROM AUTHOR]

In Nepal, arsenic (As) contamination is a major issue of current drinking water supply systems using groundwater and has recently been one of the major environmental health management issues especially in the plain region, i.e., in the Terai districts, where the population density is very high. The Terai inhabitants still use hand tube and dug wells (with hand held pumps that are bored at shallow to medium depth) for their daily water requirements, including drinking water. The National Sanitation Steering Committee (NSSC), with the help of any other organizations, has completed arsenic blanket test in 25 districts of Nepal by analysing 737,009 groundwater samples. Several organizations, including academic institutions, made an effort to determine the levels of arsenic concentrations in groundwater and their consequences in Nepal. The results of the analyses on 25,058 samples tested in 20 districts, published in the status report of arsenic in Nepal (2003), demonstrated that the 23% of the samples were containing 10-50 μg/L of As, and the 8% of the samples were containing more than 50 μg/L of As. Recent status of over 737,009 samples tested, the 7.9% and 2.3% were contaminated by 10-50 μg/L and >50 μg/L, respectively of As. The present paper examines the various techniques available for the reduction of arsenic concentrations in Nepal in combination with the main results achieved, the socio-economic status and the strategies. This paper aims to comprehensively compile all existing data sets and analyze them scientifically, by trying to suggest a common sustainable approach for identifying the As contamination in the nation, that can be easily adopted by local communities for developing a sustainable society. The paper aims also to find probable solutions to quantify and mitigate As problem without any external support. The outcome of this paper will ultimately help to identify various ways for: identify risk areas; develop awareness; adopt the World Health Organization (WHO) guideline; identify alternative safe water sources and assess their sustainability; give priorities to water supply and simple eco-friendly treatment techniques; investigate impacts of arsenic on health and agriculture; strengthen the capability of government, public, Non-governmental Organization (NGO) and research institutions. [ABSTRACT FROM AUTHOR]

Testing of groundwater used for drinking for arsenic has been undertaken more widely by state governments in several states of India in recent years with the support of UNICEF. Available data for five states are collated in this paper and this provides the most up-to-date picture of areas known to be affected by arsenic in groundwater in the Indian portion of the Ganges-Brahmaputra river basin. In West Bengal, water from 132,262 government installed handpumps in 8 districts has been tested and overall 25.5% of samples were found to contain arsenic at concentrations greater than 50 μ gL-1 and 57.9% at concentrations greater than 10 μ gL-1. On the banks of the Brahmaputra in Assam, to date, samples from 5,729 government handpump sources in 22 districts have been tested for arsenic. Overall, samples from 6.3% of sources were found to contain arsenic at concentrations greater than 50 μ gL-1 and 26.1% at concentrations greater than 10 μ gL-1. In Bihar, on the River Ganges upstream of West Bengal, 66,623 sources from 11 districts have been tested and water samples from 10.8% of sources were found to contain arsenic at concentrations greater than 50 μ gL-1 and 28.9% at concentrations greater than 10 μ gL-1. Upstream of Bihar in Uttar Pradesh, home of the Taj Mahal, to date water samples from 20,126 government-installed handpump sources have been tested. As a result 2.4% of the samples tested were found to contain arsenic at concentrations greater than 50 μ gL-1 and 21.5% at concentrations greater than 10 μ gL-1. Finally in one district of Jharkhand, lying on the Ganges alluvial plain between Bihar and West Bengal, 9,007 sources have been tested and water samples from 3.7% of sources were found to contain arsenic at concentrations greater than 50 μ gL-1 and 7.5% at concentrations greater than 10 μ gL-1. State governments have adopted different sampling strategies and these are described in this paper. Testing is ongoing in several states and the complete picture is yet to emerge in some areas. [ABSTRACT FROM AUTHOR]

It has been increasingly recognised that calculation of the disease burden due to populations, such as in Bangladesh, extensively using hazardous arsenic bearing well waters, must explicitly account for the trade-off between diarrhoeal disease incidence and that of arsenic-related diseases. This is because it is likely that moves to alternative drinking water sources, be they surface waters or even more distant groundwaters, without further mitigation would result in a concurrent increase in diarrhoeal disease. In this paper, we update the model of Lokuge[1] of the effects of such arsenic mitigation on disease burden in Bangladesh, using updated population data and background disease estimates. We run a critical pathway analysis on the model using Standardised Mortality Ratios (SMRs) for diabetes mellitus and ischemic heart disease from different epidemiological studies recently reviewed by Navas-Acien.[2, 3] Our analysis agrees with that of Lokuge[1] that mitigation simply involving the substitution of a range of surface waters for well water sources with As > 50 μ g/L would have a net positive impact on disease burden, as determined by deaths and Disability Life Adjusted Years (DALYs). In contrast, however, there is considerable ambiguity in the analogous results for mitigation for all the population exposed to well water with As > 10 μ g/L. Depending upon the data source chosen for diabetes mellitus and ischaemic heart disease SMRs, such mitigation is modelled to have either a positive or a negative net impact on overall disease burden. The modelled negative impacts are entirely commensurate with the rationale for seeking groundwater as an alternative to surface waters as a drinking water supply, and highlight the practical requirement for multiple mitigation strategies, including those directed at ensuring the microbiological safety and continued protection of any alternative water supplies. Our study highlights the need for (i) adequate epidemiological studies involving multiple exposure categories, ideally resulting in an accurate dose-response relationship for arsenic uptake and the non-malignant high incidence conditions diabetes mellitus and ischemic heart disease for individuals with the socioeconomic and nutritional status of the Bangladeshi populations, and (ii) refined estimates of the diarrhoel disease burden arising from usage of surface waters. [ABSTRACT FROM AUTHOR]

The article offers information on several topics related to safety, health and environment of chemical industries in India. It highlights the results of a research study conducted by the World Health Organisation (WHO) mentioning the environmental health risk for air pollution. Development of a foldscope, a microscope printed on paper by research team in Stanford University. Also includes a project on filter arsenic out of drinking water at the University of California.

The paper presents the results of treatment of raw drinking water, loaded with organic substances (COD = 94.68 mg/l) and high concentration of As (up to 38.66 mg/l). The treatment of raw water was carried out by in situ electrochemically synthesized ferrate(VI) in a pilot plant with a flow-through electrochemical cell. For the treatment of water the pilot plant batch type with three reaction columns was formed. The developed method was applied to the treatment of raw water from four different sources. The results showed the removal of up to 97% As, and permanganate index close to the statutory limit value (12 mg/l of KMnO4). [ABSTRACT FROM AUTHOR]

This paper estimates the health costs of arsenic contamination of drinking water in Assam, India, where nearly one million people are affected. Applying the Three Stage Least Square (3SLS) procedure to data collected through a primary survey of 355 households in 2013, it estimates three structural equations to determine health costs due to arsenic contamination. The estimates show that the average annual health cost of a 1 microgram increase in arsenic concentration per liter of drinking water is about INR4 per household. Furthermore, if the average level of arsenic concentration is reduced to the safe limit of 50 microgram per liter, the average annual welfare gain for a household is estimated to be INR 862 (USD 14). Projecting these figures to the entire arsenic-affected population of Assam, the annual health costs of a 1 microgram increase in arsenic concentration per liter are estimated to be about INR 0.76 million (USD 0.01 million) and the welfare gains from reducing the level of arsenic concentration to the safe limit are estimated to be INR 153 million (USD 2.49 million). The results also indicate that these health costs and welfare gains vary significantly across different levels of arsenic concentration and across districts. Finally, the paper draws policy implications for providing safe drinking water in Assam. [ABSTRACT FROM AUTHOR]

Arsenic testing work has been carried out in Uttar Pradesh by UP Jal Nigam during the period 2005–2008. During this period, arsenic testing was performed using field test kits for 150,000 sources employing screening and blanket testing approach. The current paper describes the work of geographical information system (GIS) mapping in Bahraich district. The district has two physiographic units – Uprahar and Tarhar to depict highland and lowland Quarternary alluvial plains. Out of 30,216 India Mark II hand pumps in the district, arsenic testing was performed, by UP Jal Nigam for 13,812 hand pumps, out of which 7190 (52.06%) tested sources show arsenic value > 0 μg/L. Further segregation of data shows that 56.66% of affected sources fall in 10–40 μg/L category and 10.86% sources fall in >50 μg/L category. Village level mapping of affected sources at GIS platform shows arsenic concentration is more in Huzoorpur and Tajwapur blocks which lie in lowland physiographic unit. [ABSTRACT FROM PUBLISHER]

This paper focuses on determining an efficient and simple method to remove arsenic from groundwater. Arsenic is a naturally occurring element widely distributed in the earth's crust. Arsenic is very toxic when found in large quantities in drinking water. This report documents the selected treatment method and laboratory experimentation of arsenic removal from drinking water in small water delivery systems and domestic water systems. The objective is to expand upon research of new and existing arsenic removal technologies or promote a new, alternative process. Several treatment technologies have been considered to perform this function, but cost and reliability concerns prompted the decision to analyze small-scale, community-based filtration units, specifically. Based upon initial test data, the use of dual treatment method comprising of oxidation-coagulation-filtration and adsorption by activated alumina has proven to be more economic having more capacity and superior reliability as compared to other arsenic removal processes using various other media. [ABSTRACT FROM AUTHOR]

Elevated levels of arsenic in drinking water are found in several parts of Asia. Prolonged intakes of even low concentrations typically have serious health effects. This research paper integrates results of various studies on arsenic contamination of ground, surface, waste and drinking water in north-central Mongolia. Samples were analyzed with the ARSOlux biosensor and the Arsenator field test kit as well as different spectrometric methods (ICP-MS, ICP-OES). Altogether 309 samples were tested for their arsenic concentration, 44 of them with more than one technique. In the study region, the enrichment of heavy metals in surface waters is often linked to mining and coal combustion. The highest concentration of arsenic (As) was detected in the effluent of a gold mine (up to 2,820 μg L) and in the ash basin of a thermal power plant (up to 1,170 μg L). Five of 54 drinking water samples and 16 of 184 river samples were found to contain As levels above the World Health Organization (WHO) maximum permissible limit (10 μg L), with a maximum of 300 μg L As. In addition, elevated levels of uranium were detected. The degree and extent of As concentrations exceeding WHO standards were previously unknown and demonstrate the necessity for a more intensive screening as well as possible interventions concerning the intake of arsenic-contaminated drinking water. Preliminary results indicate that the ARSOlux biosensor technology is well suited for a precise quantification of arsenic content at low detection limits in regions where access to central laboratories is difficult. [ABSTRACT FROM AUTHOR]

This paper describes the development of a remediation approach based on the pre-oxidation using Fenton's reagent and the subsequent removal of arsenic (As) through sand filtration from drinking water. The efficiency of the process was carried out including As(III) and As(V) with various concentration ratios up to 3,000 ppb. Efficient removal of As was observed within WHO guideline value of 10 ppb. The recoveries of samples were found to be 98 % ± 2.5 %. The process was applied to field samples, where results show considerable reduction in As concentrations. This process is cost effective for treatment of drinking water with high concentration of As. [ABSTRACT FROM AUTHOR]

Arsenic is present in environment in trace amounts in rocks, soil, water and air but its toxicity effects are highly dependent on its chemical forms; inorganic and organic. There is a direct association between elevated arsenic exposure through drinking water and prevalence of different types of cancers. Present review describes the brief account of arsenic chemistry with reference to water and environment which is relevant to its toxicity arising out of different arsenic species and finally its remediation technologies. The quantification of arsenic species is difficult owing to the low concentration of arsenic in drinking water which is relatively lower than detection limits of modern analytical methods. New hyphenated techniques with more advanced tools have therefore, been discussed in the present paper which are being used in arsenic speciation analysis. The present review also highlights the importance to identify and quantify each chemical species of arsenic as more than 20 arsenic compounds are present in natural environment and in biological systems. Below microgram per liter detection limits are required to quantify arsenic species from these systems and a combination of chromatographic separation with atomic spectroscopy and mass spectroscopic detection is therefore, the most suitable speciation choice. The second important criteria viz. arsenic remediation from contaminated water for supply of safer drinking water is discussed and various remediation technologies are reviewed. [ABSTRACT FROM AUTHOR]

Nanoscale zero-valent iron (NZVI) is increasingly gaining interest as an efficient sorbent for various types of aqueous pollutants. This paper examined the potential for using laboratory synthesized NZVI particles (∼40 nm, 49.2 m2/g) to remove arsenite [As(III)] from drinking water. Batch experiments were conducted to study the removal kinetics, sorption isotherms, and the effect of anions or heavy metal ions on arsenic removal with NZVI. NZVI demonstrated very rapid adsorption and large capacity for the removal of As(III). The maximum As(III) adsorption capacity in batch experiments calculated by Langmuir adsorption isotherm was 76.3 mg/L of As(III)/g of NZVI. The reduction of As(III) followed a pseudo-first-order kinetics that the rate constants (k SA) was 3.42 mL/m2 min. This study suggests that implementation of NZVI for remediation of As(III) from drinking water is sufficient. [ABSTRACT FROM AUTHOR]

Fluoride (F) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F in the groundwater, after understanding the chemical behavior of F in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F-bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F; the concentration of TH is more than the concentration of TA at low F groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F has CH. As a result, the F has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO and a reduction of TH, and thereby a dissolution of F. Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F. Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F in the groundwater. [ABSTRACT FROM AUTHOR]

Arsenic is a metalloid, that is, considered to be a human carcinogen. Millions of individuals worldwide are chronically exposed through drinking water, with consequences ranging from acute toxicities to development of malignancies, such as skin and lung cancer. Despite well-known arsenic-related health effects, the molecular mechanisms involved are not fully understood; however, the arsenic biotransformation process, which includes methylation changes, is thought to play a key role. This paper explores the relationship of arsenic exposure with cancer development and summarizes current knowledge of the potential mechanisms that may contribute to the neoplastic processes observed in arsenic exposed human populations. [ABSTRACT FROM AUTHOR]

High dose arsenic in drinking water (≥100 μg L−1) is known to induce lung cancer, but lung cancer risks at low to moderate arsenic levels and its dose–response relationship remains inconclusive. We conducted a systematic review of cohort and case-control studies that quantitatively reported the association between arsenic concentrations in drinking water and lung cancer risks by searching the PubMed database till June 14, 2018. Pooled relative risks (RRs) of lung cancer associated with full range (10 μg L−1–1000 μg L−1) and low to moderate range (<100 μg L−1) of water arsenic concentrations were calculated using random-effects models. A dose–response meta-analysis was performed to estimate the pooled associations between restricted cubic splines of log-transformed water arsenic and the lung cancer risks. Fifteen studies (9 case-control and 6 cohort studies) involving a total of 218 481 participants met the inclusion criteria. Meta-analysis identified significantly increased risks of lung cancer on exposure to both full range (RR = 1.21; 95% confidence interval [CI] = 1.05–1.37; heterogeneity I2 = 54.3%) and low to moderate range (RR = 1.18; 95%CI = 1.00–1.35; I2 = 56.3%) of arsenic-containing water. In the dose–response meta-analysis of eight case-control studies, we found no evidence of non-linearity, although statistical power was limited. The corresponding pooled RRs and their 95%CIs for exposure to 10 μg L−1, 50 μg L−1, and 100 μg L−1 water arsenic were 1.02 (1.00–1.03), 1.10 (1.04–1.15), and 1.20 (1.08–1.32), respectively. We provide evidence on the association between increased lung cancer risks and inorganic arsenic in drinking water across low, moderate and high levels. Minimizing arsenic levels in drinking water may be of public health importance. [ABSTRACT FROM AUTHOR]

In this paper we have presented a unique low cost arsenic removal technique using ferric hydroxide microcapsule-loaded alginate beads (FHMCA) as an adsorbent in a continuous packed column. The microencapsulated particles of ferric hydroxide were produced in a spray dryer and subsequently coated with calcium alginate to form spherical beads of about 2 mm diameter. Batch experiments were conducted with these beads to generate isotherm data. The loading capacity was found to be 3.8 mg arsenic/gm of adsorbent. The experimental data conformed to Freundlich adsorption isotherm. A generalized mathematical model was also developed and the visual basic codes run with the physical parameters of the adsorbent and isotherm data that were evaluated experimentally was achieved for a continuous 75 days' operation. The safe disposal of the spent adsorbent was confirmed by the toxicity characteristic leaching procedure (TCLP) results. With known set of physical parameters of the adsorbent, input water flow rate and its arsenic concentration, the model could predict the number of days the column would run with output below a specific arsenic concentration. [ABSTRACT FROM AUTHOR]

Abstract: The measurement of inorganic arsenic in the environment has received considerable attention over the past 40+ years due to its toxicity and prevalence in drinking water. This paper provides an overview of voltammetric techniques used since 2001. More than fifty papers from refereed analytical chemistry journals on the speciation and measurement of inorganic arsenic (As(III) and As(V)) in practical and environmental samples are included. The present review shows that stripping voltammetry is a sensitive and inexpensive technique. The new approaches include development of novel measurement protocols through media variation, development and use of new boron doped diamond electrodes modified with metals, nano Au-modified electrodes on carbon or carbon nano-tubes, novel rotating disc and vibrating electrodes to enhance mass transfer, and modified Hg(l) and thin film Bi on carbon for cathodic stripping voltammetry are discussed. Although, majority of the papers were of exploratory in nature, the trend towards developing a commercial standalone instrument for field use is still in progress. [Copyright &y& Elsevier]

In recent years field test kits have been largely used to identify arsenic (As) levels in contaminated water sources in Bangladesh, West Bengal (India), and elsewhere in the world to establish whether or not the water is safe. Most of the kits are based on the reaction of arsine gas with some chemical agent to form a coloured complex; the intensity of the colour is compared visually with a colour-coded chart or measured electronically to calculate the concentration of As in the water sample. In this paper, a step-wise review is presented of the analytical process used in the most commonly available As field test kits and the associated shortcomings of each of these kits. We also identify the research gaps for future work to enhance the accuracy and reliability of test results produced by these kits. [ABSTRACT FROM AUTHOR]

Arsenic poisoning has become one of the major environmental worries worldwide, as millions of people, which have been exposed to high arsenic concentrations (through contaminated drinking water), developed severe health problems. The high toxicity of this element made necessary the enforcement of stringent maximum allowable limits in drinking water. So, the development of novel techniques for its removal from aqueous streams is a very important issue. This paper offers an overview of geochemistry, distribution, sources, toxicity, regulations and applications of selected techniques for arsenic removal. The contribution briefly summarizes adsorption processes and mechanism of arsenic species removal from water streams by means of iron oxide/oxyhydroxide based materials. Sorption capacities of various sorbents (e.g. akaganeite, goethite, hydrous ferric oxide, iron oxide coated sand, Fe(III) loaded resin, granular ferric hydroxide, Ce(IV) doped iron oxide, natural iron ores, iron oxide coated cement, magnetically modified zeolite, Fe-hydroxide coated alumina) have been compared. [ABSTRACT FROM AUTHOR]

A Participatory Geographical Information System (PGIS) has been developed recently to design and adapt Geographic Information System (GIS) that draws on the diversity of experiences associated with "participatory development" and involves communities in the production of GIS data and spatial decision-making tools. Participatory approach in the development of GIS helps to develop local knowledge processes. This knowledge process creates a channel of coordination between local people and the experts. The paper deals with the possibility of using spatial maps in consultation with local communities to develop an effective and sustainable distribution planning to maximize as well as ensure safe water coverage for the arsenic (As) exposed population in Matlab Upazila in southeastern Bangladesh. Participatory Rural Appraisal (PRA) methods along with GIS were used to obtain relevant information from the field. Participants from different focus-groups were asked to determine their "own priorities" for spatial planning of alternative As-safe drinking water options. The study reveals that about 70% of the alternative safe water options were distributed after consultation with people. These distributed options were found to be superimposed within the existing safe water buffer zones which otherwise could have been avoided and thus increased the safe water coverage if the spatial maps were also consulted before selection of final installation sites. The study based on the community perspectives on demand-based safe water options thus reveals the suitability of using PGIS techniques for rational distribution of safe water options. The process of participatory mapping within focus-groups further makes a platform to enhance information about community needs of suitable safe water options in the study area. [ABSTRACT FROM AUTHOR]

The objective of this study is to analyze health effects of arsenic pollution of drinking water using a geographical information system (GIS). The paper reports the regional impact of arsenic contamination in six administrative blocks of the central part of the Murshidabad district, West Bengal, India. In this area about 1,248,580 people are exposed to arsenic pollution out of whom 388,316 people are exposed to arsenic concentrations above 0.05 mg/L, the WHO maximum permissible level of arsenic in drinking water. The study estimates that 65% of the total area of the six blocks has arsenic concentrations below 0.05 mg/L, 26.12% of the area has arsenic concentrations above 0.05 mg/L, and for the rest of the area no arsenic distribution data available. The total number of expected death cases has been estimated considering the percent of risk involved in a concentration range and corresponding total population using such water for drinking purpose. The analysis forecasts that 11,890 people may risk death due to arsenic pollution in the whole life span. The maximum number of death cases is expected in Domkal and Beldanga 1 blocks and the minimum number of death cases is expected in Block Bhagabangola 2. This study also reports a comparison between the theoretical expectation of death cases and actual reported arsenicosis cases for the Domkal block. The areas of theoretical expectation and the areas of actually reported cases match fairly well except in a few cases. The present study helps planning and implementing of priority-based arsenic mitigation options. [ABSTRACT FROM AUTHOR]

Environmental exposure to arsenic (As) in terms of public health is receiving increasing attention worldwide following cases of mass contamination in different parts of the world. However, there is a scarcity of data available on As geochemistry in Brazilian territory, despite the known occurrence of As in some of the more severely polluted areas of Brazil. The purpose of this paper is to discuss existing data on As distribution in Brazil based on recent investigations in three contaminated areas as well as results from the literature. To date, integrated studies on environmental and anthropogenic sources of As contamination have been carried out only in three areas in Brazil: (1) the Southeastern region, known as the Iron Quadrangle, where As was released into the drainage systems, soils and atmosphere as a result of gold mining; (2) the Ribeira Valley, where As occurs in Pb-Zn mine wastes and naturally in As-rich rocks and soils; (3) the Amazon region, including the Santana area, where As is associated with manganese ores mined over the last 50 years. Toxicological studies revealed that the populations were not exposed to elevated levels of As, with the As concentrations in surface water in these areas rarely exceeding 10 μg/L. Deep weathering of bedrocks along with formation of Fe/Al-enriched soils and sediments function as a chemical barrier that prevents the release of As into the water. In addition, the tropical climate results in high rates of precipitation in the northern and southeastern regions and, hence, the As contents of drinking water is diluted. Severe cases of human As exposure related to non-point pollution sources have not been reported in Brazil. However, increasing awareness of the adverse health effects of As will eventually lead to a more complete picture of the distribution of As in Brazil. [ABSTRACT FROM AUTHOR]

At present, about 80 million people in Bangladesh are at risk of losing their health and having a sharply reduced life expectancy as a result of exposure to excessive arsenic through drinking water from tube wells. In this article, we build a multi-objective mixed-integer optimisation model, which we can simulate. We identify efficient loci of the trade-off between the several competing objectives in order to provide safe water to the affected people. Three types of simulation cases are discussed. For each case, a different type of safe water was chosen as optimal. [ABSTRACT FROM AUTHOR]

The US Environmental Protection Agency recently set a new maximum contaminant level (MCL) for arsenic in drinking water of 10 μg/l. In this paper, we review the completeness and accuracy of drinking water arsenic occurrence data in the United States and identify populations exposed to elevated arsenic concentrations that would be suitable for epidemiological studies of arsenic health effects. Using existing data from the Environmental Protection Agency Arsenic Occurrence and Exposure Database and additional data from state health and environment departments and water utilities, we identified 33 counties in 11 states with an estimated mean drinking water arsenic concentration of 10 μg/l or greater. A total of 11 of these 'confirmed' counties had an estimated mean arsenic concentration of 20 μg/l or more and two had an estimated mean arsenic concentration 50 μg/l or more. Based on census data, between 1950 and 1999 there were approximately 51.1 million person-years of exposure to drinking water arsenic at levels of 10 mg/l or more, 8.2 million at levels of 20 μg/l or more arsenic and 0.9 million at levels of 50 μg/l or more. Mortality and incidence of diseases known to be associated with arsenic exposure can and should be examined in these counties as part of a comprehensive assessment of arsenic health effects in US populations. [ABSTRACT FROM AUTHOR]

This article provides updated status of the arsenic affected rural habitations in India, summarizes the policy initiatives of the Ministry of Drinking Water & Sanitation (Government of India), reviews the technologies for arsenic treatment and analyses the progress made by states in tackling arsenic problems in rural habitations. It also provides a list of constraints based on experiences and recommends suggested measures to tackle arsenic problems in an holistic manner. It is expected that the paper would be useful for policy formulators in states, non-government organizations, researchers of academic and scientific institutions and programme managers working in the area of arsenic mitigation in drinking water, especially in developing countries, as it provides better insights compared to other available information in India on mitigating arsenic problems in drinking water in rural areas. [ABSTRACT FROM AUTHOR]

The article presents abstracts on papers related to "Arsenic exposure from drinking water, and all-cause and chronic-disease mortalities in Bangladesh (HEALS): a prospective cohort study," by M. Argos and colleagues, "Mercury exposure and risk of cardiovascular disease in two U.S. cohorts," by Mozaffarian and colleagues, and "Health Effects of Energy Drinks on Children, Adolescents, and Young Adults," by S. M. Siefert and colleagues.

Arsenic from drinking water is a well-known risk factor for bladder cancer. The purpose of this paper is to systematize some important yet often overlooked facts considering the relationship between arsenic exposure and the occurrence of bladder cancer. Since the exposure to inorganic arsenic from food, inhaled air, and skin absorption as well as arsenic methylation ability are not fully investigated, our assumption is that the exposure of arsenic only from drinking water is underestimated and its role as a risk factor is highly overestimated, This paper proposes some qualitative and quantitative parameters of arsenic as a risk factor for bladder cancer, The recommended qualitative parameters of arsenic intake are first, pathways of exposure, and second, toxicity and metabolism. The suggested quantitative parameters of arsenic intake include amounts of arsenic absorbed in the body, duration of arsenic exposure, and duration of arsenic presence in the urinary bladder. This approach can be implemented in a systematic classification and explanation of various risk factors and their mutual interactions for other types of cancer or diseases in general. [ABSTRACT FROM AUTHOR]

Arsenic (As) causes acute and chronic toxicity, it harm the skin and associated with increase risk of cancer in the skin, bladder and kidney. It is very difficult to diagnose the early symptoms of arsenicosis so it depends largely on awareness with improving the quality of drinking water. There are several methods are available for removal of As from water. The most commonly used technologies are oxidation, co-precipitation, adsorption, absorption, coagulation, ion-exchange resin, lime treatment and membrane techniques. Now today the safe disposal of large quantity of As contaminated sludge generated from As removal water treatment plant which contain about 5-7kg of arsenic per cubic meter due to risk of underground water contamination as arsenic has very high leaching potential. For safe disposal of solid hazardous waste of As requires treatment. A long term solution appears to solidification/stabilization (s/s) of As-sludge and using it for beneficial purposes like bricks and concretes etc. In the field of active research, this paper identifies the gap between the implementation of process as well as new technologies for safe disposal of arsenic sludge. [ABSTRACT FROM AUTHOR]

Arsenic in drinking water resources and, especially, in groundwater, represents a severe health problem for millions of people in affected regions. This paper investigates a removal technology combining non-thermal plasma at a reaction time of 30 min, which has improved the downstream coagulation and the filtration efficiency. The results show removal rates of total arsenic over 98%. In addition, WHO limits of less than 10 μ g L − 1 could be achieved in both batch and continuous set-ups. A difference in effective over potential of the NTP reaction of 32 m V over a reaction using air as oxidant was calculated. Kinetic data of arsenic concentrations over time fitted a pseudo first-order reaction. The proposed process combination has shown to be a simple and energy-saving alternative compared to conventional oxidation and adsorption technologies by exploiting the 'enhancer' effect of ozone and other reactive oxygen species within the NTP. [ABSTRACT FROM AUTHOR]

Arsenic is a naturally occurring class 1 human carcinogen that is widespread in private drinking water wells throughout the province of Nova Scotia in Canada. In this paper we explore the spatial variation in toenail arsenic concentrations (arsenic body burden) in Nova Scotia. We describe the regional distribution of arsenic concentrations in private well water supplies in the province, and evaluate the geological and environmental features associated with higher levels of arsenic in well water. We develop geostatistical process models to predict high toenail arsenic concentrations and high well water arsenic concentrations, which have utility for studies where no direct measurements of arsenic body burden or arsenic exposure are available. 892 men and women who participated in the Atlantic Partnership for Tomorrow's Health Project provided both drinking water and toenail clipping samples. Information on socio-demographic, lifestyle and health factors was obtained with a set of standardized questionnaires. Anthropometric indices and arsenic concentrations in drinking water and toenails were measured. In addition, data on arsenic concentrations in 10,498 private wells were provided by the Nova Scotia Department of Environment. We utilised stepwise multivariable logistic regression modelling to develop separate statistical models to: a) predict high toenail arsenic concentrations (defined as toenail arsenic levels ≥ 0.12 μg g − 1 ) and b) predict high well water arsenic concentrations (defined as well water arsenic levels ≥ 5.0 μg L − 1 ). We found that the geological and environmental information that predicted well water arsenic concentrations can also be used to accurately predict toenail arsenic concentrations. We conclude that geological and environmental factors contributing to arsenic contamination in well water are the major contributing influences on arsenic body burden among Nova Scotia residents. Further studies are warranted to assess appropriate intervention strategies for reducing arsenic body burden among human populations. [ABSTRACT FROM AUTHOR]

It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long-term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic-containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification. [ABSTRACT FROM AUTHOR]

Contaminated groundwater with a high concentration of arsenic continues to pose health threats to millions of people worldwide, especially in Asia. As(iii) is the dominant arsenic species in groundwater, and is more toxic, soluble, and mobile than As(v). Affected communities need accessible technologies to remove As(iii) from drinking water, especially in rural areas. In this study, a strategy is adopted to assemble small-sized magnetic MnFe2O4 nanocrystal building blocks to form mesoporous clusters (NCs) with the advantage of increasing the magnetization while retaining superparamagnetic characteristics by using a solvothermal method, which is beneficial for efficient separation from treated water by a moderate magnetic field. The MnFe2O4 NCs combined with uniform mesoporous structure and small constituent nanocrystals (about 8–12 nm in size) provides a synergistic effect for enhanced adsorption performance toward As(iii) with an adsorption capacity (＞27.27 mg g−1) under neutral conditions. The analysis of Fourier transformed infrared spectra and X-ray photoelectron spectroscopy demonstrates that the adsorption of As(iii) on MnFe2O4 NCs is through the formation of a surface complex. [ABSTRACT FROM AUTHOR]

This article proposes an alternative to increase the reliability and reproducibility of a colorimetric method to measure arsenic (As) concentrations. The method of analysis developed incorporates a digital analysis technique to eliminate the operator dependence of results, and As concentrations are quantitatively determined from digital levels computed from photographs of the colorimetric reaction that emerges during the test. This technique allows the sensitivity of the detection to be increased at low concentration ranges, which is of fundamental importance for the detection of As given the current acceptable limit for drinking water. The results obtained show a very good correlation between As concentrations determined by means of analytical laboratory techniques and the method proposed in this research. [ABSTRACT FROM PUBLISHER]

Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7 % of the sampled tube wells contain As concentrations above 10 μg/L, while 57.7 % contain As concentrations above 50 μg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51-99 μg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region. [ABSTRACT FROM AUTHOR]

Prolonged ingestion of arsenic in drinking water can increase the risks of dying of lung and bladder cancer, particularly for smokers. In a survey of arsenic hotspots in the United States, we elicited individuals' subjective mortality risks related to the presence of arsenic in drinking water. Using this data, we address whether smokers perceive mortality risks from this source differently from non-smokers. We find that those who have smoked at some point in their life have significantly higher perceived arsenic mortality risks than those who have never smoked, on average. We also find that the sample group of current smokers has higher average perceived arsenic mortality risks than those who have quit smoking. We model the decision to treat water for arsenic and find some evidence that current smokers are less likely to engage in this mitigating behavior than are ex-smokers or non-smokers even though their perceived risk is higher. We infer that smokers are either less risk averse or have a higher rate of time preference than non-smokers and ex-smokers. ( JEL I0, D81, Q53) [ABSTRACT FROM AUTHOR]

Abstract: Although pump-well is the primary drinking water source in rural areas of China, there are still 8.4% of villages reliant on cold-spring. In this study, a survey of arsenic concentration in cold-springs and pump-wells was carried out in Hui County, Northwest China. A total of 352 drinking water samples, including 177 cold-springs and 175 pump-wells, were collected. The maximum arsenic concentrations in cold-springs and pump-wells were 0.482mg/L and 0.067mg/L, respectively. We found that 15.8% (28) of total cold-springs and 1.1% (2) of total pump-wells had arsenic concentrations exceeding the maximum allowable concentration of arsenic in drinking water of rural China (0.05mg/L). Our findings show that 5 cold spring-contaminated villages are located in the mountainous areas of Hui County and 2224 inhabitants may be at risk of high arsenic exposure. This paper indicates that arsenic contamination of cold-springs may be more serious than expected in mountainous areas of Northwest China and extensive surveys and epidemiological studies should be carried out to investigate the potential contaminated areas and affected population. [Copyright &y& Elsevier]

Abstract: This paper assesses health risks due to the ingestion of inorganic arsenic from fish and shellfish farmed in blackfoot disease areas by general public in Taiwan. The provisional tolerable weekly intake of arsenic set by FAO/WHO and the target cancer risk assessment model proposed by USEPA were integrated to evaluate the acceptable consumption rate. Five aquacultural species, tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), mullet (Mugil cephalus), clam (Meretrix lusoria) and oyster (Crassostrea gigas) were included. Monte Carlo analysis was used to propagate the parameter uncertainty and to probabilistically assess the health risk associated with the daily intake of inorganic As from farmed fish and shellfish. The integrated risk-based analysis indicates that the associated 50th and 95th percentile health risk are 2.06×10−5 and 8.77×10−5, respectively. Moreover, the acceptable intakes of inorganic As are defined and illustrated by a two dimensional graphical model. According to the relationship between C inorg and IR f derived from this study, two risk-based curves are constructed. An acceptable risk zone is determined (risk ranging from 1×10−5 to 6.07×10−5) which is recommended for acceptable consumption rates of fish and shellfish. To manage the health risk due to the ingestion of inorganic As from fish and shellfish in BFD areas, a risk-based management scheme is derived which provide a convenient way for general public to self-determine the acceptable seafood consumption rate. [Copyright &y& Elsevier]

We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (∼ $0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6 × 10- 6mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo-second-order kinetic model, R2 ≥ 0.99) increase from 2.4 × 105 to 7.2 × 105 g mol- 1min- 1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center. [ABSTRACT FROM AUTHOR]

Abstract: The present paper presents results of the study in removal of iron, arsenic and total coliform from drinking water using single-pass constructed soil filter (CSF). Results indicated that arsenic levels ranged from 0.5 to less than 10μgl−1 levels; iron from 5 to less than 0.3mgl−1 and coliform from 10−5 to less than 5CFU/100ml. The results revealed very high removal efficiency, i.e., over 99% and water quality as per WHO standard. [Copyright &y& Elsevier]

Abstract: Chronic arsenic exposure and skin lesions (keratosis and hyperpigmentation) are inextricably linked. This paper was to quantify the children skin lesions risks and to further recommend safe drinking water arsenic standard based on reported arsenic epidemiological data. We linked the Weibull dose–response function and a physiologically based pharmacokinetic (PBPK) model to estimate safe drinking water arsenic concentrations and to perform the risk characterization. We calculated odds ratios (ORs) to assess the relative magnitude of the effect of the arsenic exposure on the likelihood of the prevalence of children skin lesions by calculating proposed Weibull-based prevalence ratios of exposed to control groups associated with the age group-specific PBPK model predicted dimethylarsinite (MMA(III)) levels in urine. Positive relationships between arsenic exposures and cumulative prevalence ratios of skin lesions were found using Weibull dose–response model (r 2 =0.91–0.96). We reported that the safe drinking water arsenic standards were recommended to be 2.2 and 1 μg/L for male and 6 and 2.8 μg/L for female in 0–6 and 7–18 years age groups, respectively, based on hyperpigmentation with an excess risk of 10−3 for a 75 years lifetime exposure. Risk predictions indicate that estimated ORs have 95% confidence intervals of 1.33–5.12, 1.74–19.15, and 2.81–19.27 based on mean drinking water arsenic contents of 283.19, 282.65, and 468.81 μg/L, respectively, in West Bengal, India, Bangladesh, and southwestern Taiwan. Our findings also suggest that increasing urinary monomethylarsonic acid (MMA) levels are associated with an increase in risks of arsenic-induced children skin lesions. [Copyright &y& Elsevier]

Objective: Arsenic is a pervasive contaminant in underground aquifers worldwide, yet documentation of health effects associated with low-to-moderate concentrations (<100μg/L) has been stymied by uncertainties in assessing long-term exposure. A critical component of assessing exposure to arsenic in drinking water is the development of models for predicting arsenic concentrations in private well water in the past; however, these models are seldom validated. The objective of this paper is to validate alternative spatial models of arsenic concentrations in private well water in southeastern Michigan. Methods: From 1993 to 2002, the Michigan Department of Environmental Quality analyzed arsenic concentrations in water from 6050 private wells. This dataset was used to develop several spatial models of arsenic concentrations in well water: proxy wells based on nearest-neighbor relationships, averages across geographic regions, and geostatistically derived estimates based on spatial correlation and geologic factors. Output from these models was validated using arsenic concentrations measured in 371 private wells from 2003 to 2006. Results: The geostatisical model and nearest-neighbor approach outperformed the models based on geographic averages. The geostatistical model produced the highest degree of correlation using continuous data (Pearson''s r=0.61; Spearman''s rank ρ=0.46) while the nearest-neighbor approach produced the strongest correlation (κ weighted=0.58) using an a priori categorization of arsenic concentrations (<5, 5–9.99, 10–19.99, ⩾20μg/L). When the maximum contaminant level was used as a cut-off in a two-category classification (<10, ⩾10μg/L), the nearest-neighbor approach and geostatistical model had similar values for sensitivity (0.62–0.63), specificity (0.80), negative predictive value (0.85), positive predictive value (0.53), and percent agreement (75%). Discussion: This validation study reveals that geostatistical modeling and nearest-neighbor approaches are effective spatial models for predicting arsenic concentrations in private well water. Further validation analyses in other regions are necessary to indicate how widely these findings may be generalized. [Copyright &y& Elsevier]

Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1–1610 μg/L in Cambodia (average 217 μg/L) and 1–845 μg/L in southern Vietnam (average 39 μg/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1–3050 μg/L (average 159 μg/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12–40 m deep cores from the Red River delta contain arsenic levels of 2–33 μg/g (average 7 μg/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to be of natural origin and caused by reductive dissolution of arsenic-bearing iron phases buried in aquifers. The population at risk of chronic arsenic poisoning is estimated to be 10 million in the Red River delta and 0. 5–1 million in the Mekong delta. A subset of hair samples collected in Vietnam and Cambodia from residents drinking groundwater with arsenic levels >50 μg/L have a significantly higher arsenic content than control groups (<50 μg/L). Few cases of arsenic related health problems are recognized in the study areas compared to Bangladesh and West Bengal. This difference probably relates to arsenic contaminated tube-well water only being used substantially over the past 7 to 10 years in Vietnam and Cambodia. Because symptoms of chronic arsenic poisoning usually take more than 10 years to develop, the number of future arsenic related ailments in Cambodia and Vietnam is likely to increase. Early mitigation measures should be a high priority. [Copyright &y& Elsevier]

In the context of arsenic contamination of groundwater in Bangladesh, this paper analyses rural people's preferences for arsenic-free drinking water options. A particular focus is on rural households' willingness to pay for piped water supply which can provide a sustainable solution to the arsenic problem, and how the preference for piped water supply compares with that for various other household/community-based arsenic mitigation technologies. The analysis is based on data collected in a survey of over 2700 households in rural Bangladesh. Six arsenic mitigation technologies were selected for the study: three-kolshi (pitcher) method, activated alumina method (household-based and community-based), dugwell, pond sand filter and deep tubewell (handpump). The survey results indicate that, after taking into consideration the initial and recurring costs, convenience, associated risks and the advantages and disadvantages of each selected technology, the preference of the rural people is overwhelmingly in favor of deep tubewells, followed by the three-kolshi method. The analysis reveals a strong demand for piped water in both arsenic-affected and arsenic-free rural areas, and scope of adequate cost recovery. Between piped water and other arsenic mitigation technologies, the preference of the rural people is found to be predominantly in favor of the former. [ABSTRACT FROM AUTHOR]

Abstract: Access to safe drinking water has been an important national goal in Bangladesh and other developing countries. While Bangladesh has almost achieved accepted bacteriological drinking water standards for water supply, high rates of diarrheal disease morbidity indicate that pathogen transmission continues through water supply chain (and other modes). This paper investigates the association between water quality and selected management practices by users at both the supply and household levels in rural Bangladesh. Two hundred and seventy tube-well water samples and 300 water samples from household storage containers were tested for fecal coliform (FC) concentrations over three surveys (during different seasons). The tube-well water samples were tested for arsenic concentration during the first survey. Overall, the FC was low (the median value ranged from 0 to 4cfu/100ml) in water at the supply point (tube-well water samples) but significantly higher in water samples stored in households. At the supply point, 61% of tube-well water samples met the Bangladesh and WHO standards of FC; however, only 37% of stored water samples met the standards during the first survey. When arsenic contamination was also taken into account, only 52% of the samples met both the minimum microbiological and arsenic content standards of safety. The contamination rate for water samples from covered household storage containers was significantly lower than that of uncovered containers. The rate of water contamination in storage containers was highest during the February–May period. It is shown that safe drinking water was achieved by a combination of a protected and high quality source at the initial point and maintaining quality from the initial supply (source) point through to final consumption. It is recommended that the government and other relevant actors in Bangladesh establish a comprehensive drinking water system that integrates water supply, quality, handling and related educational programs in order to ensure the safety of drinking water supplies. [Copyright &y& Elsevier]

High arsenic concentrations in groundwater were first detected in western Bangladesh in the early 1990s. The arsenic is of natural origin and is believed to be mobilized in the subsurface by a number of mechanisms that are not yet clearly understood. Estimates of the population in Bangladesh now exposed to concentrations over the national drinking water standard vary from 20 million to over 36 million people, with 57 million out of a population of over 140 million being exposed to levels higher than the World Health Organization standard. While a national survey has identified 38,430 chronic cases so far, at least one scientific study estimates that the prevalence of arsenicosis in Bangladesh annually could be up to two million cases if consumption of contaminated water continues. For skin cancer it could be up to one million cases, and the incidence of death from arsenic-induced cancer could be 3,000 cases. In response to the problem, many initiatives have been launched both domestically and internationally to analyze and deal with the situation, including finding alternate sources of water and ways of treating it. By the middle of 2005, 1,851 deep tube wells had been installed to draw from the (so far) arsenic-free deep aquifer, with plans to put in 8,981 more. At the same time, 5,626 dug wells, 458 pond sand filters, and 2,606 household-scale rainwater-harvesting units have been installed, but there are still problems with these systems and other technologies to treat water, and Bangladesh's government is reviewing and certifying technologies that remove arsenic from water. This paper presents an overview of some of the important aspects of arsenic contamination of groundwater in Bangladesh, including an overview of the extent of contamination, current knowledge about the source of arsenic and the mechanisms governing its mobilization, as well as a summary of the present understanding of the impact of irrigating with arsenic-laden water on agricultural soil and the food chain. Several different arsenic removal technologies already in use or tested in Bangladesh are discussed, along with the results of the first phase of a certification process for arsenic removal technologies. [ABSTRACT FROM AUTHOR]

A supply of safe drinking water is a recognized global concern. The arsenic contamination of groundwater in Bangladesh and other countries has furthered this concern. Lack of appropriate water options is one of the main barriers to the supply of safe drinking water for 30-60 million people who are exposed to the risk of drinking arsenic-contaminated water in Bangladesh. This paper describes the experience from a water supply programme for arsenic mitigation based on demand and participation of 30,000 rural people in Srinagar, a subdistrict of Bangladesh. About 85% of the 912 tubewell water samples tested had an arsenic content higher than 0.05 mg/l. The project promoted 11 options including groundwater, surface-water and rainwaterharvesting household-based options as well as community managed technologies. Most people, particularly women, wanted piped water, and hand-operated deep tubewells were also requested. Four cluster-based motorized piped water systems, 20 homebased arsenic-removal options (two types) and an arsenic-removal filter plant were installed. The public contributed about 49, 25 and 20% of the installation costs of piped water, home-based options and filter options, respectively, and 100% of all operation and maintenance costs. The household options and fitter plant were abandoned within a few weeks. Reportedly, those options required too much attention, discharged small volumes of water at tow rates, were difficult to maintain, and discharged poor-quality water. The proportion of families (54%) that drank arsenic-contaminated water during the final survey was significantly tower than in the baseline survey (87%). For arsenic-affected areas, it is recommended that a cluster-based piped water system be given proper consideration when selecting appropriate water options rather than householdbased options or the development of new low-cost options. [ABSTRACT FROM AUTHOR]