Responses of 6500 households to arsenic mitigation in Araihazar, Bangladesh

This study documents the response of 6500 rural households in a 25 km(2) area of Bangladesh to interventions intended to reduce their exposure to arsenic contained in well water. The interventions included public education, posting test results for arsenic on the wells, and installing 50 community wells. Sixty-five percent of respondents from the subset of 3410 unsafe wells changed their source of drinking water, often to new and untested wells. Only 15% of respondents from the subset of safe wells changed their source, indicating that health concerns motivated the changes. The geo-referenced data indicate that distance to the nearest safe well also influenced household responses.     

Water arsenic exposure and children's intellectual function in Araihazar, Bangladesh

Exposure to arsenic has long been known to have neurologic consequences in adults, but to date there are no well-controlled studies in children. We report results of a cross-sectional investigation of intellectual function in 201 children 10 years of age whose parents participate in our ongoing prospective cohort study examining health effects of As exposure in 12,000 residents of Araihazar, Bangladesh. Water As and manganese concentrations of tube wells at each child's home were obtained by surveying all wells in the study region. Children and mothers came to our field clinic, where children received a medical examination in which weight, height, and head circumference were measured. Children's intellectual function on tests drawn from the Wechsler Intelligence Scale for Children, version III, was assessed by summing weighted items across domains to create Verbal, Performance, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and creatinine and were asked to provide blood samples for measuring blood lead and hemoglobin concentrations. Exposure to As from drinking water was associated with reduced intellectual function after adjustment for sociodemographic covariates and water Mn. Water As was associated with reduced intellectual function, in a dose-response manner, such that children with water As levels > 50 microg/L achieved significantly lower Performance and Full-Scale scores than did children with water As levels < 5.5 microg/L. The association was generally stronger for well-water As than for urinary As.     

Water arsenic exposure and intellectual function in 6-year-old children in Araihazar, Bangladesh

BACKGROUND: We recently reported results of a cross-sectional investigation of intellectual function in 10-year-olds in Bangladesh, who had been exposed to arsenic from drinking water in their home wells. OBJECTIVES: We present results of a similar investigation of 301 randomly selected 6-year-olds whose parents participated in our ongoing prospective study of the health effects of As exposure in 12,000 residents of Araihazar, Bangladesh. METHODS: Water As and manganese concentrations of tube wells at each home were obtained by surveying all study region wells. Children and mothers were first visited at home, where the quality of home stimulation was measured, and then seen in our field clinic, where children received a medical examination wherein weight, height, and head circumference were assessed. We assessed children's intellectual function using subtests drawn from the Wechsler Preschool and Primary Scale of Intelligence, version III, by summing weighted items across domains to create Verbal, Performance, Processing Speed, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and were asked to provide blood samples for blood lead measurements. RESULTS: Exposure to As from drinking water was associated with reduced intellectual function before and after adjusting for water Mn, for blood lead levels, and for sociodemographic features known to contribute to intellectual function. With covariate adjustment, water As remained significantly negatively associated with both Performance and Processing Speed raw scores; associations were less strong than in our previously studied 10-year-olds. CONCLUSION: This second cross-sectional study of As exposure expands our concerns about As neurotoxicity to a younger age group.     

砷神经发育毒性及机制研究进展

目的 探讨环氧合酶-2（COX-2）在亚砷酸钠诱导小鼠小胶质细胞活化中的作用及机制。 方法 建立慢性小鼠饮水砷暴露模型,将20只C57BL/6J雄性小鼠随机分为对照组（自来水）和砷暴露组（50 mg/L NaAsO₂）,连续自由饮水暴露12周。Morris水迷宫实验检测小鼠学习记忆能力;苏木精-伊红染色和透射电镜观察海马区神经元病理变化及超微结构改变;免疫荧光检测海马区离子钙结合配适分子-1（IBA-1）表达;蛋白印迹法（WB）检测海马区IBA-1、COX-2、核因子κB p65（NF-κB p65）蛋白表达;酶联免疫吸附法（ELISA）检测海马区白细胞介素-6（IL-6）和肿瘤坏死因子α（TNF-α）表达。 结果 与对照组小鼠[逃避潜伏期（29.01 ± 18.10）s、有效停留距离（11.78 ± 1.25）cm]比较,砷暴露组小鼠逃避潜伏期[（50.79 ± 12.30）s]延长,有效停留距离明显缩短[（9.34 ± 2.34）cm]（P < 0.05）;砷暴露组小鼠海马区出现细胞排列紊乱、水肿、皱缩等病理改变,荧光显微镜下IBA-1绿色荧光表达增多。与对照组[IBA-1（0.75 ± 0.13）、NF-κB p65（0.86 ± 0.14）、COX-2（0.74 ± 0.12）表达水平及IL-6（43.37 ± 1.11）pg/mL、TNF-α（198.46 ± 9.93）pg/mL含量]比较,砷暴露组小鼠海马IBA-1（1.01 ± 0.12）、NF-κBp65（1.23 ± 0.11）、COX-2（1.14 ± 0.13）表达水平及IL-6和TNF-α含量[分别为（93.61 ± 3.18）、（604.00 ± 25.02）pg/mL]明显升高,差异均具有统计学意义（P < 0.05）。 结论 慢性砷暴露导致小鼠学习记忆损伤机制可能与小胶质细胞活化,激活NF-κB上调COX-2分泌促炎性细胞因子,促进神经炎症有关。     

Risk assessment of arsenic mitigation options in Bangladesh

The provision of alternative water sources is the principal arsenic mitigation strategy in Bangladesh, but can lead to risk substitution. A study of arsenic mitigation options was undertaken to assess water quality and sanitary condition and to estimate the burden of disease associated with each technology in disability-adjusted life years (DALYs). Dugwells and pond-sand filters showed heavy microbial contamination in both dry and monsoon seasons, and the estimated burden of disease was high. Rainwater was of good quality in the monsoon but deteriorated in the dry season. Deep tubewells showed microbial contamination in the monsoon but not in the dry season and was the only technology to approach the World Health Organization's reference level of risk of 10-6 DALYs. A few dugwells and one pond-sand filter showed arsenic in excess of 50 microg/L. The findings suggest that deep tubewells and rainwater harvesting provide safer water than dugwells and pond-sand filters and should be the preferred options.     

Rural communities' preferences for arsenic mitigation options in Bangladesh

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.     

Targeting low-arsenic groundwater with mobile-phone technology in Araihazar, Bangladesh

The Bangladesh Arsenic Mitigation and Water Supply Program (BAMWSP) has compiled field-kit measurements of the arsenic content of groundwater for nearly five million wells. By comparing the spatial distribution of arsenic inferred from these field-kit measurements with geo-referenced laboratory data in a portion of Araihazar upazila, it is shown here that the BAMWSP data could be used for targeting safe aquifers for the installation of community wells in many villages of Bangladesh. Recent experiences with mobile-phone technology to access and update the BAMWSP data in the field are also described. It is shown that the technology, without guaranteeing success, could optimize interventions by guiding the choice of the drilling method that is likely to reach a safe aquifer and identifying those villages where exploratory drilling is needed.     

Associations between drinking water and urinary arsenic levels and skin lesions in Bangladesh

The present study examined the associations between drinking water and urinary arsenic levels and skin lesions among 167 residents of three contiguous villages in Bangladesh. Thirty-six (21.6%) had skin lesions (melanosis, hyperkeratosis, or both), of which 13 (36.1%) occurred in subjects who were currently drinking water containing concentrations of arsenic < 50 micrograms/L. The risk for skin lesions in relation to the exposure estimates based on urinary arsenic was elevated more than 3-fold, with the odds ratios for the highest versus the lowest quartiles being 3.6 (95% confidence interval, 1.2 to 12.1) for urinary total arsenic and 3.2 (95% confidence interval, 1.1 to 10.0) for urinary creatinine-adjusted total arsenic. The risks for skin lesions in relation to the exposure estimates based on arsenic in drinking water were less strongly elevated, with the odds ratios for the highest versus the lowest quartiles of exposure being 1.7 (95% confidence interval, 0.6 to 5.1) for drinking-water arsenic and 2.3 for cumulative arsenic index. The study suggests that arsenic exposure is associated with skin lesions in the Bangladesh population and that urinary arsenic may be a stronger predictor of skin lesions than arsenic in drinking water in this population.     

Water manganese exposure and children's intellectual function in Araihazar, Bangladesh

Exposure to manganese via inhalation has long been known to elicit neurotoxicity in adults, but little is known about possible consequences of exposure via drinking water. In this study, we report results of a cross-sectional investigation of intellectual function in 142 10-year-old children in Araihazar, Bangladesh, who had been consuming tube-well water with an average concentration of 793 microg Mn/L and 3 microg arsenic/L. Children and mothers came to our field clinic, where children received a medical examination in which weight, height, and head circumference were measured. Children's intellectual function was assessed on tests drawn from the Wechsler Intelligence Scale for Children, version III, by summing weighted items across domains to create Verbal, Performance, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and creatinine and were asked to provide blood samples for measuring blood lead, As, Mn, and hemoglobin concentrations. After adjustment for sociodemographic covariates, water Mn was associated with reduced Full-Scale, Performance, and Verbal raw scores, in a dose-response fashion; the low level of As in water had no effect. In the United States, roughly 6% of domestic household wells have Mn concentrations that exceed 300 microg Mn/L, the current U.S. Environmental Protection Agency lifetime health advisory level. We conclude that in both Bangladesh and the United States, some children are at risk for Mn-induced neurotoxicity.     

The effect of arsenic mitigation interventions on disease burden in Bangladesh

Many interventions have been advocated to mitigate the impact of arsenic contamination of drinking water in Bangladesh. However, there are few data on the true magnitude of arsenic-related disease in Bangladesh nationally. There has also been little consideration given to possible adverse effects of such interventions, in particular, diarrheal disease. The purpose of this study was to estimate and compare the likely impacts of arsenic mitigation interventions on both arsenic-related disease and water-borne infectious disease. We found that arsenic-related disease currently results in 9,136 deaths per year and 174,174 disability-adjusted life years (DALYs; undiscounted) lost per year in those exposed to arsenic concentrations > 50 microg/L. This constitutes 0.3% of the total disease burden in Bangladesh in terms of undiscounted DALYs. We found intervention to be of overall benefit in reducing disease burden in most scenarios examined, but the concomitant increase in water-related infectious disease significantly reduced the potential benefits gained from intervention. A minimum reduction in arsenic-related DALYs of 77% was necessary before intervention achieved any reduction in net disease burden. This is assuming that interventions were provided to those exposed to > 50 microg/L and would concomitantly result in a 20% increase in water-related infectious disease in those without access to adequate sanitation. Intervention appears to be justified for those populations exposed to high levels of arsenic, but it must be based on exposure levels and on the effectiveness of interventions not only in reducing arsenic but in minimizing risk of water-related infections. Key words: arsenic/adverse effects, Bangladesh, burden of disease, diarrhea, risk assessment, water pollutants, water supply.     

Sustainability of arsenic mitigation in Bangladesh: results of a functionality survey

Arsenic contamination of shallow groundwater in Bangladesh is a major public health problem; the main response to date has been installing alternative water supplies. A survey of the functional status of a statistically representative sample of water supplies was undertaken in 2005 to assess whether these provide a sustainable water supply to arsenic-affected communities. A questionnaire was administered in communities containing a total 1060 water supplies. Eight percent of water supplies could not be located and only 64% of those located were working at the time of the survey. When weighted for the numbers of different technologies across the country, the results indicate 76% of alternative water supplies would be working. Water supplies working at the time of the survey often broke down. Community contributions were found to be important in determining whether a water supply would be functional. Recommendations are made for revisions of the current mitigation strategy.     

Reduction in urinary arsenic with bottled-water intervention

The study was conducted to measure the effectiveness of providing bottled water in reducing arsenic exposure. Urine, tap-water and toenail samples were collected from non-smoking adults residing in Ajo (n=40) and Tucson (n=33), Arizona, USA. The Ajo subjects were provided bottled water for 12 months prior to re-sampling. The mean total arsenic (microg/L) in tap-water was 20.3+/-3.7 in Ajo and 4.0+/-2.3 in Tucson. Baseline urinary total inorganic arsenic (microg/L) was significantly higher among the Ajo subjects (n=40, 29.1+/-20.4) than among the Tucson subjects (n=32, 11.0+/-12.0, p<0.001), as was creatinine-adjusted urinary total inorganic arsenic (microg/g) (35.5+/-25.2 vs 13.2+/-9.3, p<0.001). Baseline concentrations of arsenic (microg/g) in toenails were also higher among the Ajo subjects (0.51+/-0.72) than among the Tucson subjects (0.17+/-0.21) (p<0.001). After the intervention, the mean urinary total inorganic arsenic in Ajo (n=36) dropped by 21%, from 29.4+/-21.1 to 23.2+/-23.2 (p=0.026). The creatinine-adjusted urinary total inorganic arsenic and toenail arsenic levels did not differ significantly with the intervention. Provision of arsenic-free bottled water resulted in a modest reduction in urinary total inorganic arsenic.     

Recommendations for water supply in arsenic mitigation: a case study from Bangladesh

Arsenic problems have been observed in several countries around the world. The challenges of arsenic mitigation are more difficult for developing and poor countries due to resource and other limitations. Bangladesh is experiencing the worst arsenic problem in the world, as about 30 million people are possibly drinking arsenic contaminated water. Lack of knowledge has hampered the mitigation initiatives. This paper presents experience gained during an action research on water supply in arsenic mitigation in rural Singair, Bangladesh. The mitigation has been implemented there through integrated research and development of appropriate water supply options and its use through community participation. Political leaders and women played key roles in the success of the mitigation. More than one option for safe water has been developed and/or identified. The main recommendations include: integration of screening of tubewells and supply of safe water, research on technological and social aspects, community, women and local government participation, education and training of all stakeholders, immediate and appropriate use of the available knowledge, links between intermediate/immediate and long term investment, effective coordination and immediate attention by health, nutrition, agriculture, education, and other programs to this arsenic issue.     

Demand-based water options for arsenic mitigation: an experience from rural Bangladesh

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 rainwater-harvesting 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 home-based 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 filter plant were abandoned within a few weeks. Reportedly, those options required too much attention, discharged small volumes of water at low 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 lower 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 household-based options or the development of new low-cost options.     

Arsenic in tube well water in Bangladesh: health and economic impacts and implications for arsenic mitigation

A national drinking water quality survey conducted in 2009 furnished data that were used to make an updated estimate of chronic arsenic exposure in Bangladesh. About 20 million and 45 million people were found to be exposed to concentrations above the national standard of 50 µg/L and the World Health Organization’s guideline value of 10 µg/L, respectively. From the updated exposure data and all-cause mortality hazard ratios based on local epidemiological studies, it was estimated that arsenic exposures to concentrations > 50 µg/L and 10–50 µg/L account for an annual 24 000 and perhaps as many as 19 000 adult deaths in the country, respectively. Exposure varies widely in the 64 districts; among adults, arsenic-related deaths account for 0–15% of all deaths. An arsenic-related mortality rate of 1 in every 16 adult deaths could represent an economic burden of 13 billion United States dollars (US$) in lost productivity alone over the next 20 years. Arsenic mitigation should follow a two-tiered approach: (i) prioritizing provision of safe water to an estimated 5 million people exposed to > 200 µg/L arsenic, and (ii) building local arsenic testing capacity. The effectiveness of such an approach was demonstrated during the United Nations Children’s Fund 2006–2011 country programme, which provided safe water to arsenic-contaminated areas at a cost of US$ 11 per capita. National scale-up of such an approach would cost a few hundred million US dollars but would improve the health and productivity of the population, especially in future generations.     

砷冶炼工尿中不同价态砷水平初探

应用职业流行病学方法,对2家137名砷冶炼工及42名无砷接触史的人员进行尿中总砷(TAs)和尿中不同价态砷含量分析,初步分析了有色金属冶炼工暴露在不同砷浓度的环境中尿TAs、尿中不同价态砷与年龄、性别、工龄等之间的关系,提示职业砷暴露水平与作业工人尿TAs和尿中二甲基砷酸盐(DMA)含量存在剂量-反应关系。     

Community wells to mitigate the arsenic crisis in Bangladesh

OBJECTIVE: To monitor the effectiveness of deep community wells in reducing exposure to elevated levels of arsenic in groundwater pumped from shallower aquifers. METHODS: Six community wells ranging in depth from 60 m to 140 m were installed in villages where very few of the wells already present produced safe water. By means of flow meters and interviews with villagers carrying water from the community wells, a study was made of the extent to which these were used during one year. The results were compared with household and well data obtained during a previous survey in the same area. FINDINGS: The mean arsenic concentration in water pumped from wells already in use in the villages where the community wells, were installed was 180 +/- 140 micrograms/l (n = 956). Monthly sampling for 4-11 months showed that arsenic levels in groundwater from five of the six newly installed wells were consistently within the WHO guideline value of 10 micrograms/l for drinking-water. One of these wells met the Bangladesh standard of 50 micrograms/l arsenic but failed to meet the WHO guideline values for manganese and uranium in drinking-water. The community wells were very popular. Many women walked hundreds of metres each day to fetch water from them. On average, 2200 litres were hand-pumped daily from each community well, regardless of the season. CONCLUSION: A single community well can meet the needs of some 500 people residing within a radius of 150 m of it in a densely populated village. Properly monitored community wells should become more prominent in campaigns to reduce arsenic exposure in Bangladesh. Between 8000 and 10,000 deep community wells are needed to provide safe water for the four to five million people living in the most severely affected parts of the country.     

Distribution of blood lead, blood cadmium, urinary cadmium, and urinary arsenic levels in employees of a copper smelter

A cross-sectional medical examination of a copper smelter work force included determination of blood lead (Pb-B), zinc protoporphyrin (ZPP), blood cadmium (Cd-B), urinary cadmium (Cd-U), and urinary arsenic (As-U), since it was known that such metal impurities were present in the copper concentrate. A total of 776 copper smelter employees (680 active and 96 retirees and ex-employees) were examined. Another 144 men, never employed in the smelter, but who had worked in copper mines (and sometimes in gold mines) were also examined. Mean Pb-B, ZPP, Cd-B, and As-U were significantly higher in active copper smelter employees than in retirees or miners, indicating exposure and absorption in the copper smelter. Significant correlations between Pb-B and Cd-B, and Cd-U and As-U were present, confirming the common source of absorption. Although there was evidence for an increased lead absorption, this was very moderate, with practically no Pb-B levels in excess of 60 micrograms/dl. A marked effect of smoking on blood cadmium levels was present; nevertheless, for all smoking categories Cd-B levels were significantly higher in active employees, indicating the independent contribution of exposure to cadmium in the smelter. Cd-U did not exceed 10 micrograms/g creatinine, the generally accepted "critical" level for the kidney, but was higher than 2 micrograms/g creatinine, a level very rarely exceeded in the general population, in a sizable proportion of those examined. The highest Cd-U levels were found in retired copper smelter employees; age might have been a contributing factor, besides a longer duration of exposure in the smelter.