Arsenic Exposure In Bangladesh Research Articles

Halved mortality after reducing arsenic exposure in Bangladesh: a prospective cohort study with more than 20 years of follow-up

Halved mortality after reducing arsenic exposure in Bangladesh: a prospective cohort study with more than 20 years of follow-up

Low-cost informational intervention reduced drinking water arsenic exposure in Bangladesh.

Thirty million Bangladeshis continue to drink water with unacceptable levels of arsenic (>10 μg/L), resulting in a large public health burden. The vast majority of the Bangladeshi population relies on private wells, and less than 12% use piped water, increasing the complexity of mitigation efforts. While mass testing and informational campaigns were successful in the early 2,000 s, they have received little attention in recent years, even though the number of wells in the country has likely more than doubled. We investigated the effect of a low-cost (<USD 10/household) informational intervention on reducing arsenic exposure through a randomized control trial design. The sample size was ∼10% of the study area households, and the intervention provided exposure awareness material, the arsenic concentration of the household's drinking water, and information about alternate water sources nearby with improved water quality. The informational intervention lowered household arsenic exposure (P=0.0002), with an average reduction in arsenic levels of ∼60%. Approximately one third of the study households requested to test an additional water source at no cost. Providing the intervention a second time led to more households changing their water source but did not further reduce exposure (P=0.39). Our study establishes a causal relationship between the informational intervention and the observed reduction in household arsenic exposure. Our findings demonstrate that water testing and recommendations for accessing improved water provide an immediate, effective, and inexpensive means of reducing the public health burden of arsenic exposure in Bangladesh.

Arsenic contamination in groundwater and food chain with mitigation options in Bengal delta with special reference to Bangladesh.

Bangladesh, situated in Bengal delta, is one of the worst affected countries by arsenic contamination in groundwater. Most of the people in the country are dependent on groundwater for domestic and irrigation purposes. Currently, 61 districts out of 64 districts of Bangladesh are affected by arsenic contamination. Drinking arsenic contaminated groundwater is the main pathway of arsenic exposure in the population. Additionally, the use of arsenic-contaminated groundwater for irrigation purpose in crop fields in Bangladesh has elevated arsenic concentration in surface soil and in the plants. In many arsenic-affected countries, including Bangladesh, rice is reported to be one of the significant sources of arsenic contamination. This review discussed scenario of groundwater arsenic contamination and transmission of arsenic through food chain in Bangladesh. The study further highlighted the human health perspectives of arsenic exposure in Bangladesh with possible mitigation and remediation options employed in the country.

Well-Switching to Reduce Arsenic Exposure in Bangladesh: Making the Most of Inaccurate Field Kit Measurements.

Well‐switching programs in Bangladesh have successfully lowered arsenic exposure. In these programs, households switch from wells that are labeled “unsafe” to nearby wells labeled “safe,” but these designations are usually based on inherently inaccurate field kit measurements. Here, we (a) compare the efficacy of field‐kit measurements to accurate laboratory measurements for well switching, (b) investigate the potential impact on well switching of the chosen “safe” threshold, and (c) consider the possible benefits of providing more detailed concentration information than just “safe” and “unsafe.” We explore different hypothetical mitigation scenarios by combining two extensive data sets from Araihazar Bangladesh: a blanket survey of 6595 wells over 25 km2 based on laboratory measurements and 943 paired kit and laboratory measurements from the same area. The results indicate that the decline in average arsenic exposure from relying on kit rather than laboratory data is modest in relation to the logistical and financial challenge of delivering exclusively laboratory data. The analysis further indicates that the 50 μg/L threshold used in Bangladesh to distinguish safe and unsafe wells, rather than the WHO guideline of 10 μg/L, is close to optimal in terms of average exposure reduction. We also show that providing kit data at the maximum possible resolution rather than merely classifying wells as unsafe or safe would be even better. These findings are relevant as the government of Bangladesh is about to launch a new blanket testing campaign of millions of wells using field kits.

Inequitable allocation of deep community wells for reducing arsenic exposure in Bangladesh.

Community wells that extend deeper than most private wells are crucial for reducing exposure to groundwater arsenic (As) in rural Bangladesh. This study evaluates the impact on access to safe drinking water of 915 such intermediate (90-150 m) and deep (>150 m) wells across a 180 km2 area where a total of 48,790 tubewells were tested with field kits in 2012-13. Half the shallow private wells meet the Bangladesh standard of 50 µg/L for As in drinking water, whereas 92% of the intermediate and deep wells meet the more restrictive World Health Organization guideline for As in drinking water of 10 µg/L. As a proxy for water access, distance calculations show that 29% of shallow wells with >50 µg/L As are located within walking distance (100 m) of at least one of the 915 intermediate or deep wells. Similar calculations for a hypothetical more even distribution of deep wells show that 74% of shallow wells with >50 µg/L As could have been located within 100 m of the same number deep wells. These observations and well-usage data suggest that community wells in Araihazar, and probably elsewhere in Bangladesh, were not optimally allocated by the government because of elite capture.

Evaluation of an Elementary School-based Educational Intervention for Reducing Arsenic Exposure in Bangladesh.

BackgroundChronic exposure to well water arsenic (As) remains a major rural health challenge in Bangladesh and some other developing countries. Many mitigation programs have been implemented to reduce As exposure, although evaluation studies for these efforts are rare in the literature.ObjectivesIn this study we estimated associations between a school-based intervention and various outcome measures of As mitigation.MethodsWe recruited 840 children from 14 elementary schools in Araihazar, Bangladesh. Teachers from 7 schools were trained on an As education curriculum, whereas the remaining 7 schools without any training formed the control group. Surveys, knowledge tests, and well-water testing were conducted on 773 children both at baseline and postintervention follow-up. Urine samples were collected from 210 children from 4 intervention schools and the same number of children from 4 control schools. One low-As (< 10 μg/L) community well in each study village was ensured during an 18-month intervention period.ResultsAfter adjustment for the availability of low-As wells and other sociodemographic confounders, children receiving the intervention were five times more likely to switch from high- to low-As wells (p < 0.001). We also observed a significant decline of urinary arsenic (UAs) (p = < 0.001) (estimated β = –214.9; 95% CI: –301.1, –128.7 μg/g creatinine) among the children who were initially drinking from high-As wells (> Bangladesh standard of 50 μg/L) and significantly improved As knowledge attributable to the intervention after controlling for potential confounders.ConclusionsThese findings offer strong evidence that school-based intervention can effectively reduce As exposure in Bangladesh by motivating teachers, children, and parents.CitationKhan K, Ahmed E, Factor-Litvak P, Liu X, Siddique AB, Wasserman GA, Slavkovich V, Levy D, Mey JL, van Geen A, Graziano JH. 2015. Evaluation of an elementary school–based educational intervention for reducing arsenic exposure in Bangladesh. Environ Health Perspect 123:1331–1336; http://dx.doi.org/10.1289/ehp.1409462

Randomized Controlled Trials of Community Based Arsenic Interventions to Reduce Arsenic Exposure in Bangladesh

Background: Millions of villagers in Bangladesh drink water which exceeds the Bangladesh Arsenic (As) standard of 50 micrograms per liter. Exposure to elevated levels of inorganic As is associated with cancers of the skin, bladder, and lung, developmental effects, cardiovascular disease, and skin lesions. As mitigation typically involves testing the well water without providing resources to address health concerns or give advice on mitigation options. We sought to evaluate community level intervention strategies for As mitigation in Bangladesh. Method: We conducted two randomized controlled trials (RCT) in Singair and Shibalaya, Bangladesh. In the first cluster of 1000 households, we evaluated the effectiveness of having community members versus outside representatives disseminate As education and conduct water As testing using urinary As at baseline and follow-up. In the second cluster RCT of 450 households, we evaluated the effectiveness of community and household level As educational interventions on increasing the adoption of a fee-based As testing program. Our primary outcome in this RCT was a household purchasing As test for their primary drinking water source. Results: In the first RCT, we found that overall 53% of respondent using As contaminated wells (&gt;50?g/L), at baseline switched after receiving the intervention. When we stratified by those residing in a village where less than 60% of wells in use were As unsafe, UNICEF cutoff for well switching as a mitigation option, 74% of study households in the community tester villages, and 72% of households in the outside tester villages reported switching to an As safe drinking water source. These results were confirmed by a 30% reduction in urinary As between baseline and follow-up for those who reported switching to safe wells (p&lt;0.0001). In the RCT of the fee-based As testing program, we found that 93% of households that received the community and household level As interventions purchased an As test, in comparison to only 53% in the control group. Finding: These low cost easily to implement community based arsenic educational interventions were effective in reducing arsenic exposure and promoting the use of a fee-based arsenic testing program in communities in rural Bangladesh.

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.

Association Between Type 2 Diabetes and Chronic Arsenic Exposure in Bangladesh

O-31B7-1 Background/Aims: Chronic exposure to inorganic arsenic in drinking water has been associated with type 2 diabetes (T2D). Most research has been ecological in nature and has focused on high levels of arsenic exposure with few studies directly measuring arsenic levels in drinking water as an index of arsenic exposure. The effect of low-to-moderate levels of arsenic exposure on diabetes risk is largely unknown. Aims: To determine the association between chronic arsenic exposure, as measured in drinking well water, and prevalent T2D in a representative sample of Bangladesh residents. Methods: The study is an analytical cross-sectional study of 1004 randomly selected men and women aged >30 years living in Bangladesh who had continuously consumed arsenic-contaminated drinking water for at least 6 months. T2D cases were defined using the new diagnostic criteria (fasting blood glucose >126 mg/dL) from the WHO guideline (WHO 2006), or a self-reported physician diagnosis of T2D. Results: A total of 1004 individuals participated in the study. The prevalence of T2D was 9% (95% CI: 7%–11%). After adjustment for diabetes risk factors, an increased risk of T2D was observed for arsenic exposure over 50 μg/L with those in the highest category having almost double the risk of T2D (OR = 2.1; 95% CI: 1.3–3.2). For most levels of arsenic exposure, the risk estimates are higher with longer exposure; a dose-response pattern was also observed. Conclusion: These findings suggest an association between chronic arsenic exposure through drinking water and T2D. Risks are generally higher with longer duration of arsenic exposure. The risk of T2D is highest among those who were exposed to the highest concentration of arsenic for more than 10 years.

A prospective study of respiratory symptoms associated with chronic arsenic exposure in Bangladesh: findings from the Health Effects of Arsenic Longitudinal Study (HEALS)

Background and aimsA prospective cohort study was conducted to evaluate the effect of arsenic (As) exposure from drinking water on respiratory symptoms using data from the Health Effects of Arsenic...

Risk of arsenic-related skin lesions in Bangladeshi villages at relatively low exposure: a report from Gonoshasthaya Kendra.

Arsenic concentrations in 25% of tube wells in Bangladesh exceed 50 microg/L, a level known to be hazardous. Levels in individual wells vary widely. We gathered data on arsenic exposure levels and skin lesion prevalence to address the lack of knowledge about risks where the average arsenic concentrations was lower. The nongovernmental organization Gonoshasthaya Kendra did three related studies of keratotic skin lesions since 2004: (1) an ecological prevalence survey among 13 705 women aged > 18 in a random sample of 53 villages; (2) a case-control study of 176 cases and age- and village-matched referents; and (3) a prevalence survey of the entire population of 11,670 in two additional villages. We calculated prevalence as a function of average arsenic concentrations as reported in the National Hydrochemical Survey, and measured arsenic concentrations in wells used by subjects in the case-control study. The prevalence of skin lesions was 0.37% in people exposed to arsenic concentrations below 5 microg/L, 0.63% at 6-50 microg/L, and 6.84% at 81 microg/L. In the case-control analysis, relative risk of skin lesions increased threefold at concentrations above 50 microg/L (P < 0.05). Little serious skin disease is likely to occur if the arsenic concentration in drinking water is kept below 50 microg/L, but ensuring this water quality will require systematic surveillance and reliable testing of all wells, which may be impractical. More research is needed on feasible prevention of toxic effects from arsenic exposure in Bangladesh.

Socioeconomic Status and Risk for Arsenic-Related Skin Lesions in Bangladesh

Arsenic contamination of groundwater is a severe public health crisis in Bangladesh, where the population is exposed to arsenic in drinking water through tube wells used for groundwater collection. In this study, we explored the association between socioeconomic status and arsenic toxicity. We used baseline data from 11438 men and women who were recruited into the Health Effects of Arsenic Longitudinal Study (HEALS), a prospective cohort study on the health effects of arsenic exposure in Bangladesh. We conducted analyses with logistic regression and generalized estimating equations. We found a strong dose-response association with all measures of arsenic exposure and skin lesions. We also found that the effect of arsenic was modified by land ownership on a multiplicative scale, with an increased risk among non-land owners associated with well water arsenic (P=.04) and urinary total arsenic concentrations (P=.03). Our study provides insight into potentially modifiable host characteristics and identifies factors that may effectively target susceptible population subgroups for appropriate interventions.

Dietary Arsenic Exposure in Bangladesh

BackgroundMillions of people in Bangladesh are at risk of chronic arsenic toxicity from drinking contaminated groundwater, but little is known about diet as an additional source of As exposure.MethodsWe employed a duplicate diet survey to quantify daily As intake in 47 women residing in Pabna, Bangladesh. All samples were analyzed for total As, and a subset of 35 samples were measured for inorganic arsenic (iAs) using inductively coupled plasma mass spectrometry equipped with a dynamic reaction cell.ResultsMedian daily total As intake was 48 μg As/day [interquartile range (IQR), 33–67) from food and 4 μg As/day (IQR, 2–152) from drinking water. On average, iAs comprised 82% of the total As detected in dietary samples. After adjusting for the estimated inorganic fraction, 34% [95% confidence interval (CI), 21–49%] of all participants exceeded the World Health Organization’s provisional tolerable daily intake (PTDI) of 2.1 μg As/kg-day. Two of the 33 women who used a well with < 50 μg As/L exceeded this recommendation.ConclusionsWhen drinking water concentrations exceeded the Bangladesh drinking water standard of 50 μg As/L, ingested water was the dominant source of exposure. However, as drinking water As concentrations decrease, the relative contribution of dietary As sources becomes more important to ingested dose. The combined intake from both diet and drinking water can cause some individuals to exceed the PTDI in spite of using a tube well that contains < 50 μg As/L.

Association between nutritional status and arsenicosis due to chronic arsenic exposure in Bangladesh

The role of nutritional factors in arsenic metabolism and toxicity is not clear. Provision of certain low protein diets resulted in decreased excretion of DMA and increased tissue retention of arsenic in experimental studies. This paper reports a prevalence comparison study conducted in Bangladesh to assess the nutritional status among the chronic arsenic exposed and unexposed population. 138 exposed individuals diagnosed as arsenicosis patients were selected from three known arsenic endemic villages of Bangladesh and age, sex matched 144 unexposed subjects were randomly selected from three arsenic free villages. The mean arsenic concentration in drinking water for the exposed and unexposed population was 641.15 and 13.5 μg L−1 respectively. Body Mass Index was found to be lower than 18.5, the cut off point for malnutrition, in 57 (41.31%) out of 138 exposed arsenicosis cases and 31 (21.53%) out of 144 unexposed individuals. The crude prevalence ratio (or risk) was 1.92 (95% CI = 1.33 – 2.78) for poor nutritional status among the arsenicosis cases compared to the unexposed population. The findings of this study add to the evidence that poor nutritional status may increase an individual's susceptibility to chronic arsenic toxicity, or alternatively that arsenicosis may contribute to poor nutritional status.

Community wells to mitigate the arsenic crisis in Bangladesh.

To monitor the effectiveness of deep community wells in reducing exposure to elevated levels of arsenic in groundwater pumped from shallower aquifers. 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. 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. 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.