Anoxic storage to promote arsenic removal with groundwater-native iron.

Storage containers are usually used to provide a constant water head in decentralized, community groundwater treatment systems for the removal of iron (Fe) and arsenic (As). However, the commonly practiced aeration prior to storage assists in rapid and complete Fe2+ oxidation, resulting in poor As removal, despite sufficient native-Fe2+ in the source water. In this study, it was found that application of anoxic storage enhanced As removal from groundwater, containing ≥300 µg/L of As(III) and 2.33 mg/L of Fe2+ in an As affected village of Rajshahi district in Bangladesh. Although the oxidation of Fe2+ and As(III) during oxic storage was considerably faster, the As/Fe removal ratio was higher during anoxic storage (61-80±5 µgAs/mgFe) compared to the oxic storage (45±5 µgAs/mgFe). This higher As removal efficacy in anoxic storage containers could not be attributed to the speciation of As, since As(V) concentrations were higher during oxic storage due to more favorable abiotic (As(III) oxidation by O2 and Fenton-like intermediates) and biotic (As(III) oxidizing bacteria, e.g., Sideroxydans, Gallionella, Hydrogenophaga) conditions. The continuous, in-situ hydrous ferric oxide floc formation during flow-through operation, and the favorable lower pH aiding higher sorption capacities for the gradually formed As(V) likely contributed to the improved performance in the anoxic storage containers.

What is cholera? A preliminary study on caretakers' knowledge in Bangladesh.

BACKGROUND: Cholera has afflicted the Indian sub-continent for centuries, predominantly in West Bengal and modern-day Bangladesh. This preliminary study aims to understand the current level of knowledge of cholera in female Bangladeshi caretakers, which is important in the outcome of the disease and its spread. A pilot study was conducted among 85 women in Bangladesh using qualitative questionnaires to explore the ability of female caretakers in identifying cholera and its transmission. FINDINGS: The survey revealed that though all the female caretakers were aware of the term "cholera," nearly a third of the respondents did not associate diarrhea with cholera or mentioned symptoms that could not be caused by cholera (29 %). Approximately half of the respondents associated water with the cause of cholera (56 %) and only 8 % associated cholera with sanitation or hygiene. Shame and stigma (54 %) were more commonly described than death (47 %) as negative effects of cholera. CONCLUSIONS: The results from this study are suggestive of a need for reformulation of cholera and diarrhea communication. Messaging should be based on signs of dehydration, foregoing the use of medical terminology.

Rural drinking water at supply and household levels: quality and management.

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 4 cfu/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.

Coliforms in the water and hemoglobin concentration are predictors of gastrointestinal morbidity of Bangladeshi children ages 1-10 years.

The presence of pathogens in the water and children's poor nutritional status are likely to increase morbidity in developing countries. Understanding the interactions between the environmental and nutritional factors is important from the standpoint of improving child health. In this study, we analyzed the effects of fecal and total coliforms in the water available at the source and that stored in the household on the spells of gastrointestinal morbidity of 99 Bangladeshi children at three time points in an 8-month period. Fecal and total coliforms in the stored water were significant predictors (P < 0.05) of morbidity that was modeled using dynamic random effects models. Moreover, children with better hemoglobin status experienced lower morbidity. An empirical model for the proximate determinants of hemoglobin concentration showed significant negative associations between children's hookworm loads and hemoglobin. While the children's intakes of bioavailable iron, iron from meat, fish, and poultry, and iron from animal sources were not significant predictors of hemoglobin status in this population, the need for broader interventions for improving child health was apparent.