Assessment of distillate water quality parameters produced by solar still for potable usage

In this study, a few field experiments were conducted on a simple solar still and water quality analyses were done in laboratory to check the contaminants removal efficiency from raw water samples. A few water quality parameters such as pH, redox, electrical conductivity (EC), salinity, total dissolved solids (TDS), Escherichia coli and arsenic for the feed (before distillation) and product water (after distillation by a solar still) were obtained. A wide range of water samples (e.g. seawater, pond water, and arsenic contaminated groundwater) were collected from various locations in Malaysia and Bangladesh. A few synthetic saline water samples (e.g. 1, 2, 3 and 5% salt) were also prepared. The values of pH (6.5-7.5), redox (100-200 mV), EC (< 750 mS/cm) of the product water were found within the standard ranges. The average removal efficiencies of more than 24 and 99% were obtained from repetitive tests run on salinity and arsenic, respectively. The still was also successful in removing pathogenic bacteria by more than 80%. These obtained parameters of the product water were then compared with various drinking water standards and found that most of the values obtained were within the acceptable ranges provided by the standards. Finally, it is concluded that the solar still is able to produce potable water and can be installed to remove the water scarcity in coastal and arid regions

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

A 30-day follow-up study on the prevalence of SARS-COV-2 genetic markers in wastewater from the residence of COVID-19 patient and comparison with clinical positivity

Wastewater based epidemiology (WBE) is an important tool to fight against COVID-19 as it provides insights into the health status of the targeted population from a small single house to a large municipality in a cost-effective, rapid, and non-invasive way. The implementation of wastewater based surveillance (WBS) could reduce the burden on the public health system, management of pandemics, help to make informed decisions, and protect public health. In this study, a house with COVID-19 patients was targeted for monitoring the prevalence of SARS-CoV-2 genetic markers in wastewa-ter samples (WS) with clinical specimens (CS) for a period of 30 days. RT-qPCR technique was employed to target non-structural (ORF1ab) and structural-nucleocapsid (N) protein genes of SARS-CoV-2, according to a validated experimental protocol. Physiological, environmental, and biological parameters were also measured following the American Public Health Association (APHA) standard protocols. SARS-CoV-2 viral shedding in wastewater peaked when the highest number of COVID-19 cases were clinically diagnosed. Throughout the study period, 7450 to 23,000 gene copies/1000 mL were detected, where we identified 47 % (57/120) positive samples from WS and 35 % (128/360) from CS. When the COVID-19 patient number was the lowest (2), the highest CT value (39.4; i.e., lowest copy number) was identified from WS. On the other hand, when the COVID-19 patients were the highest (6), the lowest CT value (25.2 i.e., highest copy numbers) was obtained from WS. An advance signal of increased SARS-CoV-2 viral load from the COVID-19 patient was found in WS earlier than in the CS. Using customized primer sets in a traditional PCR approach, we confirmed that all SARS-CoV-2 variants identified in both CS and WS were Delta variants (B.1.617.2). To our knowledge, this is the first follow-up study to determine a temporal relationship be-tween COVID-19 patients and their discharge of SARS-CoV-2 RNA genetic markers in wastewater from a single house including all family members for clinical sampling from a developing country (Bangladesh), where a proper sewage system is lacking. The salient findings of the study indicate that monitoring the genetic markers of the SARS-CoV-2 virus in wastewater could identify COVID-19 cases, which reduces the burden on the public health system during COVID-19 pandemics.Peer reviewe

Wastewater-based epidemiological surveillance to monitor the prevalence of SARS-CoV-2 in developing countries with onsite sanitation facilities

Wastewater-based epidemiology (WBE) has emerged as a valuable approach for forecasting disease outbreaks in developed countries with a centralized sewage infrastructure. On the other hand, due to the absence of well-defined and systematic sewage networks, WBE is challenging to implement in developing countries like Bangladesh where most people live in rural areas. Identification of appropriate locations for rural Hotspot Based Sampling (HBS) and urban Drain Based Sampling (DBS) are critical to enable WBE based monitoring system. We investigated the best sampling locations from both urban and rural areas in Bangladesh after evaluating the sanitation infrastructure for forecasting COVID-19 prevalence. A total of 168 wastewater samples were collected from 14 districts of Bangladesh during each of the two peak pandemic seasons. RT-qPCR commercial kits were used to target ORF1ab and N genes. The presence of SARS-CoV-2 genetic materials was found in 98% (165/168) and 95% (160/168) wastewater samples in the first and second round sampling, respectively. Although wastewater effluents from both the marketplace and isolation center drains were found with the highest amount of genetic materials according to the mixed model, quantifiable SARS-CoV-2 RNAs were also identified in the other four sampling sites. Hence, wastewater samples of the marketplace in rural areas and isolation centers in urban areas can be considered the appropriate sampling sites to detect contagion hotspots. This is the first complete study to detect SARS-CoV-2 genetic components in wastewater samples collected from rural and urban areas for monitoring the COVID-19 pandemic. The results based on the study revealed a correlation between viral copy numbers in wastewater samples and SARS-CoV-2 positive cases reported by the Directorate General of Health Services (DGHS) as part of the national surveillance program for COVID-19 prevention. The findings of this study will help in setting strategies and guidelines for the selection of appropriate sampling sites, which will facilitate in development of comprehensive wastewater-based epidemiological systems for surveillance of rural and urban areas of low-income countries with inadequate sewage infrastructure.This research was supported by Water Aid Bangladesh, North South University, Dhaka, COVID-19 Diagnostic Lab, Department of Microbiology, Noakhali Science and Technology University (NSTU), Noakhali, Bangladesh, the International Training Network of Bangladesh University of Engineering and Technology (ITN-BUET) - Centre for Water Supply and Waste Management, and KTH Royal Institute of Technology, Sweden. We acknowledge the sincere help and support of the staff and volunteers of NSTU-COVID-19 Diagnostic Lab, Noakhali Science and Technology University, Bangladesh during the different phases of the study. PB and MTI acknowledge the Life Science Technology Platform, Science for Life Laboratory for the seed funding to initiate the wastewater-based epidemiological studies for SARS-CoV-2 in Bangladesh. We would also like to acknowledge the two anonymous reviewers for their critical comments as well as their thoughtful insights, which has significantly improved the manuscript.Peer reviewe

Arsenic in tubewell water of Bangladesh and approaches for sustainable mitigation

There is an urgent need for Bangladesh to identify the arsenic (As) contaminated tubewells (TWs) in order to assess the health risks and initiate appropriate mitigation measures. This involves testing water in millions of TWs and raising community awareness about the health problems related to chronic As exposure from drinking water, and providing alternative safe water option for the exposed population of the country. The use of spatial maps in a participatory context emerged as an important tool for an effective and rational distribution of alternative safe water options for the exposed population of the country. Field test kit offers the only practical tool available to screen all the TW water considering the time frame and financial resources of the country. A comparison of the field test kit results and laboratory measurements by atomic absorption spectrometry (AAS) as “gold standard” for As in water of 12,532 TWs in Matlab upazila (sub-district) in Bangladesh, indicates that the field test kit correctly determined the status of 87% of the As levels compared to the Bangladesh Drinking Water Standard (BDWS) of 50 μg/L, and 91% of the World Health Organization (WHO) drinking water guideline value of 10 μg/L. In order to identify the sustainable alternative safe water options, different type of safe water options were distributed in Sonargaon and Jhikargachha upazilas (sub-district) in 2001 and later revisited the options in 2004 to identify the sustainable ones. It was observed that community acceptability of the distributed options was not encouraging; less than 2% of the provided options were found to be in use. However, two new approaches emerged from people’s initiatives, which were making rapid and positive contributions to safe water coverage: switching to the existing As-safe TWs and reinstalling TWs at 50-100 m depths by looking at particular type of sediment colours. A study was conducted in Matlab upazila to validate the concept of installation/reinstallation of TWs at certain depths, a new concept promoted by local drillers (masons). The study revealed that locally a thick layer of black to grey sediments overlies an oxidized unit of yellowish-grey to reddish-brown sediments. The correlation between the colour of both units and the groundwater redox conditions was investigated to provide an easy tool for targeting low-arsenic groundwater. The water abstracted from black sediments contained high amount of As concentration but the concentration decreased towards the yeallowish to red sediments. Three boreholes verified the driller's perception of the subsurface lithologic conditions. Discrepancies between the driller's and the research team description of the sediment colours were insignificant. This study shows that sediment colour is a reliable indicator of high and low As-concentrations in TW water and can be used by local drillers to install TW. Lack of financial resources and identification of an appropriate distribution tools are some of the major obstacles to provide sustainable solution to the exposed population of the country. Spatial mapping exercise along with community participation can help maximize the safe water coverage of different alternative safe water options by reducing financial involvement. Combining people’s voice with that of spatial information gave better results and the method is already been proved useful in targeting non-served areas. Participatory Rural Appraisal (PRA) methods along with geographical information system (GIS) used in the study to obtain relevant information. Participants from different focus groups were asked to determine their ‘own priorities’ for spatial planning of alternative arsenic-safe water options. The study discusses community perspectives on demand-based safe water options and reveals the suitability of using participatory geographic information system (PGIS) technique to target non-served areas for rational distribution of safe water options.QC 2010071

Arsenic in tubewell water of Bangladesh and approaches for sustainable mitigation

There is an urgent need for Bangladesh to identify the arsenic (As) contaminated tubewells (TWs) in order to assess the health risks and initiate appropriate mitigation measures. This involves testing water in millions of TWs and raising community awareness about the health problems related to chronic As exposure from drinking water, and providing alternative safe water option for the exposed population of the country. The use of spatial maps in a participatory context emerged as an important tool for an effective and rational distribution of alternative safe water options for the exposed population of the country. Field test kit offers the only practical tool available to screen all the TW water considering the time frame and financial resources of the country. A comparison of the field test kit results and laboratory measurements by atomic absorption spectrometry (AAS) as “gold standard” for As in water of 12,532 TWs in Matlab upazila (sub-district) in Bangladesh, indicates that the field test kit correctly determined the status of 87% of the As levels compared to the Bangladesh Drinking Water Standard (BDWS) of 50 μg/L, and 91% of the World Health Organization (WHO) drinking water guideline value of 10 μg/L. In order to identify the sustainable alternative safe water options, different type of safe water options were distributed in Sonargaon and Jhikargachha upazilas (sub-district) in 2001 and later revisited the options in 2004 to identify the sustainable ones. It was observed that community acceptability of the distributed options was not encouraging; less than 2% of the provided options were found to be in use. However, two new approaches emerged from people’s initiatives, which were making rapid and positive contributions to safe water coverage: switching to the existing As-safe TWs and reinstalling TWs at 50-100 m depths by looking at particular type of sediment colours. A study was conducted in Matlab upazila to validate the concept of installation/reinstallation of TWs at certain depths, a new concept promoted by local drillers (masons). The study revealed that locally a thick layer of black to grey sediments overlies an oxidized unit of yellowish-grey to reddish-brown sediments. The correlation between the colour of both units and the groundwater redox conditions was investigated to provide an easy tool for targeting low-arsenic groundwater. The water abstracted from black sediments contained high amount of As concentration but the concentration decreased towards the yeallowish to red sediments. Three boreholes verified the driller's perception of the subsurface lithologic conditions. Discrepancies between the driller's and the research team description of the sediment colours were insignificant. This study shows that sediment colour is a reliable indicator of high and low As-concentrations in TW water and can be used by local drillers to install TW. Lack of financial resources and identification of an appropriate distribution tools are some of the major obstacles to provide sustainable solution to the exposed population of the country. Spatial mapping exercise along with community participation can help maximize the safe water coverage of different alternative safe water options by reducing financial involvement. Combining people’s voice with that of spatial information gave better results and the method is already been proved useful in targeting non-served areas. Participatory Rural Appraisal (PRA) methods along with geographical information system (GIS) used in the study to obtain relevant information. Participants from different focus groups were asked to determine their ‘own priorities’ for spatial planning of alternative arsenic-safe water options. The study discusses community perspectives on demand-based safe water options and reveals the suitability of using participatory geographic information system (PGIS) technique to target non-served areas for rational distribution of safe water options.QC 2010071

Prospect of phytoaccumulation of arsenic by Brassica juncea (L.) in Bangladesh

The phytoaccummulation of arsenic by Brassica juncea (L.) was investigated for varying concentrations selected within the range that is evident in Bangladeshi soil. B. juncea (Rai and BARI-11) was grown in the hydroponic media under greenhouse condition with different concentrations (0.5, 1.0, 15, 30, 50 and 100 ppm) of sodium arsenite. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to analyze the data. Mapping of potential area of phytoaccumulation of arsenic by B. juncea was done using Geographic information system (GIS). Arsenic was detected at lower concentrations (0.5 and 1.0 ppm) only at root system of the plant. For higher concentrations (15, 30, and 50 ppm) arsenic was detected both in the root and shoot systems. The results suggested that at 15 and 50 ppm uptake was higher compared to 30 ppm. For 100 ppm of arsenic no plant growth was observed. In Bangladesh, where concentration of arsenic is at lower level and present only at rooting zone, B. juncea may be used for phytoaccumulation of arsenic keeping usual agronomic practices. However, for higher concentrations, B. juncea can be regarded as a good accumulator of arsenic where uptake of arsenic was up to 1% of total biomass of the plant.</p

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

Screening of arsenic in tubewell water with field test kits: evaluation of the method from public health perspective.

There is an urgent need for Bangladesh to identify the arsenic (As) contaminated tubewells (TWs) in order to assess the health risks and initiate appropriate mitigation measures. This will involve testing water in millions of TWs and raising community awareness about the health problems related to chronic As exposure from drinking water. Field test kits offer the only practical tool within the time frame and financial resources available for screening and assessment of the As contaminated TWs as well as their monitoring than that of the laboratory measurement. A comparison of field test kit and laboratory measurements by AAS as "gold standard" for As in water of 12,532 TWs in Matlab Upazila in Bangladesh, indicates that the field kit correctly determined the status of 91% of the As levels compared to the Bangladesh Drinking Water Standard (BDWS) of 50 microg/L, and 87% of the WHO guideline value of 10 microg/L. Nevertheless, due to analytical and human errors during the determination of As by the field test kits, some misclassification of wells is inevitable. Cross-checking of the field test kit results, both by Field Supervisor and by the laboratory analyses reveal considerable discrepancies in the correct screening mainly at As concentration ranges of 10-24.9 microg/L and 50-99.9 microg/L, critical from a public health point of view. The uncertainties of misclassification of these two groups of TWs have severe public health implications due to As exposure from drinking water sources. This can be reduced through proper training of the field personnel, cross verification of the field test kit results with laboratory analyses and further development of the field test kits to determine As at low concentrations

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 using 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