The removal of arsenic from water using natural iron oxide minerals, Journal of Cleaner Production, Volumes 29–30, July 2012, Pages 208–213
Sonia Aredes, Bern Klein, , Marek Pawlik. Norman B. Keevil Institute of Mining Engineering, University of British Columbia, 517-6350 Stores Road, Vancouver BC V6T 1Z4, Canada
The contamination of groundwater with arsenic is a serious health issue in many parts of the world. Although iron has been shown to be effective at removal of arsenic from water, there has been no research to assess the feasibility of using natural iron oxide minerals for water treatment. The successful treatment of water to remove arsenic requires an understanding of arsenic chemistry and the physical–chemical interactions between arsenic and iron oxide minerals. A study was conducted to evaluate hematite, magnetite, goethite and iron rich laterite soil as arsenic adsorbents. Electroacoustic measurements were conducted to assess the nature of arsenic adsorption. Results showed that arsenic adsorption occurred over the entire pH range tested (pH 4–11). The isoelectric point shifted due to arsenic adsorption and this is a strong evidence of specific ion adsorption. This was supported by leaching tests that indicated strong attachment of arsenic to the surface of iron oxide minerals. Adsorption tests showed that iron rich laterite was most effective for arsenic removal, followed by goethite, magnetite and hematite. This was attributed to the higher specific surface area of the respective minerals.
The study also demonstrates a simple water treatment method involving the use of low cost natural iron oxide minerals for arsenic removal to meet drinking water standards. Treatment of 100 mL of water containing 20 ppm arsenic with 5 g of laterite reduced the arsenic level down to 10 ppb within a period of 10 min.
Am J Trop Med Hyg. 2012 Feb;86(2):280-91.
Prediction of child health by household density and asset-based indices in impoverished indigenous villages in rural Panamá.
Halpenny CM, Koski KG, Valdés VE, Scott ME. Institute of Parasitology and McGill School of Environment Macdonald Campus of McGill University, Ste-Anne de Bellevue, Quebec, Canada.
Email: carli.halpenny@mail.mcgill.ca
Chronic infection over a 16-month period and stunting of preschool children were compared between more spatially dense versus dispersed households in rural Panamá. Chronic protozoan infection was associated with higher household density, lower household wealth index, poor household water quality, yard defecation, and the practice of not washing hands with soap before eating.
Models for chronic diarrhea confirmed the importance of household wealth, water quality, sanitation, and hygiene practices. Furthermore, chronic protozoan infection was an important predictor for low height-for-age, along with low household wealth index scores, but not household density. Thus, despite better access to health related infrastructure in the more densely populated households, chronic protozoan infection was more common, and was associated with higher rates of child stunting, compared with more dispersed households.
Issue 52 April 20>, 2012 | Focus on Small-Scale WASH Service Providers
This issue of the Weekly contains resources on small-scale providers of WASH services. It is only in recent years that partnerships with small operators have begun to receive serious attention from researchers, planners and policymakers. Several of the reports below conclude that small-scale providers can deliver dynamic and responsive services to communities. One UNDP report, however, argues that small-scale providers in Kenya are predators who charge high prices and supply poor quality water. The resources below include overviews, country studies from Benin, Cambodia, Kenya, Nigeria, Philippines and Tanzania, and videos.
Please let WASHplus know at any time if you have resources to share for future issues of WASHplus Weekly or if you have suggestions for future topics. An archive of past Weekly issues is available on the WASHplus website.
American Journal of Tropical Medicine and Hygiene, April 2012
Using Limes and Synthetic Psoralens to Enhance Solar Disinfection of Water (SODIS): A Laboratory Evaluation with Norovirus, Escherichia coli, and MS2
Alexander S. Harding and Kellogg J. Schwab
E-mail: kschwab@jhsph.edu
We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV).
Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Slurry and 5.6 logs by SODIS + Lime Juice in 30-minute solar exposures, compared with a 1.5 log reduction with SODIS alone (N = 3; P < 0.001). MS2 was inactivated > 3.9 logs by SODIS + Lime Slurry, 1.9 logs by SODIS + Lime Juice, and 1.4 logs by SODIS in 2.5-hour solar exposures (N = 3; P < 0.05).
MNV was resistant to SODIS, with < 2 log reductions after 6 hours. Efficacy of SODIS against human norovirus should be investigated further.
UN-Water Global Analysis and Assessment of Sanitation and Drinking-Water: The Challenge of Extending and Sustaining Services, 2012. GLASS 2012 Report.
WHO; UN Water.
This second UN-Water GlAAS report presents data received from 74 developing countries, covering all the Millennium Development Goal (MDG) regions, and from 24 external support agencies (eSAs), representing approximately 90% of official development assistance (oDA) for sanitation and drinking-water.
Key Messages
- Central government continues to be a major source of funding for water and sanitation, although many low- and middle-income countries remain dependent on external aid. external funding for WASh amounted to more than 1% of GDP in seven developing countries.
- Existing levels of household and private investment are poorly understood, but available data suggest that they are significant sources of financing and can make major contributions to supporting operation and maintenance of services.
- The majority of countries report that sector information systems for financial planning and reporting are inadequate.
- Data suggest that funds spent on operation and maintenance are insufficient. A majority of countries indicate that rural water supply programmes are not effective due to lack of funding, whereas one third of countries report that urban utilities lack revenue to fund operation and maintenance.
- Funding levels for WASh are reported to remain insufficient, especially for sanitation. Drinking-water continues to absorb the majority of WASh funding, even in countries with a relatively high drinking-water supply coverage and relatively low sanitation coverage.
- Most countries could not report how much they spend on hygiene, and for those that did, it was only about 2% of WASh expenditure.
- The breakdown of expenditure for WASh in rural and urban areas appears only weakly correlated with needs.
- Long procurement processes and heavy administrative burdens mean that many countries struggle to efficiently disburse the limited funds that are committed. Absorption of domestic capital commitments is higher than that of donor commitments, but appears to be declining. To strengthen the collection of WASh financial information, a harmonized method of data monitoring is needed (one such method is proposed in Annex B).
Environmental Science and Technology, Volume 46, Issue 5, 6 March 2012, Pages 2501-2507
Risk of gastrointestinal illness associated with the consumption of rainwater: A systematic review
Dean, J., Hunter, P.R. Norwich School of Medicine, University of East Anglia, Norwich, United Kingdom
The collection of rainwater for human consumption is a practice well established in many parts of the world. Much of the research to date regarding this inexpensive and sustainable source has focused on its microbiological or chemical quality and there have been no reviews of epidemiological evidence regarding actual health risks associated with rainwater consumption.
Electronic bibliographic databases were searched for epidemiological studies that attempted to quantify the risk of gastrointestinal disease linked to the consumption of harvested rainwater. Online databases were searched from the oldest date up to January 2011. Both observational and experimental studies were included. In addition, reference sections of key articles were searched and authors of previous studies were contacted where appropriate.
Studies were assessed for relevance independently and in duplicate. Searches returned a total of 764 articles, 13 met inclusion criteria, 5 of these were outbreak reports, and 9 were studies of other design types. Pooled subgroup analysis suggests that rainwater is associated with reduced risk of illness compared to unimproved supplies (relative risk 0.57 95% CI 0.42, 0.77). There was no significant difference in risk in the pooled analysis of studies that compared rainwater to improved water supplies (relative risk 0.82 95% CI 0.38, 1.73).
However, there was heterogeneity with one study showing an excess risk of campylobacteriosis. Classification of outbreak reports determined that 4 reports were “strongly associated with rainwater” while 1 report was “probably associated with rainwater”. We conclude that the evidence suggests that rainwater is safer than water from unimproved water supplies. Where feasible rainwater harvesting should be encouraged as a step toward achieving millennium development targets.
Environ Sci Technol. 2012 Apr 9.
Linking quantitative microbial risk assessment and epidemiological data: Informing safe drinking water trials in developing countries.
Enger K, Nelson KL, Clasen T, Rose JB, Eisenberg JN.
Intervention trials are used extensively to assess household water treatment (HWT) device efficacy against diarrheal disease in developing countries. Using these data in policy, however, requires addressing issues of generalizability (relevance of one trial in other contexts) and systematic bias associated with design and conduct of a study. To illustrate how quantitative microbial risk assessment (QMRA) can address water safety and health issues, we analyzed a published randomized controlled trial (RCT) of the LifeStraw® Family Filter in the Congo.
The model accounted for bias due to 1) incomplete compliance with filtration, 2) unexpected antimicrobial activity by the placebo device, and 3) incomplete recall of diarrheal disease. Effectiveness was measured using the longitudinal prevalence ratio (LPR) of reported diarrhea. The Congo RCT observed an LPR of 0.84 (95% CI: 0.61, 1.14). Our model predicted LPRs, assuming a perfect placebo, ranging from 0.50 (2.5-97.5 percentile: 0.33, 0.77) to 0.86 (2.5-97.5 percentile: 0.68, 1.09) for high (but not perfect) and low (but not zero) compliance, respectively.
The calibration step provided estimates of the concentrations of three pathogen types (modeled as pathogenic E. coli, Giardia, and rotavirus) in drinking water consistent with the longitudinal prevalence of reported diarrhea measured in the trial constrained by epidemiological data from the trial. Use of a QMRA model demonstrated the importance of compliance in HWT efficacy, the need for pathogen data from source waters, the effect of quantifying biases associated with epidemiological data, and the usefulness of generalizing the effectiveness of HWT trial to other contexts.
AIDSTAR-One – SMALL DOABLE ACTIONS FOR WATER, SANITATION, AND HYGIENE -
EXCERPT FROM IMPROVING THE LIVES OF PEOPLE LIVING WITH HIV (PLHIV) THROUGH WASH: WATER, SANITATION, AND HYGIENE PARTICIPANT TECHNICAL RESOURCE GUIDE
Journal of Water and Health In Press, March 2012
A post-implementation evaluation of ceramic water filters distributed to tsunami-affected communities in Sri Lanka
Lisa M. Casanova, Adam Walters, Ajith Naghawatte and Mark D. Sobsey
Institute of Public Health, Georgia State University, P.O. Box 3995, Atlanta GA 30302, USA E-mail: lcasanova@gsu.edu
Medecins Sans Frontieres
Department of Microbiology, Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina Chapel Hill, USA
Sri Lanka was devastated by the 2004 Indian Ocean tsunami. During recovery, the Red Cross distributed approximately 12,000 free ceramic water filters. This cross-sectional study was an independent post-implementation assessment of 452 households that received filters, to determine the proportion still using filters, household characteristics associated with use, and quality of household drinking water. The proportion of continued users was high (76%). The most common household water sources were taps or shallow wells. The majority (82%) of users used filtered water for drinking only. Mean filter flow rate was 1.12 L/hr (0.80 L/hr for households with taps and 0.71 for those with wells).
Water quality varied by source; households using tap water had source water of high microbial quality. Filters improved water quality, reducing Escherichia coli for households (largely well users) with high levels in their source water. Households were satisfied with filters and are potentially long-term users. To promote sustained use, recovery filter distribution efforts should try to identify households at greatest long-term risk, particularly those who have not moved to safer water sources during recovery. They should be joined with long-term commitment to building supply chains and local production capacity to ensure safe water access.
Research Journal of Applied Sciences, Engineering and Technology 4(9): 1094-1098, 2012
Quality of Sachet Water and Bottled Water in Bolgatanga Municipality of Ghana
Emmanuel O. Oyelude and Solomon Ahenkorah
This study assessed the physicochemical and bacteriological characteristics of sachet and bottled water brands on sale in Bolgatanga municipality, Ghana. Turbidity, colour, total dissolved solids, total hardness, calcium ion, magnesium ion, total iron, chloride ion, nitrate ion, phosphate ion and sulphate ion of all samples were within the WHO drinking-water guideline. About fifty percent of the water samples had fluoride ion level ranging from 0.15-0.45 mg/L. These values are below the WHO recommended minimum limit of 0.5 mg/L. Sachet water samples generally possessed good physicochemical characteristics.
However, three out of every four sachet water samples were contaminated by coliform bacteria ranging from 12-168 cfu/100 mL. Faecal coliform bacteria ranging from 2-63 cfu/100 mL were detected in more than 60% of the sachet water brands. All the unbranded hand-filled hand-tied sachet water samples without exception were contaminated by faecal coliform bacteria. This is contrary to the recommendation by WHO that faecal coliform bacteria must not be detectable in a 100-mL sample of drinking water. Although two percent of the bottled water samples had pH levels below the minimum level of 6.5 recommended by WHO, the samples generally possessed good physicochemical and bacteriological characteristics.
On the average, bottled water samples were of good quality and the sachet water samples were of variable quality. This was probably due to the problem of poor sanitation in Bolgatanga municipality and the fact that sachet water brands are not always produced under scrutinised hygienic conditions.
