MIT scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water

Man-made ponds may be responsible for widespread arsenic contamination of ground water affecting millions of people in Bangladesh, a new study says [1].

Rebecca Neumann hangs off the end of bamboo scaffolding built at the field site. Assisted by a man hired from a nearby village, she is connecting a tube that will run from the surface water in the rice field up to a higher point on the scaffolding. Photo: Sarah Jane White, MIT

Researchers in MIT’s Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled scientists, world health agencies and the Bangladeshi government for nearly 30 years.

The research suggests that human alteration to the landscape, the construction of villages with ponds, and the adoption of irrigated agriculture are responsible for the current pattern of arsenic concentration underground.

In 2002, a research team led by Charles Harvey, the Doherty Associate Professor of Civil and Environmental Engineering at MIT, had determined that microbial metabolism of organic carbon was mobilizing the arsenic off the soils and sediments, and that crop irrigation was almost certainly playing a role in the process. But the exact sources of the contaminated water have remained elusive, until now.

Around 25m people in the country have been exposed to arsenic through water. Experts have described the situation as the worst mass poisoning of a population in history.

Man-made ponds – often dug with the help of international aid agencies – were originally created to protects villagers from unclean water.

The arsenic enters water supplies from agricultural and industrial waste or from natural deposits in the ground.

Around two million people in Bangladesh suffer from arsenic poisoning. Chronic ingestion of small doses has been linked to cancer of the bladder, kidney, lung or skin, while large doses can kill immediately.

Arsenic contamination of ground water is a global problem and has occurred in other countries such as Argentina, Chile, China, India, Mexico, Taiwan, Thailand and the United States.

But the gravity of the contamination in Bangladesh is unprecedented. Millions of Bangladeshis knowingly poison themselves because there is often no alternative water source. Harvey estimates that the incidence of death from arsenic-induced cancer will rise to approximately 3,000 cases per year if consumption of contaminated water continues.

Scott Fendorf, a professor at Stanford University who studies arsenic content in soils and sediments along the Mekong River in Cambodia, says Harvey’s previous research, published in 2002, “transformed the scientific community’s outlook on the problem.”

The current work, he adds, has two big ramifications: “It shows that human modifications are impacting the arsenic content in the groundwater; and that while the rice cropping system appears to be buffering the arsenic, the ponds excavated to provide fill to build up the villages are having a negative impact on the release of arsenic.”

Harvard scientist and co-author of the study Rebecca Neumann said that arsenic contamination could be avoided by digging deeper drinking water wells below the ponds.

Charles F. Harvey. Photo: MIT

Harvey and a team of environmental scientists and physicians are making plans for a multi-year study that would provide deep wells for two villages in Bangladesh whose inhabitants suffer from arsenic poisoning. There they would combine continual testing of the well water and hydrogeological modeling of the groundwater system with a study of how the clean water effects the villagers’ health, placing special emphasis on the neurological development of children.

“There are all sorts of studies to show how arsenic hurts people. We’re trying to turn it around and show how removal of the arsenic will help them,” says Harvey.

[1] Neuman, R.B. … [et al.] (2009). Anthropogenic influences on groundwater arsenic concentrations in Bangladesh. Nature Geoscience. Published online: 15 November 2009 | doi:10.1038/ngeo685

Source: BBC, 15 Nov 2009 ; ScienceDaily, 15 Nov 2009; MIT, 15 Nov 2009

Gates Foundation awards $10.9 million to study impacts of sanitation on diseases

Researchers at the University of California, Berkeley, have received a five-year, $10.9 million grant from the Bill & Melinda Gates Foundation to evaluate several interventions to combat diarrheal disease in developing countries.

Dr. Jack Colford

Dr. Jack Colford, professor of epidemiology at UC Berkeley’s School of Public Health, will coordinate the project, working with the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) and Innovations for Poverty Action (IPA).

An estimated 2.2 million children under the age of 5 die from diarrheal diseases each year, according to the World Health Organization. Most of these diseases are thought to be preventable with improvements in sanitation, water quality and hygiene.

Due to the high cost of developing and maintaining large infrastructure projects, such as networked water, there is now a movement toward simpler, alternative methods to improve health in rural areas. However, there is almost no evidence that allows direct comparison of the health benefits or cost effectiveness of these simpler interventions, such as improved latrines, household water treatment and hand washing with soap.

The goal of the new project is to determine how sanitation interventions, delivered alone or as part of combined intervention packages, impact child health and well-being. In addition to improved sanitation, the intervention packages will include drinking water improvements and hand washing solutions. The results have the potential to influence how billions of dollars are directed towards long-term improvements in health and economic outcomes for millions of children each year, said Colford.

“Increasingly, foundations, governments, the World Bank and development agencies such as the MCC (Millennium Challenge Corporation) are demanding evidence of effectiveness when awarding development funds,” said Colford. “Right now, it is unknown whether single interventions are as cost effective as combinations of these interventions. This grant will fund the first large-scale, randomized impact evaluation designed to gather rigorous evidence about this question.”

The study will test the impact of these sanitation, water and hygiene interventions using a large-scale, randomized impact evaluation in Bangladesh and Kenya. These two countries are representative of the two regions that account for the majority of the world’s gastrointestinal disease burden: Southeast Asia and sub-Saharan Africa. The researchers expect to enroll a total of 23,000 children in the trials, which will be monitored by several institutional review boards.

Of the $10.9 million, about $7.9 million will be subcontracted out to the two field sites. Dr. Stephen Luby, head of the Programme on Infectious Diseases and Vaccine Sciences with ICDDR,B, and Michael Kremer, Ph.D., a research affiliate with IPA, will lead the trials in Bangladesh and Kenya, respectively. They will be joined by a team of experts from various disciplines, including public health, economics, behavioral change, nutrition, cognitive development and tropical enteropathy.

Source: Linda Anderberg, UC Berkely News, 05 Nov 2009

Water, sanitation and hygiene interventions to combat childhood diarrhoea in developing countries

Water, sanitation and hygiene interventions to combat childhood diarrhoea in developing countries

Hugh Waddington, Birte Snilstveit, Howard White, and Lorna Fewtrell
Corresponding author email: hwaddington [at] 3ieimpact.org
August 2009
Synthetic review 001
International Initiative for Impact Evaluation (3ie).

Full text

Summary

This report is a synthetic review of impact evaluations examining effectiveness of water, sanitation and hygiene (WSH) interventions in reducing childhood diarrhoea.

The review has been conducted to Campbell/Cochrane Collabo ration standards of systematic review, as well as employing mixed methods of data analysis to assess not only which interventions are effective, or not, but why and under what circumstances. The review provides an update of previous reviews conducted in this area, notably Fewtrell and Colford (2004).

A comprehensive search was conducted of published and unpublished materials. Studies were identified for inclusion which employed rigorous impact evaluation techniques, using experimental (randomised assignme nt) and quasi-experimental methods, and which evaluated the impact of water, sanitation and/or hygiene interventions on diarrhoea morbidity among children in low- and middle-income countries. 65 rigorous impact evaluations were identified for quantitative synthesis, covering 71 distinct interventions assessed across 130,000 children in 35 developing countries during the past three decades. Each study was coded for a range of variables relating to type of intervention, effect size and precision, internal validity (relating to evaluation quality) and external validity (relating to context and behavioural mechanisms). Interventions were grouped into five categories: water supply improvements, water quality, sanitation, hygiene and multiple interventions involving a combination of water and sanitation and/or hygiene. Data were collected and synthesised on both quantitative and qualitative information presented in the evaluations.

The results challenge the notion that water quality treatment in the household (at point -of-use) and sanitation ‘software’ (hygiene) interventions are necessarily the most efficacious and sustainable interventions for promoting reduction of diarrhoea.

While point-of-use water quality interventions appear to be highly effective – and indeed, more effective than water supply or source treatment in reducing diarrhoea – much of the evidence is from trials conducted over small populations and short time periods. More evidence is needed on sustainability, as water quality interventions conducted over longer periods tend to show smaller effectiveness, while compliance rates, and therefore impact, appear to fall markedly over time.

Hygiene interventions, particularly provision of soap for hand-washing, are effective in reducing diarrhoea morb idity, and there does not appear to be evidence that compliance falls over time. The analysis suggests that sanitation ‘hardware’ interventions are also highly effective. However, relatively few studies have been conducted in this area to-date and studies are particularly needed that quantify the possible environmental spillovers from sanitation provision.

Evidence on the combined impact of multiple interventions is mixed. Further primary studies employing factorial design – that is, comparing different interventions using multiple treatment arms – are needed for more conclusiveness on whether water and sanitation/hygiene interventions are substitutes or complements in the health production function.

The study highlights the importance of behavioural factors in determining up-take and sustainable adoption of WSH technologies. Insights from diffusion theory suggest that preventive interventions tend to be adopted more slowly as benefits are difficult to observe and users presumably discontinue treatment as they perceive that the costs of using the intervention outweigh the benefits. These problems are more relevant for interventions aiming to reduce disease prevalence which do not have additional benefits, for example time savings. Unfortunately, few impact evaluations addressing sustainability collect data on the reasons for the levels of compliance and acceptance found among beneficiaries. This information is an essential guide to fostering long-term impact.

Survey of Food-hygiene Practices at Home and Childhood Diarrhoea in Hanoi, Viet Nam

Survey of food-hygiene practices at home and childhood diarrhoea in Hanoi, Viet Nam
Jnl Health, Pop & Nutri, Oct. 2009,  P. 602-611
Full-text

Authors: Kumiko Takanashi, Yuko Chonan, Dao To Quyen, Nguyen Cong Khan, Krishna C. Poudel, and Masamine Jimba

1Department of Community and Global Health, Graduate School of Medicine, University of Tokyo, Japan, 2International Life Sciences Institute Japan Center for Health Promotion, Japan, and 3National Institute of Nutrition, Hanoi, Viet Nam

ABSTRACT

A cross-sectional study was conducted to investigate the potential factors of food-hygiene practices of mothers on the prevalence of diarrhoea among their children. Mothers who had children aged 6 months–5 years were recruited in a hamlet in Viet Nam. The food-hygiene practices included hand-washing, method of washing utensils, separation of utensils for raw and cooked food, and the location where foods were prepared for cooking. A face-to-face interview was conducted, and data on 206 mothers were analyzed. The risk of diarrhoea was significantly higher among children whose mothers prepared food for cooking somewhere other than the table (typically on the ground) compared to children whose mothers prepared food on the table (adjusted odds ratio=2.85, 95% confidence interval 1.11-7.28). The results indicate that food-hygiene practices of mothers, such as avoiding preparing food for cooking on the ground, has a potential impact in preventing diarrhoea among children in Viet Nam.

Intermittent slow sand filtration for preventing diarrhoea among children in Kenyan households using unimproved water sources

Intermittent slow sand filtration for preventing diarrhoea among children in Kenyan households using unimproved water sources: randomized controlled trial
doi:10.1111/j.1365-3156.2009.02381.x
Published Online: 4 Sep 2009

Sangya-Sangam K. Tiwari 1 , Wolf-Peter Schmidt 2 , Jeannie Darby 1 , Z. G. Kariuki 3 and Marion W. Jenkins 1
1 Department of Civil and Environmental Engineering, University of California, Davis, CA, USA
2 Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
3 Ministry of Health, Nakuru District, Nakuru, Kenya

Objective Measure effectiveness of intermittent slow sand filtration for reducing child diarrhoea among households using unimproved water sources in rural Kenya.

Methods A randomized controlled trail was conducted among populations meeting a high-risk profile for child diarrhoea from drinking river water in the River Njoro watershed. Intervention households (30) were provided the concrete BioSand Filter and instructed on filter use and maintenance. Control households (29) continued normal practices. Longitudinal monthly monitoring of diarrhoea (seven-day daily prevalence recall) and of influent, effluent, and drinking water quality for fecal coliform was conducted for 6 months.

Results Intervention households had better drinking water quality than control households (fecal coliform geometric mean, 30.0 CFU vs. 89.0 CFU/100 ml, P < 0.001) and reported significantly fewer diarrhoea days (86 days over 626 child-weeks) compared to controls (203 days over 558 child-weeks) among children up to 15 (age-adjusted RR 0.46; 95 % CI = 0.22, 0.96). Greater child diarrhoea reduction due to the intervention (age-adjusted RR 0.23, 95 % CI = 0.10, 0.51) was observed among the sub-group using unimproved water sources all of the time.

Conclusion Intermittent slow sand filtration, a non-commercial technology, produces similar observed effects on child diarrhoea as commercial POU products, adding to the range of effective options for poor populations (chlorination, ceramic filtration, solar disinfection, flocculation/disinfection).

Shower heads can make you ill

New research suggests that many shower heads are teeming with Mycobacterium avium, a bacteria that can cause lung disease. A third of the 50 shower heads checked contained a film coating of “significant levels” of the bacteria inside concluded  a scientists report from The University of Colorado . “If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy,” said lead researcher Norman Pace. (But how many people are facing the shower head when they turn on the water?) Anyway, from the BBC News:
Water spurting from shower heads can distribute bacteria-filled droplets that suspend themselves in the air and can easily be inhaled into the deepest parts of the lungs, say the scientists from the University of Colorado at Boulder…

While it is rarely a problem for most healthy people, those with weakened immune systems, like the elderly, pregnant women or those who are fighting off other diseases, can be susceptible to infection…

Since plastic shower heads appear to “load up” with more bacteria-rich biofilms, metal shower heads may be a good alternative, said Professor Pace.
Source:BoingBoing, http://www.boingboing.net/2009/09/15/many-shower-heads-fi.html, by David Pescovitz, September 15, 2009.
Related news: http://news.bbc.co.uk/2/hi/health/8254206.stm

Quantifying the burden of disease associated with inadequate provision of water and sanitation in selected sub-Saharan refugee camps

Cronin, A.A. … [et al.] (2009). Quantifying the burden of disease associated with inadequate provision of water and sanitation in selected sub-Saharan refugee camps. Journal of water and health ; vol. 7, no. 4 ; p. 557-68. DOI: 10.2166/wh.2009.089

A WHO methodology is used for the first time to estimate the burden of disease directly associated with incomplete water and sanitation provision in refugee camps in sub-Saharan African countries. In refugee camps of seven countries, containing just fewer than 1 million people in 2005, there were 132,000 cases of diarrhoea and over 280,000 reported cases of malaria attributable to incomplete water and sanitation provision. In the period from 2005 to 2007 1,400 deaths were estimated to be directly attributable to incomplete water and sanitation alone in refugee camps in Ethiopia, Kenya and Tanzania. A comparison with national morbidity estimates from WHO shows that although diarrhoea estimates in the camps are often higher, mortality estimates are generally much lower, which may reflect on more ready access to medical aid within refugee camps. Despite the many limitations, these estimates highlight the burden of disease connected to incomplete water and sanitation provision in refugee settings and can assist resource managers to identify camps requiring specific interventions. Additionally the results reinforce the importance of increasing dialogue between the water, sanitation and health sectors and underline the fact that efforts to reduce refugee morbidity would be greatly enhanced by strengthening water and sanitation provision

Contact: Aidan A. Cronin, Public Health and HIV Section, United Nations High Commissioner for Refugees, Switzerland, E-mail: aacronin [at] gmail.com.

Purchase of drinking water is associated with increased child morbidity and mortality among urban slum-dwelling families in Indonesia

Semba, R.D. … [et al.] (2009). Purchase of drinking water is associated with increased child morbidity and mortality among urban slum-dwelling families in Indonesia. International journal of hygiene and environmental health ; vol. 212, no. 4 : p. 387-97. DOI: 10.1016/j.ijheh.2008.09.001

Author abstract: In developing countries, poor families in urban slums often do not receive municipal services including water. The objectives of our study were to characterize families who purchased drinking water and to examine the relation between purchasing drinking water and child morbidity and mortality in urban slums of Indonesia, using data collected between 1999 and 2003. Of 143,126 families, 46.8% purchased inexpensive drinking water from street vendors, 47.4% did not purchase water, i.e., had running or spring/well water within household, and 5.8% purchased more expensive water in the previous 7 days. Families that purchased inexpensive drinking water had less educated parents, a more crowded household, a father who smoked, and lower socioeconomic level compared with the other families. Among children of families that purchased inexpensive drinking water, did not purchase drinking water, or purchased more expensive water, the prevalence was, respectively, for diarrhea in last 7 days (11.2%, 8.1%, 7.7%), underweight (28.9%, 24.1%, 24.1%), stunting (35.6%, 30.5%, 30.5%), wasting (12.0%, 10.5%, 10.9%), family history of infant mortality (8.0%, 5.6%, 5.1%), and of under-five child mortality (10.4%, 7.1%, 6.4%) (all P<0.0001). Use of inexpensive drinking water was associated with under-five child mortality (Odds Ratio [O.R.] 1.32, 95% Confidence Interval [C.I.] 1.20-1.45, P<0.0001) and diarrhea (O.R. 1.43, 95% C.I. 1.29-1.60, P<0.0001) in multivariate logistic regression models, adjusting for potential confounders. Purchase of inexpensive drinking water was common and associated with greater child malnutrition, diarrhea, and infant and under-five child mortality in the family. Greater efforts must be made to ensure access to safe drinking water, a basic human right and target of the Millennium Development Goals, in urban slums.

Contact: Prof. Richard Semba, Department of Ophthalmology, Johns Hopkins University School of Medicine, USA, e-mail: rdsemba [at] jhmi.edu

Schistosomiasis: no funding, more worms in Mali

After a donor-funded national schistosomiasis control programme in Mali ended in 1992, the organ-destroying worm disease that affects about 200 million people worldwide (World Health Organization) rebounded within 12 years, according to a recently published medical study.

The disease can damage the bladder, ureters, kidneys, liver, spleen and intestines.

Even though endemic communities in Mali received intensive treatment and health education on schistosomiasis from 1982-1992, the infection was still as widespread nationwide in 2004 as earlier decades, according to researchers.

Despite the 10-year programme, study leader Archie Clements from Australia’s The University of Queensland said control needs to be delivered even longer – “over a very long time period” – to have a lasting impact.

Since Malian government funding for schistosomiasis ended in 1998, the disease received little attention until the Bill & Melinda Gates Foundation-funded Schistosomiasis Control Initiative started in 2004.

Source: IRIN, 08 May 2009

Tanzania, Dar es Salaam: seeking low-cost solutions to sanitation crisis

In 2006, Jenna Davis and Alexandria Boehm of Stanford University, were awarded a two-year Environmental Venture Projects grant from Stanford’s Woods Institute for the Environment to find solutions to the problem of diarrhoea-related deaths among children in Africa.

The focus of the study is Dar es Salaam, the largest city in Tanzania. Historically, residents of the peri-urban communities surrounding Dar have relied on water from surface sources or shallow wells that are in close proximity to household pit latrines. “That means when people defecate, the waste stays under the house,” said Davis, an assistant professor of civil and environmental engineering and a fellow at the Woods Institute. “As a result, those shallow wells are very vulnerable to microbial contamination.”

To address the situation, city water and sanitation officials have drilled a series of bore wells that tap into clean aquifers deep below the surface. High-quality water is then pumped into storage tanks connected to sets of four to six taps. “Most of the water from the bore wells meets the World Health Organization guidelines for E. coli bacteria in drinking water,” said Boehm, an assistant professor of civil and environmental engineering. “Concentrations are typically less than 1 bacterium per 100 milliliters water.”

For a little money, residents can go to the taps and carry clean water back to their homes. Many people use the bore-well water for cooking and drinking. But so far, there has been little improvement in their overall health. City water officials want to know why and have turned to the Stanford team for answers.

In the summer of 2008, Davis, Boehm and a team of Stanford students and postgraduates traveled to Dar to study 300 households over a 10-week period. The research team hired Tanzanian enumerators to conduct surveys and interact directly with the households. The enumerators visited each household four times. On the first visit, they collected behavioral information, primarily from female heads of households (“the mothers”), and tested stored water and the hands of family members for indicators of fecal contamination.

Approximately 7,000 water and hand samples were collected during the study. Laboratory analysis revealed very high levels of bacterial contamination on the hands and in the stored drinking water of study participants, even though the deep bore-well water collected at the source was generally of good quality.

“There appears to be something in the transport and storage that is contaminating the water,” Davis explained. “It’s probably happening when people use their fecal-contaminated hands to scoop water out of their home containers. Another possibility is that the stored water containers used for fetching water are not cleaned regularly.”

A major challenge facing many households is distance. Some homes are 200 yards from the clean tap water, and a typical water container weighs 44 pounds when full. “We know that when people haul water from a distance, the first thing they do is drink it, then they cook, and then they wash their kids, themselves and sometimes their animals,” Davis said. “So they may not have enough water for adequate personal hygiene.”

For the second round of visits, the researchers separated the households into four groups. Each group was given generic information about how germs are spread through the five F’s—feces, flies, field, food and fingers. “We used pictures showing several ways to prevent the spread of germs, such as boiling or chlorinating the water,” Davis explained. “One of the four groups received only the generic information. A second cohort got the generic information plus the results of their water test. The third cohort got the generic information and their hand test results. The fourth group got everything—generic information, the water test results and the hand test results. The idea builds on basic health behavior-change theory: The more tailored and less generic the message is, the more effective it should be at motivating change.”

The preliminary results were surprising. Groups that received hand data or water data alone seemed to have a more positive response than households that got both hand and water test results. “It turns out that more is not better,” Davis said. “Even though we spent an equal amount of time discussing water-related strategies and hand hygiene-related strategies, there was a bigger behavioral change on the hand hygiene side than on the water side.”

The researchers are in the process of finalizing the survey data from their Environmental Venture Project. Meanwhile, in September 2008, Davis and her colleagues were awarded a three-year National Science Foundation grant to expand the number of households and the length of the study. “We’re aiming for a full year, which would allow us to monitor behaviors in both the dry and wet seasons,” she said. Data collection will begin in mid-2009, and the results could lead to low-cost solutions that reduce the incidence of diarrhea for tens of millions of children in sub-Saharan Africa and throughout the developing world.

Other members of the Stanford research team are Gary Schoolnik, professor of medicine and of microbiology and immunology; Abby King, professor of health research and policy and of medicine; and Cynthia Castro, research associate at the Stanford Prevention Research Center.

Source: Mark Shwartz, Stanford University News, 22 Apr 2009