Arsenic Contamination of Drinking Water

Submitted by rhamilton on April 20, 2007 - 8:50pm.

Arsenic contamination of the drinking water used by millions of people in Asia and elsewhere in the Developing World presents a major potential public health crisis. It is ironical that it is ground water accessed by deep tube wells that contains arsenic; these wells have been seen as a means of avoiding the use of surface water which contains little arsenic but is often full of microbes in many regions of the Developing World.
A recent special issue of the Journal of Health Population and Nutrition (JHPN Vol 24:3, September 2006) provides important new information on the extent of the arsenic problem and on strategies to deal with it. Probably children are particularly vulnerable to the toxic effects of chronic arsenic intake. Of special concern are its possible roles in delayed cognitive development and in inducing malignant and non-malignant lung disease in young adults.
The cited JHPN issue provides an important service by bringing this subject to a wide research-oriented readership. It also highlights how much is still to be learned about arsenic contamination of water and its impact on human health. How does it get there? What does it do when it is ingested? What is its impact on the fetus, on children, on pregnant women? What is the geographical distribution of arsenic contamination and what should be done to reduce it? These are some of the issues for which hard data are needed.
As exemplified by several papers in the above JHPN issue, many of the answers to the above questions will require a multidisciplinary approach; this website, www.mother-child.org, with its weblog and other features should be well placed to facilitate discussion and planning of such strategies.

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Child Health Health and Health Research Policy

More information on Arsenic Contamination

Submitted by steven on April 23, 2007 - 7:54am.

The WHO also has an informative web page with statistics and fact sheets about Arsenic in drinking water. Here are some [alarming] quotes:

"Seven of 16 districts of West Bengal have been reported to have ground water arsenic concentrations above 0.05 mg/L; the total population in these seven districts is over 34 million (Mandal, et al, 1996) and it has been estimated that the population actually using arsenic-rich water is more than 1 million (above 0.05 mg/L) and is 1.3 million (above 0.01 mg/L) (Chowdhury, et al, 1997)."

"The number of people drinking arsenic-rich water in Bangladesh has increased dramatically since the 1970s due to well-drilling and population growth."

Until the discovery of arsenic in groundwater in 1993, well water was regarded as safe for drinking.

You can read the entire page here.

intervention strategies - where should the priority be?

Submitted by asharma on August 27, 2008 - 4:04pm.

The literature on arsenic contamination in Bangladesh has seen contributions from many different perspectives. I was intrigued to recently see an attempt to analyze a family's decision to change water source using 'constructive choice models' as a statistical tool to model the decision as a balance of goals or utility functions (Gellman and Hill, 2007), an approach more commonly seen in the econometrics literature. In follow-up studies of Bangladeshi families whose wells were identified with levels > 0.05 mg/l, these authors showed that distance to the replacement well figured more prominently in the decision making process than did the degree of contamination, suggesting that those in most danger were "incorrectly perceiving the risk". Perhaps not surprisingly, higher education levels (for the head of the household) appeared to encourage the switch, either by altering the perception of risk or the impact of distance to a replacement well.

This would suggest that identifying contamination is not enough unless accompanied by vigorous efforts to educate those at most risk as to the dangers. I am not sufficiently familiar with the work being done on the ground to know whether the effectiveness of specific educational interventions need to be better studied, to define the optimal approach to what one would hope is a remediable problem. In addition, the use of novel analytic strategies like 'choice models' suggests a place for studies that better address the motives and constraints that influence decision-making at the individual/family/ or community level, to better target interventions and public health measures.

Atul Sharma MD, FRCP(C)
Pediatric Nephrologist,
McGill University