Nearly three years ago Duncan reviewed the catastrophic problems of arsenic contamination in drinking water occurring in Bangladesh (this post itself was a follow-on of what we had written about this issue in our book together in 2005). The problem stems from use, during the last 20 years, of millions of small tube-wells, inserted into the ground at depths of usually less than 200 metres then capped with a metal hand pump. Ironically, many of the first wells were constructed by NGOs as part of various programmes to provide “safe” drinking water. Indeed litigation arose when a Bangladesh NGO took the British Geological Survey to court claiming that as participants in the programme, the BGS owed users a ‘duty of care’ to protect them against arsenic poisoning (a claim ultimately thrown out by the House of Lords in 2006).

It’s long been known that arsenic contamination of groundwater is a global problem. Contamination has been found in many other countries, including Argentina, Chile, China, India, Mexico, Taiwan, Thailand and the United States. Bangladesh’s plight however is unprecedented. It’s thought that between 35 and 77 million people out of the country’s total population of 125 million are at risk of exposure to arsenic in their drinking water.

Photo: Skin lesions from arsenic poisoning. Source: http://www.flickr.com/photos/waterdotorg/3695494611/
Photo: Skin lesions from arsenic poisoning. Source: http://www.flickr.com/photos/waterdotorg/3695494611/

In Western Europe many people believe that arsenic contamination is not a present-day problem and that the problem suffered by our nineteenth century forebears who where poisoned by damp green coloured wallpaper that gave off volatile arsenic compounds has long been excluded from our modern lifestyle. However the mechanism of arsenic contamination is not always that straightforward. Although much of these poisonings took place in the nineteenth century it was not until the turn of the twentieth century that arsenic greens were finally phased out. The mechanism of how these damp wallpapers gave off a volatile arsenic containing gas was only fully identified in the 1930s (it’s known as Gosio’s gas after the Italian chemist who first smelt its ‘garlic smell’, see here).

Recently arsenic came back to haunt Italy in another form. Just last month, Health Minister Renato Balduzzi warned of high arsenic levels in drinking water in 50 cities and towns in the Lazio region around Rome. This ‘true emergency’ that ‘cannot wait any longer for a solution’ was revealed after a study showed the level of arsenic in those who have drunk water in and around the town of Viterbo was twice that of the general Italian population.

This very recent news of course reminds us that the arsenic problem still raises its head in the developed world (even on occasions in the USA). Nevertheless it is the poor of the world that really suffer. We suspect that ‘urgent measures’ is a term used by all politicians across the world. In Bangladesh many similar expressions have been used many times. However as the recent clothing factory collapse in this extraordinarily poor country has demonstrated, protection of its citizens against risk is woeful.

When Duncan first posted his story in 2010 that was already eight years since a Bangladeshi Prof. Abul Hassam, working in Virginia USA, had first reported to a world conference on arsenic poisoning in the USA about a new water filter based on crushed bricks heated together with ferrous sulphate as an available, maintenance-free and cheap solution (originally predicted to be about 3 USD). Hassam was awarded the 1 million USD Grainger challenge prize by the National Academy of Engineering in 2007. This allowed him to develop his filter after years of testing hundreds of prototypes. His ‘Sono’ arsenic filter removes arsenic to a level below that recommended by the WHO, although the cost, as so often happens, rose by more than a factor of ten over original estimates, becoming about 35 USD per family-size unit.

This technology is not without its critics. Some academics at Kansas (see also here) suggest that despite Hassam’s claim that the arsenic is locked into the material, the disposal of the filter material at end of life (two years with normal use) represents a serious pollution threat to Bangladesh’s land water and air. There are also competing technologies – e.g. a very similar one, from the University of Berkeley uses a stabilised ‘bottom ash’ waste product from coal burning power stations instead. Processes based on ‘cysteine’ and citric acid are also available, which use waste plastic bottles as a substrate.

Sadly all these processes featuring high-tech Western technologies will produce a high arsenic content toxic waste. Given the huge size of the problem in countries like Bangladesh where the controlled disposal of toxic waste is very limited then safe disposal of this arsenic may well become a major problem. A new publication, Arsenic Contamination in the World: An International Sourcebook by Susan Murcott at MIT for the first time has measured the problem and summarised representative arsenic remediation and safe water supply options. Murcott indicates that on top of the variety of hardware options to consider the ‘software’ issues like behaviour, operation and maintenance, financial and technical sustainability – and I would add the sheer magnitude and endemic nature of the problem – are far more difficult to overcome.

Overall in the three years since Duncan’s post, sadly although the situation for a few has improved I suspect the full magnitude of the difficulties to resolve the problem is still coming to light.

Roger Ford

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