A team led by Dr Parvez I. Haris from De Montfort University, Leicester, United Kingdom have developed a cheap and effective way of removing arsenic from water which may benefit the health of millions of people in many countries around the world including Bangladesh which is the victim of one of the largest mass poisonings in human history.

Their approach is based on using a powdered material produced from the roots of a plant, water hyacinth, which flourishes as a weed in ponds, lakes and rivers in many parts of the world. A variety of health problems are linked to arsenic exposure and ingestion including cancer, cardiovascular and neurological diseases. In Bangladesh, consumption of tubewell water that is naturally enriched with arsenic has placed the lives millions of people at risk from developing such debilitating diseases. The tubewells were installed after 1970, in order to reduce incidences of diarrhoea and cholera related to the consumption of surface water. Unfortunately, the level of arsenic in the tubewell water was not tested to ensure that the water was safe to drink. There is now urgent need for developing methods that can remove arsenic from tubewell water and the method developed by Haris and his team provides an approached based on a plant based biomaterial which is available in large quantities in Bangladesh.

Delighted by his discovery which has been published as advance article in Journal of Environmental Monitoring (http://www.rsc.org/is/journals/current/jem/jempub.htm), Haris recalls his “Eureka” moment when he first thought of the idea during a visit to Bangladesh where over 70 million people are at risk from drinking arsenic contaminated groundwater. "Although, I was aware of the problem my urge to do something intensified when I personally met victims of arsenic poisoning and witnessed their suffering. Many of these people are extremely poor, and it was obvious that an affordable and effective solution to the problem of arsenic in drinking water had to be found, ideally using materials that are locally abundant. You are not too far from water in Bangladesh, and what struck me most was the ubiquitous water hyacinth flourishing on the surface of many rivers, lakes and ponds that abound the deltaic nation. I thought to myself could this irritating weed be turned into a life saving material for the impoverished people of that country. On my return to Britain, I immediately got working in the lab with my graduate student. We spiked lab water with as much as 200 parts per billion (ppb) of arsenic, similar to the toxic levels found in Bangladesh, and to our amazement the powder derived from water hyacinth roots reduced the water's arsenic concentration to below 10 ppb within minutes. The level of arsenic left in the water was not only below that of the Bangladeshi standard for safe drinking water (50 ppb), but is also below that recommended by the World Health Organisation (10 ppb) and the European Union (10 ppb).” Haris remembers this finding as a moment of “great satisfaction since a plant, regarded as a nuisance, has been turned into a life saving material that can help some of the poorest people in the world, not only in Bangladesh, but also in India, Mongolia, Mexico, Chile and Thailand”.

The water hyacinth plant is often named “green plague” as it can spread rapidly, doubling its size within a few weeks. It is one of the worst aquatic weeds and is found in many countries with hot climate. Haris is pleased that “the use of water hyacinth for removing arsenic is a welcome change for this much maligned, but beautiful, plant. People can harvest the water hyacinth plants, instead of just throwing them away, and store the dried roots for later use during the dry season when the supply of the plant is at its lowest”.

Haris believes that his method is probably the least expensive of all the currently available arsenic removal technologies, and hopes that it will now be exploited in Bangladesh and in other countries. “People can design simple filtration devices containing the dried water hyacinth roots to remove arsenic from water drawn from any one of the millions of contaminated tube-wells in Bangladesh. More work needs to be done on this, but the approach can be put into immediate use for removing arsenic from irrigation water to halt the ever increasing entry of arsenic into agricultural land and crops. This will help reduce arsenic getting into the human and animal food chain”.