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Arsenic alert!

Concepción Flores has lived in the community of Los Cementos on the flat plains below Volcán Telica for over 50 years.  She has reason not to be smiling.  She has just discovered that water from her well has concentrations of arsenic 17 times higher than the limit set by the World Health Organisation.  Concepción is not sure when the well was built as it was already there when she arrived and for many years it was her only source of water.  Fortunately she no longer uses this well for drinking because a visiting group of Canadians told her that the water was not safe after Hurricane Mitch in 1998 and a new well was dug.  It is not clear whether the Canadians identified arsenic or whether their advice was based on something else, but this may have saved Concepción’s life as the new well a short distance away has only 3 ppb (parts per billion), well within the guideline value for arsenic concentrations of 10 ppb.  The water from the highly contaminated well is still used for her cattle, though, and now that the arsenic problem has been brought to her attention Concepción has started to wonder whether this is the reason why six of her cows have recently died.

In the neighbouring community of Ocotón, the villagers are not so lucky.  They have only one well and this has 235 ppb of arsenic, 23 times the limit.  This well has also been used for several decades and there is currently no alternative for this small group of families.  High levels of arsenic have affected at least 1,000 people in more than ten communities to the north of Volcán Telica.  It is naturally occurring due to a combination of complex geological and hydrogeological factors, probably related to geothermal activity associated with the nearby volcanoes.

Nuevas Esperanzas is currently undertaking an investigation for the Mayor of Telica in this area.  The location of each well is being mapped and data collected including the depth to water, the type of pump and the use of the water.  The water is tested for pH and total dissolved solids and an analysis undertaken for arsenic using an instrument called the ‘Arsenator’.  Chemical reagents are added to a sample of the water to produce a gas containing any arsenic present.  This gas passes through an impregnated filter paper which turns yellow, orange or brown depending on the concentration of arsenic detected.  Nuevas Esperanzas’ Director and hydrogeologist, Andrew Longley says, “Each sample takes about 20 minutes to process.  There is always a nervous moment as the filter paper is removed.  The yellow dot on the paper may be just another statistic for us, but for the people who use this well this brings bad news.  Chronic arsenic poisoning is a long-term problem.  It takes years for symptoms to develop and by the time we discover the high levels of arsenic it is possible that this water has already been consumed every day over several decades.”

Sometimes called the ‘King of Poisons’, arsenic has been used for murder for thousands of years, with its colourless, tasteless and odourless properties meaning that it goes undetected.  Awareness of chronic arsenic poisoning from low concentrations is much more recent, however, and water contaminated with arsenic has been unknowingly consumed over many years in many different parts of the world.  Symptoms of chronic arsenic poisoning, known as arsenicosis, can start to appear over a period of 2-10 years.  Early symptoms such as muscular weakness and mild psychological effects are non-specific but these lead on to changes in skin pigmentation and other more serious complaints such as liver and kidney disease, skin and other cancers which are ultimately fatal.  It is often the poor who are most affected and it is estimated that over 50 million people have already been affected in South and East Asia where the worst problems have been identified.

Nuevas Esperanzas first heard of the arsenic problem in the municipality of Telica in 2009 after two wells were found to have high levels of arsenic.   We were contracted by the local mayor to help identify an alternative source of water for the affected communities but in doing so started to discover that arsenic is far more common in the area than had previously been recognised.  As the search was widened to find a source of water which was not contaminated, yet more communities were added to the list of those affected by this problem.  Nuevas Esperanzas is now looking for funding to carry out a thorough regional investigation including health surveys to determine the effect of arsenic poisoning on the local population.  It is possible that symptoms have already been diagnosed but have not been specifically related to arsenic because of a lack of the awareness of the problem.

There are a number of potential solutions where arsenic contamination is identified including the use of alternative water sources and, if necessary, treatment of contaminated water, but first we need to discover the full extent of the problem so that we can prioritise resources where the need is greatest.  Nicaragua has previously only had one arsenic related problem, near San Isidro in Matagalpa, and awareness of this issue is relatively limited.  Thankfully there is now a growing wealth of international expertise available and we are in touch with various experts in the UK who have worked on the arsenic problem in Bangladesh where 40% of the country’s population is affected.  Our investigation in Telica will be on-going over the next few months and a concerted effort will need to be made by all relevant stakeholders to raise awareness of this problem and find appropriate solutions for each affected community.

21/10/10