Few technologies effective in removing arsenic, study says

Arsenic in the water supply threatens several hundred million people, according to a study published Friday in BioMed Central’s open access journal Environmental Evidence.

The study concluded that there is a lack of evidence regarding the effectiveness of technologies used to reduce arsenic contamination.

The study is important to Costa Rica because arsenic has been found in the drinking water, mainly in Guanacaste.

In the most recent study researchers from the University of Exeter Medical School compared eight different technologies all of which claim to make drinking water safe. They found that most of the studies reviewed were found to be of poor quality and missing data and that only two technologies showed good evidence of effectiveness, said a release from BioMed Central.

The publisher also said that arsenic is now recognized to be one of the world’s greatest environmental hazards, threatening the lives of several hundred million people. Naturally occurring arsenic leaches into water from surrounding rocks and once in the water supply it is both toxic and carcinogenic to anyone drinking it, the publishing firm explained in a release. It is colorless and odorless and consequently people use it instead of more obviously polluted surface water, it added. Natural arsenic pollution affects 21 countries across the world sometimes reaching a concentration more than 10 times the World Health Organization guidelines, it said.

In Costa Rica, Bagaces and Cañas are among the communities that have arsenic in the public water.

Some residents of Guanacaste have filed a Sala IV constitutional appeal because of their tap water. The Sala IV has asked the government agencies involved to respond.

Arsenic in the water is nothing new because the chemical occurs naturally in the ground.

However, more than a year ago, President Laura Chinchilla declared an emergency based on the problems with the water, and the group of residents said nothing has been done since. Among other requests they are asking the government to build whatever it takes to keep the arsenic out of the water.  This probably will mean bringing water in from elsewhere because the Biomed Central study casts a doubt that technology can cure the problem..

The original presidential decree cited problems in communities in Alajuela province and in the canton of Bagaces, Cañas and La Cruz in Guanacaste. The residents note that arsenic is listed as a cause of cancer.

The problem is well-known, and there have been cases of farm animals suffering due to the arsenic in the water.

Among other agencies, the residents name the Instituto Costarricense de Acueductos y Alcantarillados, the national emergency commission, the Autoridad Reguladora de Servicios Públicos, the Presidencia, the Ministerio de Ambiente y Energies and the Ministerio de Salud.

Arsenic also has been blamed for renal failure, and health authorities are looking into the deaths at a dialysis clinic in Cañas.

Adding to the problem, rice seems to soak up arsenic. International studies have found high concentrations of arsenic in rice, but as A.M. Costa Rica reported, rice in Costa Rica is not checked for such heavy metals.

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