Nivel de Arsénico en abastecimientos de agua de consumo de origen subterráneo en la Comunidad de Madrid

Abstract

[ES] En 1998 se detectaron en la Comunidad de Madrid concentraciones de arsénico mayores de 50mg/l en algunos abastecimientos de agua de consumo de origen subterráneo, concentración máxima admisible en el agua de bebida en España. El objetivo de este trabajo fue determinar la concentración de arsénico en el agua procedente de abastecimientos subterráneos en la Comunidad de Madrid. Se presentan los resultados de los dos primeros muestreos realizados en el plan de seguimiento de niveles de arsénico establecido. En la primera fase se analizaron muestras de agua de los 353 abastecimientos censados por la Dirección General de Salud Pública de la Comunidad de Madrid. Con estos primeros resultados se realizó una clasificación de riesgo de los abastecimientos. En una segunda fase, seis meses después, se repitieron los análisis en los 35 abastecimientos que se El 74% de los abastecimientos estudiados en la primera fase presentaron una concentración de arsénico menor de 10mg/l; el 22,6% contenía niveles entre 10 y 50mg/l; y en el 3,7% eran superiores a 50mg/l. La mayoría de los abastecimientos con niveles de arsénico superiores a 10mg/l se encuentran situados en la misma zona geográfica. En el segundo muestreo (6 meses después) se incluyeron los 35 abastecimientos clasificados de riesgo. De ellos, 26 presentaron el mismo nivel de arsénico (10-50mg/l) y 9 cambiaron de categoría: 6 pasaron a tener menos de 10mg/l y 3 más de 50mg/l. La vigilancia periódica de la calidad del agua realizada por la Dirección General de Salud Pública ha permitido detectar la presencia de 16 abastecimientos de agua de consumo de origen subterráneo con más de 50mg/l de arsénico, nivel máximo admisible según la legislación vigente en nuestro país. Se han adoptado medidas para evitar el consumo de agua en estos abastecimientos. [EN] In 1998, arsenic concentrations of more than 50 micrograms/l were detected in some drinking water supplies from underground sources in the Autonomous Community of Madrid, which is the maximum permissible concentration for drinking water in Spain. These two facts have meant the getting under way of a specific plan for monitoring arsenic in the drinking water in the Autonomous Community of Madrid. The results of the first two sampling processes conducted in the arsenic level monitoring plan set out are presented. In the initial phase, water samples from 353 water supplies comprised within the census of the Public Health Administration of the Autonomous Community of Madrid were analyzed. A water supply risk classification was made based on these initial results. In a second phase, six months later, the analyses were repeated on those 35 water supplies which were considered to possibly pose a risk to public health. Seventy-four percent (74%) of the water supplies studied in the initial phase were revealed to have an arsenic concentration of less than 10 micrograms/l, 22.6% containing levels of 10 micrograms/l-50 micrograms/l, and 3.7% over 50 micrograms/l. Most of the water supplies showing arsenic levels of more than 10 micrograms/l are located in the same geographical area. In the second sampling process (six months later), the 35 water supplies classified as posing a risk were included. Twenty-six (26) of these supplies were revealed to have the same arsenic level ((10-50 micrograms/l), and nine changed category, six of which had less than 10 micrograms/l and three more than 50 micrograms/l. In the Autonomous Community of Madrid, less than 2% of the population drinks water coming from supplies which are from underground sources. The regular water quality monitoring conducted by the Public Health Administration has led to detecting the presence of more than 50 micrograms/l of arsenic in sixteen drinking water supplies from underground sources, which is the maximum permissible level under the laws currently in force in Spain. Measures have been taken to prevent water from being used from these water supplies. Around 20% of the water supplies studies must take measures in the near future to lower the arsenic concentration to below 10 micrograms/l when the water directive which is currently in the process of being written into Spanish law enters into effect.