Original Title: Contaminantes procedentes del tratamiento de las aguas de consumo en la Comunidad Autónoma del País Vasco: Evaluación del riesgo y las alternativas de tratamiento

Authors' objectives: Determine the exposure to disinfection sub products of the Population of the Autonomous Community and assess the possibilities of treating raw water and/or adjusting the treatments to reduce the concentration of disinfection sub products.

Authors' results and conclusions: The greatest amount of evidence of the adverse effects on health associated with DSPs exists with regard to bladder cancer. The results with regard to other kinds of cancer and the reproductive effects are not conclusive. The average levels of THMs in the supply areas of the Basque Autonomous Community are under the limit established in Royal Decree 140/2003, and comply with the guideline values recommended by the World Health Organisation (WHO). There are differences in the levels of THMs between Basque Provinces. While in Gipuzkoa, 95% of the population is supplied with water with levels of under 25 μg/L, in Bizkaia, 85% of the inhabitants consume water with the levels of over 50 μg/L. The inhalatory tract may make a significant contribution to the total exposure to DSPs present in water. In areas with a greater content of chloroform, the inhalatory tract has the greatest relative weight. The displacement of the pre-chlorination point and the change in the type of disinfectants used in the treatment have been seen to be efficient measures to reduce a final concentration of THM. Following the recommendations of the 98/83 directive, – to achieve the lowest possible levels of DSPs without compromising disinfection –, there is a margin for improving the quality of water in the supply areas of the Basque Community with the highest levels of THMs. The reduction of the average concentrations of chloroform to levels below 40 μg/L would affect 12 supply areas and 900,000 consumers would benefit.

Authors' methods: A bibliographical survey was made of the origins and effects on health of the most important DSPs in the databases and portals used most widely in the scientific literature. A descriptive statistical analysis has been made as well as an assessment of the risk of THM levels during the period 2004-2009 in the supply areas of the Basque Country that supply more than 500 inhabitants. Lastly, a number of feasible alternatives have been identified to reduce the formation of DSPs by work groups in which volunteer specialists from the control and surveillance units have taken part.

Project Status: Completed

Year Published: 2012

URL for published report: https://www.euskadi.eus/contenidos/informacion/2012_osteba_publicacion/es_def/adjuntos/D-12-01_WEB%20_%20aguas%20de%20consumo.pdf

English language abstract: An English language summary is available

Publication Type: Other

Country: Spain

Organisation Name: Basque Office for Health Technology Assessment

Contact Address: C/ Donostia – San Sebastián, 1 (Edificio Lakua II, 4ª planta) 01010 Vitoria - Gasteiz

Contact Name: Lorea Galnares-Cordero

Contact Email: lgalnares@bioef.eus

Copyright: <p>Osteba (Basque Office for Health Technology Assessment) Health Department of the Basque Government</p>