The main source of drinking water in the volcanic island of Tenerife (Canary Islands, Spain) is groundwater (ca. 80%), which is extracted through an extremely dense network of galleries and wells (with a total cumulative length of about 1600 km). This is a singular feature compared to mainland territories, where surface water is the main source of drinking water. In addition, in volcanic contexts, radionuclide concentration activity can increase because of enhanced water-rock reactions due to thermal anomalies and carbon dioxide-enriched groundwater. Natural radioactivity in groundwater from this island was measured on 74 samples from galleries, wells and water channels. Gross alpha, gross beta and gross beta without potassium activity concentrations were in the range of 17 years). These values are below the 100 μSv/year reference level of the effective dose recommended by WHO.
