RADON IN DRINKING WATER IN COUNTY WICKLOW - A PILOT STUDY

Abstract

A pilot study of radon in drinking water has been carried out by the Radiological Protection Institute of Ireland (RPII) with the assistance of Wicklow County Council. County Wicklow was selected for the study primarily on the basis that the underlying geology is predominantly granite with known elevated concentrations of uranium, which ultimately decays to radon. Radon activity concentrations were measured in tap water from the private groundwater supplies of 166 houses in County Wicklow. Four houses had activity concentrations in excess of the recommended EC action level of 1,000 Bq/l for private drinking water supplies, 15 had activity concentrations between 500 and 1,000 Bq/l, 51 were between 100 and 500 Bq/l and 96 had activity concentrations below 100 Bq/l. Further studies were also carried out on the four houses with activity concentrations above 1,000 Bq/l, including additional measurements of radon in drinking water and radon in air measurements. An assessment of temporal trends in radon activity concentrations in one house was also carried out. Dose estimates based on measurements made in this study demonstrate that radon in drinking water may pose a significant additional health risk, in the longer term, to some consumers who depend on private groundwater supplies as their source of drinking water.