Evaluación de las concentraciones de radio-226 en muestras de agua subterránea colectadas en los suministros de agua potable de los cantones Colta, Pallatanga y Cumandá

Abstract

This work focuses on the study of natural radioactivity, specifically on the quantification of radium-226 and radon-222 activity concentrations in water samples, collected from drinking water supplies in the cantons of Colta, Pallatanga and Cumandá, belonging to the province of Chimborazo-Ecuador. All water sources were sampled using the same protocol and the simples were analysed using the emanometric technique, whose experimental setup consisted of a silicon semiconductor detector, incorporated into the RAD 7 monitor detector and the RAD-H2O kit from the Durridge Company of the United States. The results of forty-two measurements of radium-226 activity concentration showed that the highest average value corresponds to the Guacona surface source in Colta (209.10 ± 23.22 Bq/m3) and a value below the limit of detection at the Chilicay river in the canton Cumandá. The highest average level of radon-222 gas was observed in the underground borehole at Cunupogyo underground well in Colta canton (11361.92 ± 120.20 Bq/m3), while the concentration below the level of detection in the Chilicay river, so it could be inferred that radon-222 concentrations in groundwater are much higher than in surface water. All samples had average radium-226 and radon-222 concentrations lower than the level established by Directive 2013/51/EURATOM (0.5 Bq/l) and (100 Bq/l) respectively. Corresponding to the low levels of radon-222 and radium-226 found in the 14 drinking water sources, the annual effective dose from inhalation of radon-222 and annual effective dose from ingestion of radium-226 are relatively small with respect to the recommended values by the European Community therefore it is concluded that the use of water does not present a risk to the health of the population form cantons of Colta, Pallatanga and Cumandá.