Natural Radioactivity in various types of environmental and drinking waters in El Salvador

Abstract

Drinking water quality is a topic of concern for the population, and the presence of radioactive contaminants is considered a health risk. The objective of this study was to measure the concentrations of radon gas (²²²Rn) and radium (²²⁶Ra) in drinking and environmental waters and compare them with the radiological parameters outlined in Salvadoran technical regulations for water for human consumption, as well as international regulations. The aim was to contribute to the radiological monitoring of drinking water and various types of environmental waters that could be used for purification. Samples were collected and analyzed intermittently between 2016 and 2019, and again from 2021 to 2022 in different parts of the country. Liquid scintillation counting was applied for analysis, using the standardized method ASTM D5072-09 for radon-222 and the IAEA ARCAL LXXIX method for radium-226. All results showed the presence of radon-222 in different concentrations ranging from 0.91 ± 0.09 to 60.16 ± 2.0 Bq/L. However, the presence of radium-226 could not be determined at concentrations higher than the method's detection limit (0.045 Bq/L). At the monitoring sites, variation in radon concentrations that can be attributed to recurrent seismic events in the region was observed, and this study shows a correlation between seismic events and increases in radon concentrations on specific dates. This study's conclusions suggest the need to continue and expand radiological monitoring of radon and radium to other areas, considering that the country is influenced by seismic and volcanic activity.