Radon concentration in hydrogeothermal deposit and spas of Boyacá, Colombia

Inhaled radon and its progenies induce health concern due to high activity-concentration in selected thermal spas of Boyacá region. Hydrogeothermal water sources in a high risk seismic area, are studied to determine by water bubbling method radon concentration values; their occurrence is between few hundreds and 2000 Bq dm−3. Deposits, existing in this area, reach at the surface soil gas radon concentration up to 210 kBq m−3. Maintenance workers, health tourists and visitor's possible detrimental health effects, are discussed in relation to radon balneotherapy beneficial aspects. •Inhaled radon risk to the health of the employees.•Radon concentrations in the hot springs.•Radon content reduction in thermal spas consists of diluting the geothermal water concentration with fresh water.•Hot springs negative aspect is not confirmed by experimental result (below 20 mSv a-1).