Preliminary Assessment of Radiation Dose Levels and Potential Health Risks in Thermal Spa Environments

This preliminary study evaluates beta and gamma radiation levels and related health risks in two Algerian thermal spas, H1 and H2. We focused on doses received by workers and visitors, especially near thermal pools and confined treatment rooms. Dose rates were measured using a LUDLUM 2403 radiometer with a Geiger–Müller detector under different conditions: ventilated vs unventilated rooms and empty vs water-filled pools. Absorbed dose rates ranged from 1.2×10⁻4 to 3.18×10⁻4 mSv/h for H1 and from 1.7×10⁻4 to 3.55×10⁻4 mSv/h for H2, higher in humid, unventilated areas. Annual effective doses for workers varied between 0.15–0.27 mSv/y in H1 and 0.19–0.40 mSv/y in H2, while visitor doses remained very low (≤ 0.01 mSv/y). Excess lifetime cancer risk (ELCR), the annual inhalation equivalent dose to the lung (EInh), and estimated lung cancer per million people per year (LCC) cases were all well below internationally recommended reference levels showing negligible long-term risk. Benchmarking against international studies shows that our measured values are consistent with reported data. These results highlight the importance of ventilation to limit radon accumulation and provide a baseline for further studies in Algerian thermal facilities.