Natural radionuclide activity and ingestion dose assessment in thermal springs of Northeastern Algeria

This study assesses natural radionuclide activity concentrations and their associated ingestion doses in thermal spring waters from Hammam Debagh (Guelma) and Hammam Salhin (Khenchela), northeastern Algeria. High-purity germanium gamma-ray spectrometry was employed to quantify radionuclides from the 238U, 235U, and 232Th decay series, and 40K. All measured activities in Hammam Salhin were below detection limits. In Hammam Debagh showed detectable concentrations of 226Ra (4.53 ± 0.86 Bq l-1), 214Bi (4.89 ± 0.66 Bq l-1), 214Pb (4.27 ± 0.56 Bq l-1), and 212Pb (0.46 ± 0.26 Bq l-1), while 40K was below the minimum detectable activity. The estimated annual committed effective ingestion dose ranged from 58 to 926 μSv y-1 depending on water intake, with 226Ra contributing ~99 per cent of the total. Doses exceeded the WHO reference level of 0.1 mSv y-1 but remained below the International Commission on Radiological Protection (ICRP) dose limit of 1 mSv y-1. These results provide a preliminary radiological characterisation of Algerian thermal waters.