Radiological investigation of radon in groundwater around the active Taal Volcano (Philippines) and dose evaluation

Pollutants such as naturally occurring radioactive materials (NORM) are ubiquitous in the environment. Radon-222 is one of the naturally occurring radionuclides that can accumulate in groundwater which poses potential health risks through ingestion and inhalation. This study investigates the groundwater radon concentrations around the active Taal Volcano, Philippines. A total of 86 groundwater samples were collected and analysed using Liquid Scintillation Counter (LSC). Radon concentrations ranged from 4 to 51 Bq/L, with an average of 16.84 Bq/L. About 63% of the samples exceeded the US-EPA and PNSDW limit of 11.1 Bq/L, while none surpassed the WHO limit of 100 Bq/L. The estimated inhalation dose ranged from 16.38 to 61.32 µSv/y, while the ingestion dose surpassed the 100 µSv/y limit for most infants and children. While most groundwater radon levels remain within international safety limits, certain municipalities may require mitigation strategies. Public awareness initiatives and continuous monitoring are recommended to minimize the long-term health risks from radon exposure in groundwater.