Radiological risk assessment of naturally occurring radioactive materials at a quarry site in Rodriguez, Rizal
Abstract
Naturally occurring radioactive materials in quarry environments are of radiological interest because excavation and material extraction can redistribute radionuclide-bearing rocks and soils, potentially increasing external radiation exposure among workers and nearby communities. This study determined the activity concentrations of naturally occurring radionuclides and evaluated the radiological significance of an active quarry site in San Isidro, Rodriguez, Rizal, Philippines. In situ gamma spectrometric measurements were conducted at twelve measurement points using a 3 in × 3 in NaI(Tl) RS-330 portable gamma-ray spectrometer operated in assay mode for 5 min at 1 m above ground level. The activity concentrations of 238U, 232Th, and 40K ranged from 1.235 to 4.94 Bq⋅kg−1, 1.218 to 4.06 Bq⋅kg−1, and 184.67 to 306.74 Bq⋅kg−1, respectively. The computed radiological risk parameters were below the corresponding world average values and lower than those reported in comparable studies from other countries. Overall, the results provide site-specific baseline radiometric data and indicate that the surveyed quarry environment does not present significant radiological risk under the measured conditions.
