Health risk assessment caused by external and internal exposure to radiation dose from naturally occurring radioactive materials in outdoor dust

Abstract

Outdoor dust (ODST), which is the main carrier of toxic elements in urban or industrial environments, is also one of the important sources causing public health problems. ODSTs in the production areas of coal-fired brick kilns generally consist of soil dust, brick dust and coal bottom ash. Therefore, these ODSTs contain naturally occurring radioactive materials (NORMs) such as terrestrial radionuclides in the uranium (238U) and thorium (232Th) decay chains and radioactive potassium (40K). For the first time in this study, radiological health risks caused by the ionizing radiation doses from NORM in ODST samples collected from thirty-one lignite coal-burning clay brick factories in T & uuml;rkiye were assessed for adult workers by estimating total annual effective dose (TAED) due to the external and internal exposure and the corresponding total lifetime cancer risk (TLCR). The elemental concentrations of uranium (U), thorium (Th) and potassium (K) obtained in mg/kg from an energy-dispersive X-ray fluorescence spectrometric analysis were converted to the corresponding activity concentrations in Bq/kg of 238U, 232Th and 40K. The average activity concentrations of 238U, 232Th and 40K in ODST samples were found to be 33.4 (9.9 to 132.1 Bq/kg), 39.4 (21.9 to 59.2 Bq/kg) and 458.9 (328.3 to 712.9 Bq/kg) Bq/kg, respectively, which were comparatively to the worldwide soil average values. The average values of TAED and TLCR were estimated as 84.3 mu Sv and 3.4 x 10-4, respectively. Radiological evaluation revealed that adult workers are exposed to an additional dose of one-fourth of the TAED (366 mu Sv) from external and internal (excluding radon) exposures from natural radiation.