Assessment of Uranium and Thorium Co-contaminant Exposure from Incidental Concrete Dust Ingestion

Potential health risks of contaminated media linked to bioavailability and hematotoxicity of uranium-238 (238U) and thorium-232 (232Th) remain uncertain. This study investigates the relative bioavailability (RBA), histopathological, and hematological effects of acute oral exposure to 238U and 232Th in co-contaminated concrete dust using 174 female Sprague Dawley (SD) rats. In order to create a range of 238U and 232Th concentrations, concrete was spiked with uranyl and thorium nitrates ( 50, 100, and 200 mg kg−1). Spiked concretes were then crushed, ground, sieved (≤ 75 µm), and blended uniformly to create co-contaminated concrete dust. SD rats’ diet pellet was amended with co-contaminated concrete dust and orally ingested over a 48-h exposure period. The RBA values of 238U and 232Th in blood samples from rats’ post-exposure were determined as 22.0