Distribution and biokinetic analysis of Pb and Po in poultry due to ingestion of dicalcium phosphate

Dicalcium phosphate (DCP) is used as a calcium supplement for food producing animals (i.e., cattle, poultry and pig). When DCP is produced via wet acid digestion of the phosphate rock and depending on the acid used in the industrial process, the final product can result in enhanced ²¹⁰Pb and ²¹⁰Po specific activities (∼ 2000 Bq·kg⁻¹). Both ²¹⁰Pb and ²¹⁰Po are of great interest because their contribution to the dose received by ingestion is potentially large. The aims of this work are to examine the accumulation of ²¹⁰Pb and ²¹⁰Po in chicken tissues during the first 42 days of life and to build a suitable single-compartment biokinetic model to understand the behavior of both radionuclides within the entire animal using the experimental results. Three commercial corn-soybean-based diets containing different amounts and sources of DCP were fed to broilers during a period of 42 days. The results show that diets containing enhanced concentrations of ²¹⁰Pb and ²¹⁰Po lead to larger specific accumulation in broiler tissues compared to the blank diet. Radionuclides do not accumulate homogeneously within the animal body: ²¹⁰Pb follows the calcium pathways to some extent and accumulates largely in bones, while ²¹⁰Po accumulates to a large extent in liver and kidneys. However, the total amount of radionuclide accumulation in tissues is small compared to the amounts excreted in feces. The single-compartment non-linear biokinetic model proposed here for ²¹⁰Pb and ²¹⁰Po in the whole animal takes into account the size evolution and is self-consistent in that no fitting parameterization of intake and excretions rates is required.