Determination of natural thorium isotopes (230Th and 232Th) in calcium and magnesium supplements and the potential effective exposure radiation dose for human

On 210Po and 210Pb in algae diet supplements - The assessed radiation hazard of aquatic superfoods

Algae are believed to give health benefits. However, the studies showed they contain toxic elements, including radionuclides, and may affect human health. The study presents the values of activity concentrations of ²¹⁰Po and ²¹⁰Pb in the algae supplements available worldwide for adults. The activity concentrations (Bq/kg dw) ranged from 0.07 to 14.5 (²¹⁰Po) and from 0.06 to 8.48 (²¹⁰Pb). Also, the effective radiation doses and the cancer risk from ²¹⁰Po and ²¹⁰Pb decay ingested with analyzed algal supplements have been assessed. The highest values of annual effective doses have been estimated for ²¹⁰Po in the recommended portion of Spirulina (Arthrospira platensis) from China (59.7 μSv/year) and Diatomaceous earth from the USA (50.4 μSv/year). The cancer morbidity and mortality risk ranged from 10^-4 to 10^-8. The study indicated the activity concentrations of ²¹⁰Po and ²¹⁰Pb were low, and algae supplements for human consumption could be considered safe food.

Chromatin and the Cellular Response to Particle Radiation-Induced Oxidative and Clustered DNA Damage

Exposure to environmental ionizing radiation is prevalent, with greatest lifetime doses typically from high Linear Energy Transfer (high-LET) alpha particles via the radioactive decay of radon gas in indoor air. Particle radiation is highly genotoxic, inducing DNA damage including oxidative base lesions and DNA double strand breaks. Due to the ionization density of high-LET radiation, the consequent damage is highly clustered wherein ≥2 distinct DNA lesions occur within 1–2 helical turns of one another. These multiply-damaged sites are difficult for eukaryotic cells to resolve either quickly or accurately, resulting in the persistence of DNA damage and/or the accumulation of mutations at a greater rate per absorbed dose, relative to lower LET radiation types. The proximity of the same and different types of DNA lesions to one another is challenging for DNA repair processes, with diverse pathways often confounding or interplaying with one another in complex ways. In this context, understanding the state of the higher order chromatin compaction and arrangements is essential, as it influences the density of damage produced by high-LET radiation and regulates the recruitment and activity of DNA repair factors. This review will summarize the latest research exploring the processes by which clustered DNA damage sites are induced, detected, and repaired in the context of chromatin.