The presence of radiotoxic 210Po and 210Pb in Ukrainian wild medicinal plants and the assessment of related dose and cancer risk

Herbal plants are considered natural pharmaceuticals but also accumulate chemical elements and compounds at high levels. ²¹⁰Po and ²¹⁰Pb are highly radiotoxic and may cause carcinogenesis due to ionizing radiation. Thirteen of the most popular wild-growing herbaceous plant species, mostly included in the European Pharmacopoeia, were collected across Ukraine. ²¹⁰Po and ²¹⁰Pb were determined in the medicinal plants, and their radiotoxicity and cancer risk were calculated. The results of ²¹⁰Po activities measured in herbal raw material ranged from 2.28 Bq kg^-1 dw (where dw is dry weight) in herb of common horsetail (Equisetum arvense L.) collected near Lviv to 37.7 Bq kg^-1 dw in leaves of common birch (Betula pendula Roth.) from Rava Ruska. The activity concentrations of ²¹⁰Pb varied from 0.44 Bq kg^-1 dw in leaves of common birch from Starokostyantyniv to 28.4 Bq kg^-1 dw in leaves of common birch from Mizhhirya. There were statistically significant differences between ²¹⁰Po and ²¹⁰Pb content in flowers, leaves, and aerial portions. The studies indicated that the estimated annual effective radiation dose from Ukrainian herbs consumption was low, ranging 5.00-82.6 µSv from ²¹⁰Po and 0.56-35.8 µSv from ²¹⁰Pb, while the cancer morbidity and mortality risk ranged from 10^-4 to 10^-6. The presented data indicated no radiological risk related to using herbal plant materials.