Assessment of cancer risk and radiological effects from Po and Pb with consumption of wild medicinal herbal plants.

Background: Plants' raw materials can accumulate chemical elements, including radioisotopes, to some extent and reflect the region they grow in. Due to their high environmental content and toxicity, natural radionuclides - polonium Po and lead Pb are the most dangerous radioisotopes for human health.

Methods: 70 raw medicinal herbal materials from 54 popular wild-growing medicinal plant species, most of them included in the European Pharmacopoeia, were collected across three regions. In 210 samples, the activity concentrations of Po and Pb were determined, and their radiotoxicity and cancer risk were calculated.

Results: The results of Po and Pb activities measured in herbal raw material were from 0.12 mBq g dry weight in the fruits of the common chestnut (Aesculus hippocastanum) to 19.7 mBq g dw in herb of ground elder (Aegopodium podagraria) for Po, while for Pb ranged from 0.16 mBq g dw to 34.3 mBq g dw in the same plants. There were statistically significant differences between Po and Pb content in leaves, herbs, flowers, and fruit. The studies indicated that the estimated annual effective radiation dose from Polish medicinal herbs consumption was low, ranging 0.03-105 µSv from Po and 0.02-98.2 µSv from Pb, while the risk of cancer morbidity and mortality ranged from 10 to 10.

Conclusions: Consumption of the tested medicinal herbs is safe from the radiological point of view and, based on the predictions related to the calculated risk of cancer, should not increase the probability of its occurrence.