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.

On the radiotoxic 210Po in coffee beans worldwide and the impact of roasting and brewing on its extraction into beverages: from the experiments to 210Po content prediction

We determined radiotoxic 210Po in roasted coffee beans from different regions worldwide, the beverages, and tried to create the prediction model of 210Po content based on its growth location. Additionally, the experiments on 210Po losses and extraction were performed to describe the actual exposure to 210Po. 210Po concentrations in coffee beans and brews tuned out low (maximally of 0.20 Bq∙kg-1 and 2.31 Bq∙L-1, respectively). We assessed the impact of the roasting process on 210Po content and its losses at a maximum of 56.7%. During infusion experiments, we estimated the extraction of 210Po to the coffee brew at a maximum of 40.6%. The amount of 210Po in the coffee brew depended on the infusion style and water type. We calculated the effective radiation doses from the coffee drink ingestion. Coffee drinking does not contribute significantly to the annual effective radiation dose worldwide.

Bioaccumulation and retention of Po-210 and Pb-210 in two species of mosses from the zone of influence of the former radium-extracting plants

The presented study was aimed at assessing the ability to accumulate and retain ²¹⁰Po and ²¹⁰Pb in two species of the mosses Sphagnum girgensohnii Russow and Pleurozium schreberi (Willd. ex Brid.) Mitt. Mosses were collected in the zone of influence of the former radium-extracting plants (Komi Republic, Russia). ²¹⁰Po and ²¹⁰Pb activity concentrations in S. girgensohnii varied from 131 ± 15.4 to 221 ± 18.3 Bq kg^-1, and from 164 ± 18.6 to 309 ± 26.1 Bq kg^-1 respectively. In P. schreberi corresponding activity concentrations ranged from 107 ± 18.8 to 328 ± 29.2 Bq kg^-1 and from 117 ± 13.2 to 399 ± 31.1 Bq kg^-1. Activity concentrations of ²¹⁰Po and ²¹⁰Pb in autumn were higher than in summer. In the young parts of the mosses, they were lower than in the old parts. To assess the ability to retain accumulated radionuclides, watersoluble (distilled H₂O), exchangeable (1 M CH₃COONH₄), and acidsoluble (0.1 M H₂SO₄) fractions of ²¹⁰Po and ²¹⁰Pb were isolated from the studied mosses by the method sequential extraction. It was revealed that these fractions in total contained up to 26% of ²¹⁰Po and 39% of ²¹⁰Pb. The results showed that the studied moss species are a good biogeochemical barrier and long-term storage for ²¹⁰Pb and ²¹⁰Po.