Activity of ¹³⁷Cs and ⁴⁰K Isotopes in Pine (<i>Pinus sylvestris</i> L.) and Birch (<i>Betula pendula</i> Roth) Stands of Different Ages in a Selected Area of Eastern Poland

• Main Authors: Małgorzata Strzałek, Katarzyna Barczak, Jadwiga Karwowska, Elżbieta Królak
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Forests
• Subjects: radiocesium; potassium; wood; soil; litter; radioactive contamination
• Online Access: https://www.mdpi.com/1999-4907/12/9/1205

Research Highlights: a forest is an ecosystem that allows for the assessment of radioactive contamination of the environment over several decades. (1) Background and Objectives: measurements of the activity of the ¹³⁷Cs isotope in various elements of a forest ecosystem are one of the most important parameters in the assessment of radioisotope contamination. The translocation of ¹³⁷Cs in the environment is determined by the activity of the natural ⁴⁰K isotope in soil. The activities of ¹³⁷Cs and ⁴⁰K isotopes were assessed in two stands of <i>Betula pendula</i> and <i>Pinus sylvestris</i>, differing in age (30, 50, and 80 years old); (2) Materials and Methods: the research was conducted in one of the forest districts of eastern Poland. Wood, litter, and soil were collected for the tests from the sampling sites. The activity of ¹³⁷Cs and ⁴⁰K was determined using the γ-spectrometric method. Based on the activity of these isotopes in wood and soil, the values of translocation factors (TF) were determined; (3) Results: the highest activity of ¹³⁷Cs was recorded in the wood of the oldest stands, the growth period of which coincided with the time period of intensive testing with nuclear weapons. With the growing age of the stand, the value of TF ¹³⁷Cs increased, while the value of TF ⁴⁰K was not dependent on the age of the stands. Birch wood accumulated more ¹³⁷Cs and ⁴⁰K isotopes than pine wood. (4) Conclusions: the results show a much greater radioactive contamination of the environment in eastern Poland during the testing with nuclear weapons than after the Chernobyl nuclear reactor explosion. The greater accumulation of radiocesium in birch wood than in pine wood predisposes this species to be more useful when assessing the radioactive contamination of the environment from the past.