Assessment of radioactive contamination of medicinal plants of meadow ecosystems of the Sozh River floodplain 30 years after the accident at the Chernobyl nuclear power plant

Abstract

The aim of the study is to assess the radioactive contamination of medicinal plants of economic types of meadow ecosystems of the Sozh River floodplain. The objects of the study were medicinal plants of the floodplain of the Sozh River. Soil samples and plant samples were taken for radiological analysis within the boundaries of the selected economic types of meadows. Determination of 137Cs content in soil and plant samples was carried out on the Tennelec. Characteristics of the selected economic types of meadows. 12 species of medicinal plants were analyzed on each type of meadow. In the meadow large-sedimented type, the specific activity of soils in 2015 amounted to 1600 Bq/kg, and in 2020 – 1380 Bq/kg. Radiological analysis of the specific activity of aboveground phytomass in 2015 and 2020 showed that all plant samples did not exceed the republican permissible level of 137Cs content in medicinal technical raw materials – 370 Bq/kg, with the exception of the pure Stahyis palustris swamp, the permissible level of which was 10 Bq/kg higher. In the turf type of meadows, the specific activity of soils in 2015 was 116 Bq/kg, and in 2020 – 970 Bq/kg. In this type of meadow, all plant samples did not exceed the permissible level of 137Cs. In the meadow coarse-grained type, the specific activity of soils in 2015 was 1380 Bq/kg, and in 2020 – 1150 Bq/kg. In 2015 and in 2020 all plant samples corresponded to the permissible level of 137Cs content, only in the meadow foxtail in 2015 the specific activity exceeded the permissible level by 155 Bq/kg. In the fine-grained type of meadows, the specific activity of soils in 2015 was 962 Bq/kg, and in 2020 – 704 Bq/kg. Both in 2015 and in 2020, the specific activity of all plant samples was below the permissible level. A comparative analysis of the specific activity of medicinal plants of the studied economic types of meadows shows that in 2020, compared to 2015, has decreased by an average of 1,3 – 1,4 times, the greatest specific activity of plant samples over the years of observation was observed in the meadow type with large leaves, which is 4 times more than in a fine-grained meadow. The decrease in radioactive contamination of medicinal plants occurred with a simultaneous decrease in the density of radioactive contamination of the soil.