This paper presents the results of investigations of the level of contamination by radioactive isotopes of grass and soil of the Polish and Ukrainian Roztocze area. Heavy metal contents in soil were also measured. The highest level of radioactivity was found in the Northwestern part of Roztocze, which may be explained by the close vicinity of industrial centers.
The presence of caesium gave from 0.6 to 22% of the total soil activity at Polish side and from 1.5 to 11% at Ukrainian. The Chernobyl nuclear power plant failure is the main source of radioactive contamination of soil. For most samples, 100% of this caesium came from this source. The mean ⁴⁰K contents made up 57% of the total radioactivity in Polish Roztocze and 54% in Ukrainian. Radionuclides of thorium and uranium series gave 20 to 35% of total activity. The activity of ⁴⁰K in grass gave about 80% of the total radioactivity in Polish Roztocze and 73% in Ukrainian. Other radioisotopes present in grass are mainly ⁷Be and ¹³⁷Cs. Heavy metal contents in plough land soil universally, except at two points, do not exceed acceptable levels.