(137)Cs and (40)K isotopes in forest and wasteland soils in a selected region of eastern Poland 20 years after the Chernobyl accident.

The vertical (137)Cs profile of forest and wasteland soils was analyzed in the south of the Podlasie Lowland area (Eastern Poland) about 20 years after the Chernobyl accident. In addition, the concentration of (40)K in soils of the investigated area was measured. Below the litter layer (mean thickness 3 cm), the soil samples were collected up to a depth of 12 cm and then divided into three layers: 0-3, 3-7, 7-12 cm. The behavior of (137)Cs and (40)K isotopes in soils was analyzed depending on the depth from which the soil samples were collected, as well as on the content of organic carbon, pH of soil and its granulometric composition. It was established that the density of (137)Cs in the litter layer equals 2.17 kBq m(-2); it is the highest in layer 0-3 cm where it equals 3.44 kBq m(-2), and it decreases with the depth to the value of 0.76 kBq m(-2) in layer 7-12 cm. No similar pattern was observed in wasteland soils. The concentrations of (40)K in forest and wasteland soils did not change significantly with depth.