Several soil and vegetation samples from the environment of Kaiga nuclear power plant site in the south western region of India were analysed for 210Po. The vertical profile, particle-size distribution, seasonal variation and the dry deposition rate of 210Po were measured employing the chemical method and α - counting technique. 210Po activity in soil varies from 17.1 to 228.2 Bq kg-1 with a mean value of 83.3 Bq kg-1. The activity of 210Po is higher in the surface soil (0-5 cm) and decreases as depth increases to 20 cm and remains nearly constant thereafter. The activity concentration is almost uniform in the grain sizes of 350-177 μm and below 177 μm. Pterobryopsis tumida (Hook.) Dix, a plant of the moss family, shows a very high level of 210Po activity - 2724 ± 13 Bq kg-1. Seasonal variation studies show elevated levels of 210Po in vegetation during winter. The annual dry deposition rate of 210Po was 53.4 Bq m-2 yr-1. (C) 2000 Elsevier Science Ltd
