Po and 210 Pb in the Terrestrial Environment Bertil

The natural sources of 210Po and 210Pb in the terrestrial environment are from atmospheric deposition, soil and ground water. The uptake of radionuclides from soil to plant given as the soil transfer factor, varies widely between various types of crops with an average about 0.056±0.003. The atmospheric deposition of 210Pb and 210Po also affect the activity concentrations in leafy plants with a deposition transfer factor for 210Pb is in the order of 0.1-1 (m2.Bq-1) plants and for root fruits it is < 0.003, Corresponding values for 210Po are about a factor 3 higher. The activity concentration ratios between milk and various types of forage for 210Pb were estimated to 1.4±0.7 and for 210Po to 0.41±0.09. By a daily food intake of 16 kg dry matter per day the transfer coefficient Fm. for 210Pb was estimated to 0.01±0.008 d.l-1 and for 210Po 0.003 ± 0.0007 d.l-1. The high accumulation of 210Po in the food chain Lichens (Cladonia alpestris)-Reindeer was used as a model for quantifying it ́s transfer to man. Keywords210Po; 210Pb; Terrestrial Environment; Soil; Water; Plants; Lichen; Milk; Reindeer; Man