Transfer of 137Cs in two farm ecosystems. Calculated effects of counter-measures following a postulated fallout land contamination.
1988
Andersson I. | Loensjoe H.
Studies were performed on two farms, B and R, in southern Sweden to calculate the consequences after a postulated nuclear reactor accident involving contamination of land by 137Cs (1 MBq per m2). The activity transfer to crops and animal products during the sixth year after the fallout was calculated for situations without and with counter-measures taken. The effects of counter-measures, fertilizing with potassium, deep-ploughing and also modified crop and animal production, were supposed to have reached all parts of the agricultural systems. Steady state conditions were assumed to be prevailing in both situations. Calculations based on the present (in 1985) production on the farms and compiled for the situation without any counter-measures taken, indicate the root uptake of 137Cs in the crops during the year to be 53 MBq (B) and 280 MBq (R) corresponding to 1.0 and 1.6 MBq per hectare, respectively. Through the crops 46 MBq (B) and 187 MBq (R) are ingested by the animals. On the basis of the mean daily activity intake per animal, a total of about 5 MBq on each farm is calculated to be transferred to the animal products (milk and meat). Related to the land area this corresponds to 0.09 and 0.03 MBq per hectare on B and R respectively. The mean internal radiation dose during the year per person on the farms through home-produced food is calculated to be 0.1 mSv (B) and 0.2 mSv (R), and the mean external radiation dose to people working on the farms to be the same as that from the natural background. Calculations for the year in the situation with counter-measures taken indicate that the transferred activity of 137Cs to the crops per hectare is reduced by factors of 10 (B) and 3 (R). The corresponding transfer to animal products is by factors of 23 or 45 (B) and 3 (R), although in the latter case the size of animal production is considerably increased. The external and possibly also the internal radiation doses to people on both farms will be reduced.
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