Factors affecting uptake of 131I in Chinese white cabbage (Brassica Chinensis Linn)

The factors affecting the uptake of 131I in Chinese white cabbage (Brassica Chinensis Linn) were studied. The time required for the ratio between the activity in the vegetable (Bq kg−1 dry mass) and the activity in the soil (Bq kg−1 dry mass) to reach equilibrium was around 72 h derived from an investigation period of 145 h. The ratio was also dependent on the mass of the vegetable (increased by more than twice when the vegetable mass was decreased to around 60%), the growth period of the vegetable (almost linearly decreased from 3.0×10−2 to 1.1×10−2 when the growth period changed from 66 to 81 d) and the season of culture, while it was independent of the concentration of 131I applied to the soil. The mean concentration ratio obtained for 51 samples was (6.3±4.4)×10−2.