Transfer of radiocobalt from soil to selected plant species in tropical environments

Soil-to-plant transfer factors (TFs) of radiocobalt (60Co) were determined in pot experiments for leafy vegetation, root crops and rice grown in the tropical environment of Bangladesh. Soil properties were also measured to establish a relationship between these properties and TF values. Measured TF values of 60Co for leafy vegetation (average of 2.2 x 10(-2)) were slightly higher than the values obtained for root vegetation (average of 1.6 x 10(-2)). However, TF values obtained for rice (average of 1.17 x 10(-2)) were about a factor of 2 lower than the values obtained for leafy vegetation. TF values of 60Co for leafy vegetation and root crops were observed to decrease with increasing pH, exchangeable K+ and clay content in the soil, even though poor correlations were estimated statistically. No consistent relationship between the TF value for 60Co and organic matter content could be deduced. The results presented here provide a useful addition to existing databases on soil-plant transfer for 60Co, since this information is still rather sparse for tropical environments.