Soil to plant 137Cs transfer factors in Zea mays and Phaseolus vulgaris in a semi-arid ecosystem from a radioactive waste site

A study of 137Cs in soil, maize plants, (Zea mays) and beans (Phaseolus vulgaris) has been performed at the confined Storage Centre for Radioactive Waste from Mexico. Under field conditions the site was divided in four zones with different soil contamination characteristics. The plants were grown 'in situ' reproducing the local agricultural practices without fertilizers, pesticides or artificial irrigation.The 137Cs determinations were performed using a low background gamma spectrometry system with an HPGe detector. The results indicate that one of the zones had a striking 137Cs contamination in the soil and the uptake by the grown plants showed the highest specific activities at the root. For the edible parts of the plants the amount of 137Cs in the maize grains was one order of magnitude lower than for the beans. The transfer factors ranges for the different parts of the maize plants was from 0.001 in the grain to 0.6 in the root. (author)