Potential bio-indication for soil contamination in semi-tropical area

Three kinds of common plant: bastard banian (Ficus retusa), hsianshih trees (Acacia confusa) and pine trees including their cones grown in semitropical areas were investigated to serve as bio-indicators for 137Cs contamination in soil in Taiwan. Gamma spectroscopy was performed to measure the concentration of 137Cs in soil and different parts of the plants. The results indicate that either the pendent rootlets of the bastard banian or the pine tree including its cones can be used as bio-indicators for environmental radioactivity monitoring. Though the effectiveness of the hsianshih tree as an indicator is known to be inferior to others, its popularity makes it a potential bio-indicator in semitropical area.