Native plants as sentinels of tritium contamination
This study assessed the potential of six plant species growing in the Mojave Desert, as sentinels of tritium contamination below earthen caps covering radioactive waste. The plants, grown in hydroponic tanks and 3 m columns, were evaluated for treatments representing three different levels of tritium contamination. Tritium, a radioactive isotope of hydrogen, replaces a hydrogen atom in a water molecule and readily migrates through soil. Plant roots coming into contact with soil moisture do not discriminate between tritiated water molecules and dihydrogen water molecules in the uptake process. Plants have the potential to be more effective monitors of radioactive waste-sites than mechanical sensors, because roots sample a larger soil volume. Tissue collection from plants to detect tritium can be completely aboveground, offers the option of transpiration capture or biomass analysis, and potentially exposes technicians to lower levels of radioactivity than encountered during installation and maintenance of in-ground mechanical sensors.
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