Entry of technetium-99 into the human food chain through the use of seaweed as soil conditioner

Department of Environmental Science, University of Stirling, Stirling FK9 4LA, U.K.

Abstract

The accumulation of ⁹⁹Tc by Fucus vesiculosus and its subsequent use as a soil conditioner in coastal areas gives rise to a potential pathway for the transfer of ⁹⁹Tc to terrestrial ecosystem and on to humans. Preliminary results from a small-scale study of the release of ⁹⁹Tc from Fucus vesiculosus into a sandy, coastal soil suggest that around 20 % of the ⁹⁹Tc present in the seaweed is released within 17 days (2.7 weeks) of its addition to the soil, even though the decomposition rate, measured by the CO₂ production of soil microorganisms, remained low over that period. Further analyses will be carried out to determine the rate of ⁹⁹Tc release in the latter part of the experiment when the decomposition rate had increased.