Bioavailability of Technetium‐99 as Affected by Plant Species and Growth, Application Form, and Soil Incubation

Soil availability, plant uptake and soil to plant transfer of 99Tc—A review

“…TcO Ϫ 4 does not sorb onto negatively charged "cation" exchange sites and is thus generally reported to be available to pedological and biological processes in aerobic sediments and soils (Zeevaert et al, 1989;Echevarria et al, 1997). Sheppard et al, (1990) found no indication of sorption for a large number of Canadian soil types, whatever the organic matter content.…”

“…TcO 2 can be sorbed to the soil solid phase in reducing conditions by complexation with organic matter, and sorption is enhanced at high clay contents and high pH (Sheppard et al, 1990;Rößler et al, 2000). TcO 2 complexes are re-oxidised very slowly, limiting the release of TcO Ϫ 4 into the soil solution (Sheppard and Evenden, 1991;Echevarria et al, 1997). For example, Tagami and Uchida (1999) noted that a dry aerobic period after waterlogging did not remobilise TcO 2 .…”

“…In fact, numerous studies have shown that, regardless of the Tc concentration in the soil, there is a maximum concentration of about 0.1 mg kg Ϫ1 plant Masson et al, 1989;Echevarria et al, 1997;Krijger et al, 1999). Bell et al (1988) reported that Tc levels in Pisum sativa did not exceed 0.07 ppm.…”

Comportement de radionucléides (Cs, I, Sr, Se, Tc) dans le sol : proposition de valeurs de Kd par défaut

“…Le technétium est aussi présent sous forme de divers oxydes, hydroxydes et carbonates (Jensen, 1980 ;Fattahi et al, 1997). La forme pertechnétate est la plus Kd mobile, car sa sorption sur la phase solide du sol est à la fois faible et réversible (Echevarria et al, 1997). De ce fait, pour des conditions normales de sol (aéré et neutre à basique), le Kd du technétium est proche de 0 L kg -1 Krupka et Serne, 2002).…”

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

“…This practice, while not as widespread as in the past, still occurs on a small scale on the west coast of Britain, where in some instances the seaweed is collected from the shore close to the reprocessing plant at Sellafield. Several studies have shown that "Tc (in the soluble pertechnetate ion form) is readily taken up from the soil by certain plant species [4][5][6][7].…”