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Influence of salinity and eutrophication on bioaccumulation of 99 technetium in duckweed
Author(s) -
Hattink Jasper,
Wolterbeek Hubert Th.,
de Goeij Jeroen J. M.
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620200509
Subject(s) - bioaccumulation , environmental chemistry , lemna minor , chemistry , brackish water , salinity , bioconcentration , aquatic plant , radiochemistry , ecology , biology , macrophyte
This study concerns the bioaccumulation of the long‐lived nuclear waste product 99 Tc in duckweed ( Lemna minor L.). 99 Tc was present as the oxyanion TcO 4 − , being the main chemical form of technetium in aerobic water systems. In contrast with terrestrial plants, bioaccumulation in duckweed proved to be independent of the nitrate concentration in the medium. However, uptake is controlled by electrostatic effects in the cell wall, which affects the bioaccumulation of 99 Tc in duckweed in natural environments. These waters are characterized by a range of salinity and hardness, and this study suggests that this may result in up to a threefold difference in 99 Tc accumulation. Because of screening of negative charges in the cell wall, the highest accumulation may be expected in hard, brackish water. This behavior can be described by a general model, which includes electrostatic effects and binding of cations at the cell wall. The model also explains why cationic radionuclides are preferably taken up in soft, fresh water while anionic species are concomitantly taken up in hard, chlorine‐rich waters.