Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Monocultures of freshwater green algae Ankistrodesmus sp. and Selenastrum sp. cultured in dilute solutions of metals chelated with EDTA, revealed massive uptake of U and Ba. For 2 ppm metal-spiked TBIM culture media at pH 8.1-8.2 and growth durations of 3-21 days at 13-16(DEGREES)C, both species accumulate U and Ba at levels of 1,000 to 10,000 ppm by dry weight. Uptake was comparable for passage of 100 ml spiked culture media through algal mats over 100 min. For 2 ppm Co-, Ni- and V-spiked culture media, algal uptake was 40-600 ppm Ni, 17 ppm Co and 12 ppm V, respectively. At 40 and 20 ppb, the algae absorbed 3,000-6,000 ppm U and Ba.;Thames River waters have an average dissolved U of 1.46 ppb (+OR-) 0.61 l(sigma), representing about twice the global mean riverine solute concentration of 0.6 ppb U. Suspended particulates, principally algae, contain U at 10('3) to 10('5) times that of their river habitat, averaging 28,300 ppb U: algae carry about 15% of the total riverine U flux. Seasonal variations of dissolved and algal uranium occur, peaking over the fall and winter months September through February. One community of the filamentous algae Spirogyra sp. contained intracellular crystals tentatively identified as the Ca-oxylate weddelite.;At Elliot Lake, tailings waters contain high concentrations of dissolved uranium along with other heavy metals, and spectacular growths of Euglena sp. In natural drainage waters dissolved U averages 0.23 (+OR-) 0.19 ppb l(sigma), whereas tailings effluent averages 273 (+OR-) 215 ppb l(sigma) Suspended microorganisms, chiefly algae, in natural waters contain an average 19,300 ppb U, and up to 1,200,000 ppb or 1.2% of the cell by dry weight. Euglena communities thriving in tailings waters contain an average 3 x 10('5) ppb U, in addition to (TURN)40 wt. % Fe, Al (14,000-40,000 ppm), Ba (7-90), Co (250), Cu (70-40), Mn (200-500), Ni (80-200), Pb (1300-2000), Si(200-2,000), Sr (50-200), Ti (400-900), V (30-70) and Zn (50-230 ppm), as well as significant Ag, Be, Th and Zr. A reconaissence survey of algae from selected freshwater and marine environments revealed high concentrations of many elements in addition to U, including Ag, Al, Ba, Be, Co, Cr, Cu, Fe, Mn, Ni, Pb, Si, Sr, Th, Ti, V, Zn and Zr.



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