M7 AM Metals in the Environment: Chemistry and Fate Issues
Monday, 14 November 2005: 8:00 AM - 11:40 AM in 327-329

(WAL-1117-828122) Interaction between Chlorella vulgaris and dissolved inorganic selenium species.

Harrison, G, Simmons, D, Wallschlager, D,

ABSTRACT- In this study, we investigated the uptake of the three inorganic Se species selenite [Se(IV)], selenate [Se(VI)] and selenocyanate [SeCN-] by the green algae Chlorella vulgaris. Uptake experiments were conducted at typical ambient Se concentrations (1 and 10 g/L) for four weeks. In all experiments, Se addition had a positive effect on algal growth, confirming previous reports that algae require Se as a micronutrient. Despite high algal densities (typical of eutrophic conditions), we observed no statistically-significant loss of Se from solution in any experiment. In some experiments, we observed evidence of algae-mediated Se species transformations in the aqueous phase. These results suggest that although Se uptake into algae may lead to large increases of Se concentration in algae (and thereby induce ecotoxicological effects), it is not a significant pathway for Se removal from ambient waters, but may indirectly affect Se cycling and fate by causing Se speciation changes.

Key words: Chlorella vulgaris, Selenium, bioconcentration