| Summary: |
Algal communities play a crucial role in aquatic food chains by transfer and bioaccumulation of selenium to higher trophic levels. The inhibitory effect of selenium compounds in two oxidation states Se(IV) (SeO2, H2SeO3, Na2SeO3) and Se(VI) (Na2SeO4 and H2SeO4(nia)3) on growth, chlorophyll a and chlorophyll b production of algae Desmodesmus quadricauda, Desmodesmus subspicatus, Chlorella vulgaris and Pseudokirchneriella subcapitata was investigated. The effect of selenium compounds was dependent on the concentration and chemical species of the element. All salts of selenium inhibited growth of the algae when compared to controls. For single algae and tested metals, the following rank orders for growth inhibition can be established: D. quadricauda: H2SeO3 = H2SeO4(nia)3 = SeO2 >> Na2SeO3 >> Na2SeO4; D. subspicatus: H2SeO3 >> SeO2 > Na2SeO3 >> H2SeO4(nia)3 >> Na2SeO4; C. vulgaris: SeO2 >> H2SeO3 = H2SeO4(nia)3 > Na2SeO3 >> Na2SeO4; P. subcapitata: H2SeO4(nia)3 = SeO2 > H2SeO3 >> Na2SeO4 > Na2SeO3. D. subspicatus was the most sensitive to selenites, while in presence of selenates, D. quadricauda ex-hibited the highest sensitivity. Alga D. subspicatus appeared to be approximately three times more sensitive to H2SeO3 than D. quadricauda. Na2SeO4 had the weakest and H2SeO3 the strongest inhibitory effect on chlorophyll production of all tested algae. |