The green alga Scenedesmus quadricauda - a subject for the study of inhibitory effects of Cd, Cu, Zn and Fe
1999
Fargasova, A. (Slovak Univ. of Technology, Bratislava (Slovak Republic). Faculty of Chemical Technology)
An aquatic ecotoxicological risk test is presented as the assesssment of inhibitory effect and exposure of five metals (Cd, Cu, Zn, Pb and Fe) on freshwater green alga Scenedesmus quadricauda. The tests were done under laboratory conditions and the inhibitory effect of the individual metals on growth rate and total chlorophyll, chlorophyll-a and chlorophyll-b contents were assessed. From the metals, Cd and Cu had the strongest inhibitory effect on the growth of algal suspension. The least toxic was Fe. Its toxicity for all of the observed parameters decreased with the remaining concentration of this metal in the cultivation medium. Cd, Pb, Cu, and Zn, in comparison with the control, also rapidly decreased, especially the content of chlorophyll-a and chlorophyll-b. However, for the production of pigments iron showed the same effect as for growth rate - with ramaining concentration the content of all chlorophyll types was also increased. For the highest iron concentration applied (10 micro g per L), a stimulatory effect on total chlorophyll and chlorophyll-a content was confirmed. The amounts of these pigments were increased for total chlorophyll by amount 12.8%, and for chlorophyll-a by about 79.6%
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