METAL BIOACCUMULATION BY THE FRESH-WATER ALGA SCENEDESMUS-QUADRICAUDA

Bioaccumulation of six metals (Cu2+, Cu+, Mo6+, Mn2+ V5+, Ni2+) and th eir combinations by alga Scenedesmus quadricauda was determined by usi ng radio nuclide X-ray fluorescence (RXFA). The metals were added into the cultivation medium in concentrations corresponding with EC50 valu e for each metal. The obtained results indicate that Ni2+, Cu2+ and Cu + were accumulated in high amounts (20%, 17.5% and 15.19%) the Mo6+ io n (< 0.2%) was accumulated in the lowest amount. For metal-metal inter actions in accumulation of metal ions by alga S. quadricauda three typ es of answers were determined: inhibition (Mo-->Cu2+, Ni, Mn, V; V-->N i, Mn; Mn-->Ni, Cu2+, Cu+; Cu+-->Ni; Cu2+-->Ni; Ni-->Mn, V), enhanceme nt (V-->Cu+; Cu2+-->Mn; Cu+-->V, Mn; Mn-->V; Ni-->Cu2+, Cu+) and neutr al effect (V-->Mo; Cu2+-->Mo; Cu+-->Mo; Mn-->Mo; Ni-->Mo).