The sensitivity of biotests basec on the algae chlorella and scenedesmus to heavy metals
The toxic effect of cadmium, zinc and copper ions on growth and sensitivity of algae Scenedesmus quadricauda (Turp.) Breb. and Chlorella vulgaris Beijer was examined. Both cultures are widely used in the Russian Federation as test-organisms for water toxicity bioassay. Chlorella was cultured in 50% Tamiya medium in cultivator KV-05 at 36°C. Chlorella growth inhibition test was conducted in the cultivator KVM-05 during 22 hours at 36°C in Uspenskii, Prat and 2% Tamiya media. Alga Scenedesmus was cultured in 10% Tamiya medium in cultivator KV-05 at 20°C under continuous illumination. Scenedesmus growth inhibition test was conducted in devices UER-03 in Uspenskii, Prat and 1% Tamiya media at 25°C. Due to the rotation of the cassette with the water samples and test organisms these devices provide equal temperature, light conditions and aeration. During cultivation (45 hours), the number of cells in control increased by 20-25 times. It was shown, that growth of both test-cultures practically did not differ when Prat, Uspenskii and 1-2% Tamia media were used. At the same time the degree of growth inhibition of both algae cultures in presence of heavy metals was within the range of 20-30%. Good likeness of the sensitivity of these bioassays indicates the possibility of their application, without opposing them to each other.