Selection and sensitivity comparisons of algal species for toxicity testing

The sensitivity of 7 algal species representing the green and blue green al gae was evaluated using EC50 values from the toxicity tests on 3 metal comp ounds (K2Cr2O7, CuSO4. 5H(2)O, ZnSO4) and 3 formulated products of herbicid es (oxyfluorphene, pendimethaline, atrazine). The growth inhibition tests w ere conducted in microplates. The variability in sensitivity was as high as 5 orders of magnitude (oxyfluorphene). The principal component analysis se parated the cyanobacterial strain (Synechococcus leopoliensis) from the res t of algae representing Chlorophyta. The green algae were divided into two groups: first group with minute species (Chlorella kessleri and Stichococcu s bacillaris) tolerant to herbicides and second group with the most sensiti ve species: Raphidocelis subcapitata (commonly known under synonym Selenast rum capricornuium), Scenedesmus guadricauda, Scenedesmus subspicatus and Ch lamydomonas reinhardtii). The differences in sensitivity among the species of the second group were not distinctive. Therefore, any of these species, because of their similar sensitivity, can be recommended as test organisms in the single algal assays. However, toxicity results showed that none of t hese species can represent all the phylogenetic (taxonomic) groups of algae . (C) 1999 Elsevier Science Ltd. All rights reserved.