Limnetica 34

Currently, the presence of several pharmaceuticals and other organic compounds called ‘emerging’ contaminants has increased in water bodies. These compounds do not need to persist in the environment to cause negative effects because they are continuously introduced. Hence, assessing the effects of these compounds on aquatic ecosystems is essential. Therefore, the aim of the present study was to analyse the effects of several emerging contaminants (ibuprofen, atenolol, diclofenac and paracetamol) and benzene on Microcystis aeruginosa PCC7806 growth and toxicity. For this purpose, the growth of and intracellular microcystin concentration in M. aeruginosa PCC 7806 were measured in presence of the four emerging contaminants and benzene. The growth rate was estimated by chlorophyll a concentration, and no relevant changes were found. Changes in the expression of the operon mcy were examined by semi-quantitative RT-PCR. Intracellular microcystin production was determined using a MicroCystest® kit, and no changes were observed compared to control cells. Thus, the tested concentrations of the contaminants analysed in this study do not have a significant effect on microcystin production in this strain under laboratory conditions.