Ecotoxicological effects of new generation pollutants (nanoparticles, amoxicillin and white musk) on freshwater and marine phytoplankton species. (September 2021) - Broccoli, Andrea
Abstract: Phytoplankton occupies a key trophic level in aquatic ecosystems. Chemical impacts on these primary producers can disrupt the integrity of an entire ecosystem. Two freshwater ( Pseudokirchneriella subcapitata -Ps and Scenedesmus obliquus -S) and three marine ( Phaeodactylum tricornutum -P, Isochrysis galbana -I, Tetraselmis suecica -T) microalgae species were exposed to dilutions of four chemicals: nanoparticles (n-TiO2, n-ZnO), amoxicillin (antibiotic), and white musk (personal care fragrance) to determine the half maximal effective concentration (EC50 ) after 72 h of exposure under standardized and controlled environmental conditions. Cell cultures were exposed to EC50 to determine sublethal effects (72 h) based on biochemical (chlorophylls a, b, c ), molecular (changes in outer cell wall structure), and morphological alterations. We report for the first time EC50 values for nanoparticles in not standardized species (S, I and T) and for amoxicillin and white musk in all tested species. Standardized species (Ps and P) were less sensitive than non-standardized in some cases. Fourier-transformed infrared spectroscopy showed a marked spectral alteration (from 10.44% to 90.93%) of treated cultures compared to negative controls; however, principal component analysis disclosed no differences in molecular alteration between the five microalgae species or the two aquatic habitats considered. There was a significant decrease in chlorophylls content in all species exposed to EC50 compared to controls (Kruskal Wallis test; p < 0.05). There was a significant increase in cell-size (Mann–Whitney U test; p < 0.05) in I, P and T exposed to white musk and S exposed to amoxicillin. Findings highlight ecotoxicological risks from new generation pollutants for primary producers in aquatic ecosystems. Graphical abstract: Image 1 Highlights: Effects of new generation pollutants on five phytoplankton species were determined. EC50 values for amoxicillin and white musk were reported for the first time. μFT-IR showed a marked spectral alteration of treated cultures compared to controls. A significant decrease in chlorophylls in all species exposed to EC50 was observed. Changes in cell size, when significant, were an increase in maximum cell length.