Comparative toxicity of a brominated flame retardant (tetrabromobisphenol A) on microalgae with single and multi-species bioassays.

The potential threat of emerging chemicals to the aquatic flora is a major issue. The purpose of the study was to develop a multispecies microalgae test in order to determine the impact of species interactions on the cytoxicity of an emergent toxic contaminant: the tetrabromobisphenol A (TBBPA). Single and multi-species tests were thus performed to study the effects of this flame retardant on two microalgae (Pseudokirchneriella subcapitata and Nitzschia palea) commonly observed in freshwater.

Effects of a cationic PAMAM dendrimer on photosynthesis and ROS production of Chlamydomonas reinhardtii.

Poly(amidoamine) (PAMAM) dendrimers hold great promises for biomedicine. This study sought to examine the toxicity of generation 4 (G4) cationic PAMAM dendrimer to the green microalga, Chlamydomonas reinhardtii, using physiological and molecular biomarkers. Results revealed that the G4 dendrimer at 15 and 25 nM stimulated the photosynthetic process and the production of reactive oxygen species (ROS) in algae.

Monitoring of a flame retardant (tetrabromobisphenol A) toxicity on different microalgae assessed by flow cytometry.

Microalgae are key organisms in aquatic ecosystems. Emergent pollutants like the tetrabromobisphenol A (TBBPA) are potential threat for these primary producers at the base of the trophic chain. The effects of this flame retardant on three microalgae (Pseudokirchneriella subcapitata, Nitzschia palea and Chlamydomonas reinhardtii) commonly observed in freshwater ecosystems were studied using a flow cytometer.

Toxicity of PAMAM dendrimers to Chlamydomonas reinhardtii.

In recent decades, a new class of polymeric materials, PAMAM dendrimers, has attracted marked interest owing to their unique nanoscopic architecture and their hopeful perspectives in nanomedicine and therapeutics. However, the potential release of dendrimers into the aquatic environment raises the issue about their toxicity on aquatic organisms. Our investigation sought to estimate the toxicity of cationic PAMAM dendrimers on the green alga, Chlamydomonas reinhardtii.

Effects of pesticides on freshwater diatoms.

The study of pesticide effects on algae, and diatoms in particular, was focused on photosynthesis and biomass growth disturbances. Few studies have been performed to investigate the effects of these toxic agents on intracellular structures of diatom cells. Nuclear alterations and cell wall abnormalities were reported for diatoms exposed to toxic compounds.

Comparison between the polar organic chemical integrative sampler and the solid-phase extraction for estimating herbicide time-weighted average concentrations during a microcosm experiment.

Polar organic chemical integrative samplers (POCIS) were exposed for 9 days in two different microcosms that contained river waters spiked with deethylterbuthylazine, terbuthylazine and isoproturon. The experiment was performed with natural light and strong turbulence (flow velocities of about 15-50cms(-1)) for reproducing natural conditions. The concentrations were kept relatively constant in the first microcosm (2.