Polyethylene, Polystyrene, and Polypropylene leachate impact upon marine microalgae Dunaliella tertiolecta

In the aquatic environment, plastics may release several hazardous substances of severe ecotoxicological concern not covalently bound to the polymers. The aim of this study was to examine the adverse effects of leachates of different virgin polymers, polypropylene (PP), polyethylene (PE), and polystyrene (PS) on marine microalgae Dunaliella tertiolecta. The tests carried out on D. tertiolecta included: growth inhibition, oxidative stress (DCFH-DA), and DNA damage (COMET assay). Polypropylene and PS leachates produced growth inhibition at the lowest concentration (3.1% of leachate). In contrast, a hormesis phenomenon was observed with PE leachates. An algae inhibition growth ranking (PP>PS>PE) was noted, based upon EC₅₀ values. Reactive oxygen species (ROS) generated were increased with leachates concentrations with PS exhibiting the highest ROS levels, while a marked genotoxic effect (30%) was found only with PP. All leachates were free from detectable quantities of organic compounds (GC/MS) but showed the presence of transition, post-transition and alkaline earth metals, metalloids, and nonmetals (