Toxic effects of polystyrene nanoplastics on microalgae Chlorella vulgaris: Changes in biomass, photosynthetic pigments and morphology

Presence of nanoplastics within aqueous media has raised concerns about their adverse impacts on aquatic organisms. This study evaluated toxic effects of amino-functionalized polystyrene nanoplastics (PS–NH2) with diameters of 90 (PS–NH2-90), 200 (PS–NH2-200) and 300 (PS–NH2-300) nm on green microalgae Chlorella vulgaris. A dose-dependent toxicity response by PS-NH2-90 and/or PS-NH2-200 on biomass and photosynthetic pigment (chlorophyll a) end-points of C. vulgaris was observed. Whereas varied concentrations of PS-NH2-300 had no significant toxic effect on biomass and chlorophyll a end-points compared to control groups (p > 0.05). A comparison of toxicity of similar concentrations of PS-NH2-90, PS-NH2-200 and PS-NH2-300 showed small-sized PS-NH2 were more toxic than large-sized PS-NH2 (toxicity of PS-NH2 increased in the order PS-NH2-300