Unveiling the multilevel impact of four water-soluble polymers on Daphnia magna: From proteome to behaviour (a case study)

The ubiquitous presence of water-soluble polymers (WSPs) in freshwater environments raises concerns regarding potential threats to aquatic organisms. This study investigated, for the first time, the effects of widely used WSPs -polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), and polyethylene glycol (PEG)- using a multi-level approach in the freshwater biological model Daphnia magna. This integrated assessment employed a suite of biomarkers, evaluation of swimming behaviour, and proteomic analysis to investigate the effects of three environmentally relevant concentrations (0.001, 0.5, and 1 mg/L) of the tested WSPs from molecular to organismal levels, assessing both acute and chronic effects. Our findings reveal that exposure to different WSPs induces specific responses at each biological level, with PEG being the only WSP inducing lethal effects at 0.5 mg/L. At the physiological level, although all WSPs impacted both swimming performance and heart rate of D. magna specimens, PAA exhibited the greatest effects on the measured behavioural parameters. Furthermore, proteomic analyses demonstrated altered protein profiles following exposure to all WSPs, with PVA emerging as the most effective Water-soluble polymers (WSPs) constitute a distinct class of synthetic polymers capable of dissolving in water. Despite their widespread use across various industrial and consumer applications, there remains a significant knowledge gap concerning their presence and impacts on ecosystems. Hence, this study focuses on evaluating the toxicity of four different WSPs -polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, and polyethylene glycol- at environmentally relevant concentrations of 0.001, 0.5, and 1 mg/L on Daphnia magna. The toxicity of WSPs was assessed at different levels of biological organization using an integrated approach encompassing biomarkers, behavioural parameters, and proteomics.