Combined effects of nanoplastics and temperature on behavioral and biomarker responses in Zebrafish (Danio rerio)

In recent years, there has been an increase in scientific investigations on the effects of emerging environmental contaminants on aquatic biota, including pharmaceuticals and plastic particles. Plastic litter introduced into the environment undergo disintegration processes that generate incredibly small particles, called micro (< 5 mm) and nanoplastics (NP, < 100 nm). These fragments represent a threat to aquatic organisms health, and can result in the depletion of energy reserves, metabolic changes and neurotoxic effects in bivalves and fish. Recent studies showed that personality can play a determinant role on animals survival under stressful conditions, but whether and how this behavioral trait is influenced by environmental contaminants is yet unknown. The present work carried out using adults Danio rerio, aims to provide data to answer the following questions: what are the consequences of prolonged exposure to nanoplastics and what role does personality play? Are effects modulated by temperature? The experiment evaluated feeding, swimming performance after 7, 12, and 15 days of exposure to two concentrations of polystyrene NP (20 µg/L and 200 µ/L) at 25ºC and 30 ºC. Biochemical (AChE, sugars, lipids) and cytogenetic markers (erythrocytic nuclear abnormalities) were also measured at 15 days exposure. PERMANOVA analyses on feeding showed a significant interaction of the effect personality per treatment (P < 0.05); significant response occurred in swimming performances as a result of the combination of factors personality and treatment and temperature and treatment. Influence of nanoplastics showed statistical significance also in the investigation of lipids and cytogenetic effects. Overall, data showed that the interaction of the personality with the concentrations of nanoplastics (and the different temperatures) would open to the possibility that different personalities could react differently (or been influenced differently) from the same NP concentration.