Evaluating the Toxic Effects of Nanoplastics on Cirrhinus mrigala: Behavioral Alterations, Mortality, and Histopathological Changes

Abstract

Nanoplastics are increasingly recognized as emerging aquatic pollutants with the potential to disrupt fish health at behavioral and physiological levels. This study evaluated the toxicological effects of polystyrene nanoplastics (PS-NPs) on Cirrhinus mrigala, focusing on changes in behavior, survival, and organ condition. A total of 150 fish were randomly allocated into three equal groups: a control group and two treatment groups exposed to PS-NPs at concentrations of 1 mg/L and 10 mg/L, respectively. Exposure was conducted over a four-week period, five days per week. Throughout the study, fish were monitored for changes in swimming behavior, feeding activity, and mortality. Organ samples were collected post-exposure for gross anatomical examination under a microscope. One-way ANOVA revealed a statistically significant difference in survival among groups with the highest mortality observed in the 10 mg/L group. No substantial behavioral abnormalities were observed across the groups, although the 1 mg/L group experienced a sudden mortality event early in the trial. Mild lesions and discoloration were observed in the organs of exposed fish, particularly at higher concentration. These results suggest that while PS-NPs did not elicit pronounced behavioral disturbances in Cirrhinus mrigala, they did cause observable physiological stress and increased mortality in a dose-dependent manner.