Genotoxic, metabolic, and biological responses of Chironomus sancticaroli Strixino & Strixino, 1981 (Diptera: Chironomidae) after exposure to BBP.

Benzyl butyl phthalate (BBP), which is widely used in industrial production, reaches the aquatic environment, mainly owing to improper disposal of plastic products. In the water, it remains adsorbed to sedimentary particles causing toxic effects in aquatic invertebrates such as Chironomidae, which are important in maintaining ecosystem dynamics and are an important link in the food chain. However, the effects of BBP on Chironomidae are still poorly known. Thus, the toxic effects of BBP on Chironomus sancticaroli at acute (48 h), subchronic (8 d), and chronic (25 d) exposures of concentrations between 0.1 and 2000 μg·L-1 were determined. Genotoxicity effects, changes in the oxidative stress pathway, and development and emergence of organisms were evaluated. Biochemical markers showed a reduction in cholinesterase (ChE) activity, indicating a neurotoxic effect on acute exposure (1-1000 μg·L-1). The antioxidant pathway, glutathione S-transferase (GST) activity showed reduction on acute (0.1; 1-2000 μg·L-1) and subchronic (1-2000 μg·L-1) exposures and reduction in superoxide dismutase (SOD) activity at all evaluated concentrations, suggesting oxidative stress. In contrast, lipid peroxidation was not observed. DNA damage occurred on acute (10 μg·L-1) and subchronic (10-2000 μg·L-1) exposures, indicating genotoxic effects. At concentrations above 10 μg·L-1, no emergence of adults occurred, while lower concentrations (0.1 and 1 μg·L-1) showed a reduction in the number of adults, mainly males. The observed effects indicate that BBP is genotoxic and causes biochemical alterations presenting high toxicity at the population level.