Ecotoxicological assessment of a sunscreen-derived pollutant, benzophenone-2, on freshwater fish (Labeo rohita)

Ultraviolet filters (UVFs) are constituents of skincare products that protect skin against UV ray damage, such as suntan, sunburn, and skin tumors. Due to their ability to biotransform, UVFs are considered emerging pollutants. Benzophenone-2 (BP-2), with a yellowish crystalline appearance, is one of the widely used UVFs in skincare products. It enters the aquatic environment by washing off the skin during swimming and recreational activities and becomes hazardous to aquatic life due to its lipophilicity and bioaccumulative potential. This study was designed to evaluate the acute and chronic toxicity of BP-2 for the freshwater fish Labeo rohita. For acute toxicity, fish were exposed to BP-2 concentrations from 0 to 10 mg/L with gradual increases to determine 96-h LC50, which was measured as 6.99 ± 0.37 mg L–1. To evaluate the chronic effects of BP-2 on the antioxidant enzyme system of different organs (in the gills, liver, kidney, muscle, and heart), fish were subjected to sublethal doses (⅓, ⅕, and ⅐ of LC50 of BP-2) for 35 days. Results indicate strong variations in superoxide dismutase (SOD) and catalase (CAT) activity in the treatment groups relative to the control group. Time-dependent increases in their activity during the first fortnight and then a gradual decline in their activity was observed for the remaining experimental duration. Changes in SOD and CAT activity in BP-2-exposed organs followed the order liver > gills > kidney > heart > muscle. Therefore, our results indicate that chronic exposure to BP-2 causes a decline in antioxidant enzyme activity in exposed organs, which is indicative of oxidative stress in the fish, validating its toxicity potential for aquatic life.