Benzophenone-3 (oxybenzone) in zebrafish: histopathological and oxidative stress analysis

Benzophenone-3, commonly known as oxybenzone, is an organic compound widely used in sunscreens and personal care products for protection against UVA and UVB rays. Due to its environmental persistence and potential toxicity, this study evaluated the effects of BP-3 at an environmentally relevant concentration (1 µg/L) on the gills, kidney, and antioxidant system of zebrafish (Danio rerio).Adult male zebrafish were randomly distributed into three groups, each with three replicates (n = 10 per group): water control, solvent control, and 1 µg/L BP-3, using a static exposure system for 96 hours. After the experiment, histopathological analyses of the gills and kidneys were performed, along with biochemical assessments of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT).Exposure to BP-3 resulted in significant histopathological alterations in the gills, including vascular congestion, epithelial detachment, edoema, and lamellar aneurysm, indicating severe damage to respiratory function. In the kidneys, glomerular capillary dilation, tubular cell vacuolisation, and focal necrosis were observed, suggesting renal dysfunction. Biochemical analyses revealed impairment of the antioxidant defense system: in the gills, SOD activity decreased, while CAT remained unchanged, indicating oxidative stress accumulation. In the kidneys, SOD activity significantly increased, while CAT decreased, suggesting enzymatic imbalance and cumulative oxidative damage.These results demonstrate that BP-3, even at low concentrations, induces significant histopathological and biochemical alterations in the gills and kidneys of D. rerio, highlighting its potential to compromise organ function and antioxidant defences. These findings underscore the need for stricter regulation of BP-3 release into aquatic environments to mitigate its ecotoxicological impacts and protect aquatic biodiversity.