ANDREW EKHATOR

Bisphenol A (BPA), a pervasive endocrine-disrupting chemical, poses significant ecological risks to aquatic organisms due to its widespread environmental contamination. This study investigates the effects of sublethal BPA concentrations on total protein levels in Clarias gariepinus (African catfish), a bioindicator species, to evaluate its sublethal toxicity and physiological implications. Following the organization for economic cooperation and development (OECD) guidelines for sublethal testing, fish were exposed to four BPA concentrations (1.25, 2.50, 5.0, and 10.0 mg/L) alongside positive (0.0 mg/L BPA) and negative (1.25 mg/L DMSO) controls under static conditions for 28 days. Total protein levels were quantified spectrophotometrically using the Biuret method, with statistical analysis performed via one-way ANOVA and Dunnett’s test (p < 0.05). Results revealed a significant dose-dependent reduction in total protein at higher concentrations (5.0 and 10.0 mg/L) after 7 days compared to controls (p< 0.05). However, these differences diminished by day 28, suggesting potential adaptive mechanisms or compensatory responses. The transient decline in protein levels at higher doses aligns with BPA-induced oxidative stress, which may impair hepatic protein synthesis or accelerate proteolysis. These findings underscore the time- and dose-dependent nature of BPA toxicity, highlighting its capacity to disrupt protein metabolism in aquatic organisms. The study emphasizes the need for stricter regulatory measures to mitigate BPA discharge into aquatic ecosystems, thereby reducing its sublethal impacts on fish physiology and broader ecological health.