Benzo(a)pyrene (B[a]P) is a pervasive freshwater pollutant, yet its toxicity to the fish gallbladder remains poorly understood. This study investigated the toxicological impacts of 2.5 and 25 μg/L B[a]P on common carp (Cyprinus carpio) using histological, transcriptomic, and single-cell RNA sequencing (scRNA-seq) analyses. Results showed that the gallbladder is a primary site for B[a]P accumulation. High B[a]P concentrations c...