The uptake metabolism and biological half-life of benzo[a]pyrene in different tissues of sea bass, Dicentrarchus labrax.

The disposition of polycyclic aromatic hydrocarbons in aquatic organisms is of interest from the viewpoint of both animal and human health. The kinetics of uptake and metabolism of benzo[a]pyrene (BaP) were studied in various tissues of the marine fish, sea bass, upon intraperitoneal injection of the compound. A decrease in radioactivity occurred in all tissues and the calculated half-lives were 12.4 days for fat, 6.5 for kidney, 5.1 for intestine, 4.8 for gallbladder, 4.5 for spleen, 2.9 for muscle, 2.4 for whole body, 2.3 for gonads, 2.3 for gills, and 2.2 for liver. The kinetics of distribution of radioactivity between alkali and hexane tissue extracts were determined in order to assess the overall metabolic potential of various organs. The liver, intestine, gills, and kidney displayed a relatively high metabolic potential in comparison with the spleen, muscle, gonads, and fat. The significance of the observations with respect to understanding mechanisms of toxicity is briefly discussed. Attention is specifically drawn to the presence of a fairly active metabolism or metabolite redistribution system in the muscle and the potential for exposure of blood cells to metabolites via hydrocarbon transformation processes in the spleen. This in vivo study, in which hydrocarbon disposition was studied in various tissues, also supports the hypothesis that polycyclic aromatic hydrocarbons should not bioaccumulate to any significant degree in fish and that exposure of humans to such compounds through the consumption of fish products can be expected to be minimal.