Uptake and depuration of polycyclic aromatic hydrocarbons from sediment by the zebrafish (Brachydanio rerio)

Zebrafish (Brachydanio rerio) were exposed for 30 d to individual C-14-labeled polycyclic aromatic hydrocarbons (PAHs) (anthracene, phenanthrene, pyrene, or benzo[a]pyrene) adsorbed on sediment. The uptake and depuration rate constants were measured. Rate of radioactivity release was measured under both contaminated (experiment 1) and clean (experiment 2) conditions. The results confirm that uptake and depuration rate constants were strongly related to physicochemical properties. However, the uptake from the water compartment was rapidly decreased in our microcosm system (-83% for anthracene and phenanthrene, -71% for pyrene, and -59% for benzo[a]pyrene within the first 2 d). For depuration in clean water, the half-lives of radioactivity loss from whole body were 63, 97, 115, and 138 h for anthracene, phenanthrene, pyrene, and benzo[a]pyrene, respectively, and were positively correlated with log K-ow. In experiment 1 after 10 d, the remaining PAH concentrations were only about 16% of the maximum concentrations measured at time 24 h for anthracene, 12% for phenanthrene, 30% for pyrene, and 46% for benzo[a]pyrene. K-ow appears to be a determining factor for partitioning constants for sorption to sediment, uptake, and release in aquatic organisms.