TOXICOKINETICS OF POLYCYCLIC AROMATIC HYDROCARBONS FROM CONTAMINATED SEDIMENT BY THE AMPHIBIAN LARVAE (PLEURODELES WALTL)

Abstract

The newt larvae (Pleurodeles waltl) stage 48–49 in the development table of Gallien and Durocher (1) were exposed for 30 days to sediment previously contaminated with individual ¹⁴C-labeled polycyclic aromatic hydrocarbons (PAHs), including anthracene (Ant), phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP). Toxicokinetic parameters (uptake and depuration rate constants) were measured. The rate of radioactivity release was measured under both contaminated (Experiment 1) and clean conditions (Experiment 2). The results confirmed that uptake and depuration rate constants were strongly related to physicochemical properties including the number of rings, molecular weight, octanol-water coefficient partition(K_OW), and water solubility. The highest uptake rate was observed with a low-molecular-weight compound (Ant). Comparatively the uptake rates for Phe, Pyr, and BaP were 17%, 48%, and 95% respectively, all lower than that for Ant. The rank order of PAH depuration rate constants from P. waltl was Phe > Ant > Pyr > BaP under both clean and contaminated conditions. The results also indicate that the depuration rate constants seemed to depend on the PAHs' bioavailability potential and their initial concentration in larvae at the beginning of the depuration phase. Thus when the initial concentration of pollutants in the animal were very weak (example: BaP), the depuration rate constants were in the same range for Experiments 1 and 2. In contrast when the PAHs' initial bioconcentrations were relatively high like for Ant, Phe, and BaP, their elimination from the larvae remained from 1.5-fold to 2-fold faster under Experiment 1 than under Experiment 2.

Keywords:

• amphibian larvae
• contaminated sediment
• polycyclic aromatic hydrocarbons
• toxicokinetics

Acknowledgments

This research was supported by the Department of Environment of the Petroleum Society Elf Aquitaine Production. The assistance provided by Ms. Blanche Alliance Djomo for preparation of the manuscript is also gratefully acknowledged.