Evaluation of the toxicity of an oil spill conducted through bioassays using the fish Solea senegalensis

The toxicity produced by fuel pollutants was evaluated through bioassays using the Senegalese sole Solea senegalensis. Juveniles were exposed for 21 days to different dilutions obtained by mixing fuel extracted from the Prestige oil tanker and sediment from a clean area of Cádiz Bay. After the exposure period, three biomarkers were analyzed (7-ethoxyresorufin-Odeethylase [EROD], glutathione S-transferase [GST], and glutathione reductase [GR] enzymatic activity), as well as the histopathology of two of the main target organs (gills and liver). Significant (P < 0.05) biomarker inductions were observed in the exposed fish analyzed on day 21 relative to the control group (day zero). Lesions were detected in both organs studied, but the liver was the most affected. The frequency of appearance of the lesions was greater in the samples containing higher concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals. The results showed significant correlations between the total PAH concentrations and GST, GR, and EROD enzymatic activity, with correlation coefficients of R = 0.96 for GST, R = 0.82 for GR, and R = 0.60 for EROD.