Comparative Baseline Levels of Heavy Metals and Histopathological Notes in Fish Fromtwo Coastal Ecosystems of South-West of Spain

This work reports the comparative study of heavy metal water concentrations from two coastal ecosystems of Cadiz Gulf (SW Spain): Bay of Cadiz and Ria of Huelva estuary in samples taken on years 1999-2000. Sampling zones showed different heavy metal levels. Statistical analysis of dissolved trace metal concentrations (Cu, Zn, Cd and Pb) showed significant differences between Huelva and Cadiz zones based on the Cu level, with a marked seasonal factor and different metal sources (Industrial, geological, urban,...), observing a higher Cu concentration in Ria de Huelva respect to Bay of Cadiz. On the other hand, to evaluate the pollutant effects on aquatic biota, a histopathological analysis have been conducted in specimens of flat fish, Solea senegalensis from both zones. Lesions were more severe in fish from Ria of Huelva, being the most significant alterations: gill hyperplasia, fusion of secondary lamellae, disorganization of the hepatic parenchyma, cellular hypertrophy and vascular congestion in liver and tubular occlusion, loss of interstitial tissue and lipid-like vacuoles in kidney. Obtained results are useful as reference data for future environmental monitoring studies in these zones where to establish a heavy metal concentration temporal trend would be necessary.