BIOACCUMULATION OF ORGANOCHLORINATED CONTAMINANTS IN 3 ESTUARINE FISHSPECIES (MULLUS-BARBATUS, MUGIL-CEPHALUS AND DICENTRARCUS-LABRAX)

The bioaccumulation of organochlorinated contaminants (DDTs, PCBs and HCB) in three representative fish species from the Ebro Delta (western Mediterranean) was studied. The species, red mullet (Mullus barbatus) , sea mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax), wer e selected for their characteristic habitats and feeding behaviours to investigate their potential as bioindicators in pollution monitoring studies, Higher levels of PCBs and DDTs were generally found in red mu llet and could be related to the higher lipid content of this species, Red mullet and sea bass exhibited a similar distribution pattern of t hese pollutants, whereas DDTs and HCB (hexaclorobenzene) were relative ly more abundant in sea mullet, probably as a result of a direct uptak e from the water lagoons from where the latter were collected and wher e these pollutants have been found in higher concentrations, A decreas e in concentrations with size (age) was generally observed in red mull et and sea bass, though less clearly in sea mullet. This decrease was more pronounced for DDTs, probably owing to metabolic transformations, However, when data were normalized to lipid content, evidence for a p ositive uptake by sea mullet was obtained, probably relating to the la rger growth rate of this species, These results indicate that the accu mulation of organochlorine compounds in coastal fish from the same are a depends on lipid content, habitat, dietary intake, growth rate and t he metabolism of each species. Although these fish can be used for pol lution monitoring, the subsequent variability of pollutant body burden s that are influenced by these factors precludes the extrapolation of data from one species to another. (C) 1996 Elsevier Science Ltd