Bioaccumulation of organochlorinated contaminants in three estuarine fish species (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), were 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 mullet and could be related to the higher lipid content of this species, Red mullet and sea bass exhibited a similar distribution pattern of these pollutants, whereas DDTs and HCB (hexaclorobenzene) were relatively more abundant in sea mullet, probably as a result of a direct uptake from the water lagoons from where the latter were collected and where these pollutants have been found in higher concentrations, A decrease in concentrations with size (age) was generally observed in red mullet 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 positive uptake by sea mullet was obtained, probably relating to the larger growth rate of this species, These results indicate that the accumulation of organochlorine compounds in coastal fish from the same area depends on lipid content, habitat, dietary intake, growth rate and the metabolism of each species. Although these fish can be used for pollution monitoring, the subsequent variability of pollutant body burdens that are influenced by these factors precludes the extrapolation of data from one species to another. (C) 1996 Elsevier Science Ltd