Cadmium bioaccumulation in three benthic fish species, Salaria basilisca, Zosterisessor ophiocephalus and Solea vulgaris collected from the Gulf of Gabes in Tunisia.

To select a marine teleost fish which can be used as a bioindicator of cadmium (Cd) pollution in the Gulf of Gabes in Tunisia, Cd concentrations in liver and gill were compared in three benthic fish species including Salaria basilisca, Zosterisessor ophiocephalus and Solea vulgaris. Fish samples were collected from three selected sites in the Gulf of Gabes, with different degrees of Cd contamination: the industrialized coast of Sfax (S1), the coast of Douar Chatt (S2) and the coast of Luza (S3). The results shows that Cd concentrations in both sediment and water collected from S1 were significantly higher (p < 0.0001) than those from S2 and S3. For each species, Cd concentrations, in both liver and gill, showed the decreasing order: S1 > S2 > S3. The highest concentration of Cd was detected in the liver of S. basilisca, and only S. basilisca showed bioaccumulation factors (BAF) greater than 1 in all studied sites. In S1 and S2, BAF values respect the following order: S. basilisca > Z. ophiocephalus > S. vulgaris. These results of significant bioaccumulation of Cd, in terms of hepatic concentrations and bioaccumulation factors, indicated that S. basilisca can be used as bioindicator to evaluate the evolution of Cd pollution in the Gulf of Gabes.

Association of spinal deformities with heavy metal bioaccumulation in natural populations of grass goby, Zosterisessor ophiocephalus Pallas, 1811 from the Gulf of Gabès (Tunisia).

The present study illustrates an analysis of spinal deformities associated with metal accumulation in natural populations of Zosterisessor ophiocephalus derived from polluted (S1) and unpolluted (S2) areas in the Gulf of Gabès in Tunisia. Three basic types of spinal deformities were detected: kyphosis, scoliosis and lordosis. These basic deformities frequently co-occur. Spinal deformities were observed in 10.72% of the total examined fish (n = 494). Deformed fish were 3.85 times more frequent in S1 than in S2. In both sexes, the highest occurrence of deformities was observed in the 111-120 mm class decreasing thereafter with fish length. Hepatic concentrations of cadmium (Cd), copper (Cu) and zinc (Zn) were significantly higher in Z. ophiocephalus from S1 than those from S2. Comparisons between fish in each site showed that liver concentrations of Cd and Zn were significantly higher in deformed fish than in normal fish. The relationship between metals accumulation and observed spinal deformities as well as the suitability of this kind of studies for environmental monitoring are discussed.