Abstract

The level of four heavy metals cadmium (Cd), copper (Cu), lead (Pb) and mercury (Hg) in flesh of Tinca tinca and Pelecus cultratus as well as water samples (90 each) collected from six different sites of southern Caspian Sea were evaluated. The results of this study revealed that the mean Cd, Cu, Pb and Hg levels in the water samples was significantly lower (P< 0.05) than the mean residuals levels in flesh of T. tinca and P. cultratussamples. The mean residuals levels of Cd were 0.60, 0.77 and 0.54 ppm/wet weight for T. tinca , P. cultratus and water, respectively. 11.1% of T. tinca, 18.6% of P. cultratus and 10.4% of water samples had Cd residuals level exceeding the permissible limit. The mean residual levels of Cu were 1.76, 1.94 and 1.28 ppm/wet weight for T. tinca, P. cultratus and water, respectively. Cu residuals levels in all T. tinca and P. cultratus sample were within the action limit, while 6.4% of water samples exceeded the action limit. Meanwhile, the mean residuals level of Pb was 1.51, 1.74 and 1.12 ppm/wet weight for T. tinca, P. cultratus and water, respectively. 20.5% of T. tinca, 36% of P. cultratus and 28.9% of water samples had Pb residuals level exceeded the permissible limit. The mean residuals levels of Hg were 0.34, 0.17 and 0.08 ppm/wet weight for T. tinca, P. cultratus and water, respectively. 5.1% of T. tinca, 13% of P. cultratus and 9.2% of water samples had Hg residuals levels exceeding the permissible limit. These findings recommend that improved water quality control and periodically environmental monitoring are necessary in Caspian Sea. In addition, recommendations regarding the acceptable number of fish meals to be consumed weekly from the health authorities should be taken to fish consumers, especially children and pregnant woman, to control the accumulative effect of heavy metals.

Key words: Heavy metals, fish tissue, Caspian Sea, pollution, water.