Seasonal variation of some heavy metals in the tissues of two important Marine Fish Species Epinephelus coioides and Euryglossa orientalis from Iraqi marine waters, north west arabian gulf

Abstract

Seasonal variations in the concentrations of six heavy metals (Cd, Cu,Mn, Ni, Pb and Zn) were determined in different tissues (muscles, livers , Ovaries , Intestines and gills) of Epinephelus coioides (serranidae) and Euryglossa orientalis from Al-Amiq port within National Iraqi Waters at Northern Arabian Gulf during the period October 2014 and November 2015. Heavy metals in fish samples were analyzed by atomic absorption spectrophotometry (AAS) after acid digestion. Two-way ANOVA statistics were used to compare the data among seasons, species, and organs (level of 0.05). the bioaccumulation of the heavy metals was species-related as the accumulations of the heavy metals analysed in the tested two fishes were of the following trend: Epinephelus coioides > Euryglossa orientalis. Accumulation of total heavy metals in Epinephelus coioides, the following order Zn > Cu > Cd > Mn > Ni > Pb is found, while that for Euryglossa orientalis, the following order: Cu > Zn > Mn > Cd > Ni > Pb is found. In the organs of Epinephelus coioides, heavy metals Cd, Cu, and Zn recorded the higher concentrations during summer season, high concentrations of Mn recorded during spring, and lower concentrations were recorded for Ni and Pb during all seasons. In the organs of Euryglossa orientalis higher concentrations of heavy metals were recorded for Cd during summer season, Cu during autumn season, Mn during spring season, Ni and Zn were low during all seasons, and Zn during winter season. The levels of Cd, Ni, and Zn in this study were higher than the maximum permissible limits (FAO, and WHO) for human consumption and that of Cu, Mn, and Pb are still lower.