BIOACCUMULATION OF SOME HEAVY METALS IN SIGANUS RIVULATUS RELEVANT TO THEIR CONCENTRATION IN THE SURROUNDING MEDIA OF EL-MEX BAY, ALEXANDRIA, EGYPT
1Shehata S.M.; 1Ghanem M.H.; 1Abu-Zaid M.M.; 2Abdel-Halim A.M. and 1Abbas M.M.
1Biology Branch, Zoology Depart., Faculty of Science, Al-Azhar University, Cairo, Egypt.
2National Institute of Oceanography and Fisheries, Alexandria, Egypt.
The present study aimed to determine the heavy metals concentrations (cadmium, iron, lead and nickel) in the water and sediment and to investigate their accumulation in the target organs (gills, liver, muscles and skin) of Siganus rivulatus which collected from El-Mex Bay during the period from December, 2012 to November, 2013. Results revealed that, the average concentrations of heavy metals in the water and sediment were ordered as the following Fe > Pb > Ni > Cd. Iron (Fe) had the highest concentration in the water and sediment, while, cadmium was measured as the lowest one; being 22.33±6.25 μg/L & 1606±22.3 μg/g dry wt., respectively in the first element and 0.32±0.09 μg/L & 4.52±1.11 μg/g dry wt., respectively in the second one. Heavy metals were varied from season to another. The maximum values of cadmium, lead and nickel concentrations in the water were recorded during winter and the minimum levels were observed during summer. Moreover, iron ion concentration attained its high peak during spring and the lower one during summer. On the other hand, the maximum level of cadmium concentration in the sediment was recorded during winter and the minimum value was observed during summer. From another angle, iron, lead and nickel were peaked during autumn and declined during winter. The highest value of heavy metals in the different organs of S. rivulatus was detected for iron in the liver (371.90±84.80 μg/g wet wt) and the lowest one (0.11±0.06 μg/g wet wt) was observed for cadmium in the muscles. Bio-accumulation factor (BAF) in the different organs of S. rivulatus indicated that, muscles showed the lower bioaccumulation factor for cadmium and iron, however, gills had the minimal value for lead and the liver exhibited the same level of nickel. From another point of view, bio-sedimentation factor (BSF) of heavy metals in the different organs of S. rivulatus exhibited the same indications for the previous metals except nickel which showed the lower level of BSF in the liver and muscles. Statistical analysis for the metals concentrations in the water showed that, positive correlation between cadmium with iron, lead and nickel; iron with lead, nickel and lead with nickel. However, correlation coefficient between the different metals in sediment indicated a positive correlation in the case of interaction between iron with lead & nickel and the case of lead with nickel. Moreover, negative correlation was recorded in the case of interaction between cadmium with iron, lead and nickel. In the target organs, however, correlation coefficient between the different heavy metals in the water and different organs of S. rivulatus, collected from El-Mex Bay exhibited a strong positive correlation between metals and different organs. Generally, the excess of heavy metals lead to dangerous problem for human health, in the present study, accumulation of heavy metals in the fish muscles were within the safety permissible level for human use and have no threat to public health.
December 2013