Bioaccumulation of Heavy Metals in Mackerel and Red Hybrid Tilapia Collected from Kijal and Paka, Terengganu, Malaysia

Abstract

The major goal of this study is to determine the bioaccumulation of heavy metals in the tissues and bones of Red Hybrid Tilapia <i>(Oreochromis niloticus)</i> and Mackerel <i>(Rastrelliger kanagurta)</i> taken from two distinct sites in Terengganu state, Malaysia, namely Kijal and Paka. Zinc (Zn), copper (Cu), nickel (Ni), and lead (Pb)were the metals examined. Soil analysis also was carried out for the same elements. The tissues and bones of the fishes were separated before further analysis was made. Drying process technique was used to determine the moisture content for all samples at 80 °C for 24 hours. Water content ranged between 70 & 77%. Triplicate samples were evaluated by using Atomic Absorption Spectrophotometer (AAS) to find out heavy metals concentration. Oven and Teflon beakers were used to fully digest all solid samples at 120 ^oC for 3 hours. Highest readings of Zn, Ni and Pb were found in the fish bone for the samples collected from both mentioned locations. However, different pattern was noticed for Cu where higher values were found in the tissues for the same samples. Values of Pb in the tissues were higher than the acceptable value in edible fish by Food and Agriculture Organization (FAO); 1 ppm and Malaysian Food Act (MFR) & World Health Organization (WHO); 2 ppm, whereas values of Cu, Zn were in the acceptable range set by the same organizations. No values recommended for Ni by MFR. In general heavy metals in the bones and tissues from both locations can be sorted in descending order as follows; Pb>Zn>Cu>Ni. Soil samples collected from both locations showed different pattern where high concentration was found for Zn followed by Pb then Cu and Ni. Moreover analysis for soil samples collected from Paka River showed higher content for all elements compared to Kijal. More investigation is needed to clarify whether this contamination is solely from industry or due to geology of the area.