HEAVY METALS IN SEDIMENTS, WATER, SHRIMPS AND PERIWINKLE IN ESUK IBENO BEACH, IBENO, AKWA IBOM STATE NIGERIA

ABSTRACT The heavy metals (Cr, Cu, Pb, Cd, Ni and Fe) in sediments, water, shrimp (Parapenaeopsis atlantica) and periwinkle (Tympanostonus fuscatus) of Esuk Ibeno Beach, Ibeno, Akwa Ibom State, South East Nigeria were investigated using AAS spectrophotometer. The mean concentrations (mg/l) of Cr, Fe, Ni, Cu, Pb and Cd in sediments were 0.28±0.04%, 32.47±8.30%, 0.32±0.06%, 0.08±0.03 mg/L, 0.05±0.03 mg/L, and 0.01±0.01 mg/L respectively. The mean concentrations (mg/l) of Cr, Fe, Ni, Cu, Pb and Cd in water samples 0.67±0.08 mg/L, 1.05±0.13 mg/L, 0.46±0.09 mg/L, and 0.02±0.02 mg/L, 0.08±0.03 mg/L and 0.07±0.03 mg/L respectively. Except for Cr (1.00) and Cd (2.00), all other transfer factors in Tympanotonos fuscatus were below 1 indicating that there was no bio-magnification of the rest heavy metals but in Parapenaeopsis atlantica, Fe (8.38), Ni (1.39) and Cu (1.00) were biomagnified as they were the only investigated heavy metals above 1. The EXPdiet values recorded in this study are lower than the data for provisional tolerable daily intake for the investigated metals as suggested by the Joint FAO/WHO Expert Committee for Food Additives. Physicochemical analysis was carried out to determine the values of pH in sediments samples and also pH, turbidity, TDS, TSS, EC, and salinity for water samples. The THQ for all the investigated metals were less than unity. This indicates that there might be no considerable health hazard from the consumption of Parapenaeopsis atlantica and Tympanostus fuscatus from Esuk Ibeno Beach. The cumulative THQ (Hazard index) was less than one for both Parapenaeopsis atlantica and Tympanostus fuscatus. The HI value for Parapenaeopsis atlantica and Tympanostus fuscatus was 1.56 × 10-2 and 1.11 × 10-2 respectively. The results of Pearson’s correlation matrix showed that significant correlations were observed among variables at 0.05 levels. The results from this study showed that the contamination of water, sediment and biota (P. atlantica and T. fuscatus) of Esuk Ibeno River with heavy metals (Cd, Cu, Cr, Fe, Pb, and Ni) were largely from anthropogenic sources. The human health risk assessment showed that in this study, Expdiet of the investigated metals (Cr, Fe, Ni, Cu, Pb and Cd) were lower than the oral reference dose (RfD) suggesting that the heavy metals in shrimps and periwinkle tissues may not pose any health risk.