Bioaccumulation of Heavy Metals and Implications Associated with Consumption of the Thinlip Mullet (Liza ramada) Collected from Sites of Varying Salinity

Abstract

The bioaccumulation of heavy metals (Fe, Cu, Zn, Mn, Pb, Cd, Co, and Ni) were assessed in tissues (gills, liver, and muscles) of the thinlip mullet (Liza ramada) collected from three aquatic habitats varying in salinity in Egypt (freshwater, brackish, and offshore sites). In the freshwater site, metals accumulate in order of gills > liver > mussels with exception to Cu, Zn and Ni (liver > gills > mussels). In the brackish site, the order of metal accumulation for Fe, Cu, Zn, and Co were: liver > gills > mussels, and for Ni, Pb, and Mn were: gills > liver > mussels, while; Cd accumulated in order of mussels > gills > liver. In offshore site, Metals accumulates in order of: liver > gills > mussels except for Mn and Ni (gills > liver > mussels) and Cd (mussels > gills > liver).The overall metal concentrations for the three sites were ranked in the order of Fe > Mn > Zn > Cu > Pb > Cd > Co > Ni. There were significant differences between sites for Cu and Co, and between fish organs for Pb, Cd, Co, and Ni. Strong positive correlations were found between Fe and Zn (P<0.001), Fe and Pb (P<0.001), Fe and Mn (r= P<0.001), Mn and Ni (P<0.001), and Cd and Ni (r= P<0.01). Significant positive correlations (p<0.05) were observed between Zn with Co and Fe with Ni. Target hazard quotient (THQ) values for Pb, Cd, Co, and Ni were higher than 1 for the three sites, which suggests that adverse health effects might arise from the consumption of these fish. The estimated daily intake (EDI) values for Ni and Cd were higher than the recommended levels, indicating health effects; however, the values for rest of the metals were lower than the recommended EDI levels, suggesting that they are unlikely to pose a health risk.