Bioaccumulation And Health Risk Assessment Of Some Selected Heavymetals And Metalloids In Different Fish Species Of Hainan Island, China

In this study,the accumulation of twelve heavy metals(Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Se,Cd,Hg and Pb)in the muscles,liver,kidney,gills,skin and bones were determined in five different fishes(Tilapia fish,Nemipterus virgatus,Carassius auratus,Cyprinus carpio,and Trachinotus ovatus fish),collected from the coastal regions of Hainan island,located in the northern South China Sea.According to the results,the average concentrations of Fe,Cu,Zn,Cr,Mn,Se,Ni,As,Hg,Cd,Pb and Co in the fish tissues were 75.56 mg/kg,6.935 mg/kg,4.76 mg/kg,4.05mg/kg,3.298 mg/kg,0.981 mg/kg,0.732mg/kg,0.643 mg/kg,0.585 mg/kg,0.263 mg/kg,0.232 mg/kg and 0.08mg/kg respectively.Therefore,the hierarchy order of the metal concentrations in the observed fishes was Fe > Cu > Zn > Cr > Mn > Se > Ni > As> Hg> Cd > Pb > Co.So,from the results,it is confirmed that,in all fish samples,Iron(Fe)concentrations were highest among the observed heavy metals whereas Cobalt was accounted for the lowest concentrations.Findings of our study also revealed that the mean maximum Fe levels were present in the kidney of all fishes,followed by liver then gills.However,muscles and bones which are not active sites for bioaccumulation contained low concentration of Fe than kidney,liver and gills which are more metabolically active.It was found that highest concentrations of all the twelve metals tended to appear in benthic and dermesal fish living in bottom layaers of aquatic environment.While least concentrations of heavy metals were found in pelagic fishes living in upper layars of aquatic environment.Integrating concentrations of the twelve heavy metals following the order,metals in benthic fish > metals in demersal fish > metals in pelagic fish.Statistical Correlations was found to be significant at a significance level p < 0.01(2-tailed).The THQ values of of Hg,Zn,Mn,Ni,Pb,Fe,Co,Cu,Se and Cd were all less than 1 suggesting that presence of these metals in tissues of the different fish species of Hainan Island.It means these metals may not pose any serious human health risk after consumption.However,the THQ values of Cr and estimated inorganic As were larger than 1,which indicated that Cr and As would cause potential non-carcinogenic risk for human health consumer.As fish is an important part of human diet,it is necessary that biological monitoring of the water and fish meant for consumption should be done regularly to ensure continuous safety of the seafood.Further research studies has been recommended on the effects of heavy metal toxicity in the affected fish to assess the potential risk to human health associated with the consumption of such affected fish.