The Health Risk Assessment Of Heavy Metals In Multi-medium Of Minjiang River In Fuzhou Section

The study on the concentration of heavy metals in water,sediment and bivalve shellfish(Corbicula fluminea)frome Minjiang River in Fuzhou section has helpful to to know the current status of heavy metal pollution in Minjiang River.The health risk assessment and the potential ecological index provide basis for the treatments of the heavy metal pollution in water,sediment and benthos.Water,sediment and C.fluminea were collected in 9 sites from Minjiang River in Fuzhou setion.The concentration and modality of Fe,Mn,Zn,Cr,Cu,Cd,Pb,As had been analyzed,the evaluation of sediment by potential ecological index and health risk assessment of water and C.fluminea were made in Minjiang River.The results are as follows:(1)Fe,Mn,Cr,Cd,Pb in 9 sampling sites had different degree of out of limits,especially,the concentration of Cr even beyond the V level of water standard.The concentration of dissolved metals is greatly reduced after filtered,the quality of water improved significantly.(2)The concentration heavy metal of surface sediment in the order:Fe>Mn>Zn>Pb>As>Cr>Cu>Ni>Cd.Speciation of heavy metals in surface sediment showed that Fe and As were dominated mainly by the residual fraction,Mn was dominated by Fe-Mn oxides fraction.The geoaccumulation index indicated that there were no pollution in Fe,Cr,Cu,Ni basically,however the sediment was "strongly contaminated" in the case of Cd in S4,S7 sample sites,while for S3 and S8,it was"strongly to extremely contaminated".The most of stations fell in "moderately contaminated" or worse,except S9.The total potential ecological risk index in Minjiang River presented a low level,except S3 which was middle damage degree.(3)Fe,Zn,Mn showed significant negative correlation(r=-0.520,-0.871,-0.830)between body length and soft tissue,Cd,Cu,Cr showed positive correlation(r=0.645,0.586,0.777).the concentrations of As,Ni and Pb did not change significantly with the growth of body length.The enrichment of Fe,Cd,Mn,As was higher in shell,while Zn,Cu higher in tissue.The C.fluminea could enrich a variety of heavy metals,the enrichment factor in order:Zn>Cu>Cd>Ni>Pb>As>Cr>Mn.C.fluminea is a excellent bio-indicator of metal contamination.(4)Fe,Cu,Cr,Ni,Zn and Pb in sediment may be derived from natural sources,Mn and Cd may be derived from anthropogenic emissions,through spatial analysis,multivariate statistical analysis and modality analysis.Cd,Cu,Pb in C.fluminea probably come from industrial emissions,Cr and Fe may be from architecture,business,entertainment,Mn and As may be derived from natural sources.(5)The health risk assessment showed that the non-carcinogenic risk and carcinogenic risk were in the same order:baby>adults>teenagers>the elderly.The carcinogenic risk of As was greater than 10-4,so it posed toxicological risk of heavy metals when consumers ingest C.fluminea too much since CR was also beyond the recommended safety guidelines.