Characteristics and Ecological Risk Assessment of Pollutants in the Intertidal Surface Sediments of Sansha Bay,Fuj ian

CHEN Qiang; YAN Xizhu; WANG Song; LI Yuanrong

Abstract：Information about the intertidal surface sediments of Sansha Bay was limited.In order to pro-vide new theoretical evidence for ecological restoration of the intertidal surface sediments in Sansha Bay,concentrations of heavy metals(Cu,Pb,Zn,Cd,Cr,Hg,and As),nonmetal pollutants (organic carbon,sulfides,oil,total nitrogen,total phosphorus)and value of oxidation-reduction potential (Eh),pH were examined using correlation analysis.The potential ecological risk of pollutants in San-sha Bay was also assessed based on the single factor pollution index,Nemerow integrated pollution in-dex and potential ecological risk index.The results indicated that average concentrations of Cu,Pb,Zn, Cd,Cr,Hg,and As were 20.9mg/kg,49.9mg/kg,110.4mg/kg,0.136mg/kg,46.6mg/kg,0.028 mg/kg,6.64mg/kg,respectively;and average concentrations of oil,sulfides,organic carbon,total phosphorus,total nitrogen were 36.5mg/Kg,38.4mg/Kg,0.76%,0.42%,0.12%,respectively;Eh value ranged from -178mv to 171mv (mean:-56.4mv);pH value ranged from 6.74to 7.06(mean:6.91).No high positive linear correlations occurred among concentrations of heavy metals except for Cu,and Zn (P<0.05).Except for the significant correlations of Cu,and organic carbon,total nitro-gen,Zn,and total nitrogen,Hg,and oil (P<0.05),there were insignificant relationships between all the other heavy metals and nonmetal pollutants.Insignificant relationships occurred among concentra-tions of nonmetal pollutants (P(0.05).Eh had a significant correlation with sulfides (P<0.05).The sequence of single factor pollution index was Pb(2.00)>Zn(1.38)>Cr(0.78)>Cu(0.70)>As(0.44)>Cd(0.27)>Hg(0.14).The Nemerow integrated pollution index of heavy metals was 1.53,which was at the intermediate pollution level.The potential ecological risk index of heavy metals was 34.51, which posed a low potential ecological risk and had a low probability of being associated with adverse bi-ological effects.The degree of their potential ecological risks was in the order:Pb(9.98)> Cd(8.16)>Hg(5.52)> As(4.43)> Cu(3.49)>Cr(1.55)> Zn(1.38).there were two kinds of the nonmetal pollutants (Tp,TN)exceeding the standards in the tidal flat .