Abstract: Objective To determine concentrations of a rsenic(As),beryllium(Be),chromium(Cr)and nickel(Ni)in maternal and umbilical cord blood and their influencing factors.Methods Totally 125 healthy pregnan twomen were selected as study subjects and 125 pairs of maternal and cord blood samples we re co llec ted.The microw ave digestion method was used to digest blood samples.The levels of As,Be,Cr and Ni in whole blood samples were determined with ICP-MS.Results Concentrations of As,Be,Cr and Ni in the maternls blood were 5.27,0.01,46.98,and 56.07μg/L,respectively and those concentrations in the cord blood were 3.81,0.01,49.74,and 41.74μg/L,respectively.Concentration of As in the cord blood was significantly lower than that of in the maternal blood(P<0.01).There were significant correlations in the concentrations of As,Be,Cr and Ni between the maternal and cord blood(P<0.01).The concentration of As in the maternal or cord blood corre lated significantly with exposure to occupational harmful factors and recen thouse decoration(P<0.05).Conclusion The pregnan twomen and fetus have exposed to As,Be,Cr and Ni during gestation.The concentrations of As,Be,Cr and Ni in the maternal blood a repositively correlated with that of in the cord blood.Be,Cr and Ni were not effectively barricaded by placenta.