Urban highway runoff samples from seventeen rainfall events were collected in Shanghai in 2011. The concentrations of ten heavy metals and sixteen polycyclic aromatic hydrocarbons PAHs are analyzed. The results show that the heavy metal concentrations range within 0.50 to 51.80 As 0 to 20.80 Se 13.67 to 445.80 Zn 0 to 44.20 Pb 0 to 15.80 Ni 39.58 to 264.20 Fe 0 to 253.00 Mn 0 to 8.20 Cr 0 to 124.20 Cu and 159.83 to 536.40 μg/L Al . Se Pb Mn and Al concentrations in most samples exceed their corresponding criterion continuous concentrations CCCs while Zn and Cu concentrations exceed their criterion maximum concentrations CMCs .The concentrations ofΣPAHs range within 37.25 to 114.57 ng/L and concentrations of PAHs are all below their corresponding CCCs.Cu Zn and ΣPAHs show the first flush phenomenon. Analysis results of the modified Nemerow index method NIM indicate that runoff from eight rainfall events may have very strong biological toxicity effects four have strong effects three have moderate effects and only two have insignificant effects.Therefore it is concluded that urban highway runoff is a significant pollution source to aquatic ecosystems and needs immediate purification.
