Abstract: A total of 155 soil samples in the four regions (the west, the central, the east and the north) of Xining City were collected according to the random sampling method. The concentrations of heavy metals, As, Cr, Co, Cu, Pb, Sr and Zn were measured using the method of Xray fluorescence spectroscopy (XRF), and their potential ecological risk and health risk were evaluated. The results showed that the concentrations of heavy metals in this study were beyond the soil background values except As and Zn. The potential ecological risk index of the heavy metals in Xining City was moderate. The potential ecological risk was in order of Cr>As>Pb>Co>Sr>Cu>Zn. Among the four regions, the potential ecological risk level decreased as the north (39.7) > the central (33.3) > the east (31.5) > the west (30.6). According to the health risk index, hand to mouth contact was still the main pathway to posing human risk, and the heavy metals had a higher noncarcinogenic risk to children than to adults in any exposure pathway. The total noncarcinogenic risk to children in the four regions declined as the north > the central > the east > the west. Heavy metal Cr had the highest noncarcinogenic risk in all of the regions, especially in the north area, with high HI index exceeding the safety threshold value 1. Meanwhile, the order of carcinogenic risk index was the north > the east > the central > the west. In the north area, the carcinogenic risk index of Cr ranged from 10^-6-10^-4, which would pose possible carcinogenic risk to humans. Therefore, attention should be paid and the relevant measures should be taken.

Key words: regolith, earth road in loess area, runoff yield, sediment yield, simulated rainfall.