POTENTIAL ECOLOGICAL RISK AND CONTAMINATION OF HEAVY METALS IN FENG RIVER, CHINA

The new Xi'an-Xianyang national district is one of the 16 new national districts in the Shan'Xi Province. Determining and analyzing the water environment quality in the area can provide scientific basis for area planning. Twenty sediments at 5 km along the Urban Feng River were collected, and the concentration of six heavy metals (As, Cr, Cu, Ni, Pb, and Zn) were analyzed by wavelength dispersive X-ray fluorescence spectrometry. Results indicate that the concentration scales of As, Cr, Cu, Ni, Pb, and Zn in the sediments are 0.4-34.3, 48.3-152.4, 0.6-24.3, 7.4-34.1, 13-32, and 13-30.7 mg.kg(-1), respectively. The mean concentrations in the sediments are 6.47, 105.73, 13.75, 21.59, 23.48, and 26.76 mg.kg(-1), respectively. According to the H (a) over circle kanson potential ecological risk index and enrichment factor index, these heavy metals present low potential ecological risk in all sites (E-f(i) < 40). The mean enrichment value of Cr is 1.83, whereas the mean enrichment values of As, Cu, Ni, Pb, and Zn are 0.58, 0.59, 0.77, 0.97, and 0.37, respectively.Cr presents minor enrichment, which may originate mainly from waste discharge, especially from mining, machinery, and agricultural activities. By contrast, As, Cu, Ni, Pb, and Zn are not enriched and may originate from natural weathering processes. The results can provide a scientific basis for water environment improvement and city planning of the area.