Survey and evaluation of heavy metal contamination of soils and vegetables in Nanning

The contents of heavy metal ( Pd, Cd, Cr, As, Hg ) in the soil, the irrigation water and the vegetables in the main vegetable production area in Nanning, including Wuming and Yongning, were examined and analyzed to evaluate the status of heavy metal contamination. The evaluation of the soil was by the means of single pollution index, the vegetables by terms of the standard of pollutionfree vegetable, and the irrigation water by the standard of irrigation water formulated by the state. The results showed that the soil were polluted in various degrees by heavy metals, in the order of CdCr PdAsHg. The contents of heavy metals in fairly portion of the vegetables exceeded the State's standard, but there were only one or two indexos of the contents exceeded the State's standard in the irrigation water.