Abstract: The investigation and evaluation of heavy metal and micro-element in soil indicated that the soil appeared heavy metal pollution and micro-element accumulation for protected vegetable in Hebei Province. Compared to the standard of envirnemt in base for no-pollution vegetable, the synthetic pollution index for heavy metal was 1.25 and it was polluted lightly. The individual pollution index was Cd>Cr>As>Pb. The index for Cd and Cr were 1.59 and 1.14 respectively, and both belonged to the third class. The index for Pb and As were 0. 05 and 0.35, and belonged to the first class and no pollution respectively. The ratio of exceeded standard for Cd and Cr were 73.7% and 68.4%. Compared to the background of Cd and Cr of soil in Hebei, the content of Pb and As were low. And the content of Cd and Cr were respectively twelve times and four times. The result showed that the soil micro-element took on accumulation in according to assessment standard of protected vegetable. The content of DTPA-Fe, DTPA-Mn, DTPA-Cu, DTPA-Zn were respectively 5.7 times, 2.9 times, 4.0 times and 15 times compared to farmland. In according to assessment standard, the ratio of high level for micro-element were indidually 65.8%, 25.1%, 100% and 83.6%. On the base of appraisal, it was analysed the source of heavy metal Cd was chemical fertilizer especially phosphorus fertilizer, the sources of micro-element Fe, Cu, Zn and Cr were dejeeta and organism fertilizer made of livestock and birds, litter and contamination without standard of limit for heavy metal content.

Key words: Protected vegetable, Soil pollution, Heavy metal, Micro-element

CLC Number: 

• S626