Research on Geochemical Characteristics of Soil in a Chemical Industrial Factory Site in Jinan City

With the upgrade of urban industrial distribution, high pollution and energy-intensive companies were closed and moved. It is of great importance to investigate the geochemical characteristics of these abandoned soils for risk control of polluted sites. 100 soil samples at the site of a former chemical industrial factory in Jinan were collected and 42 indices, including concentration of total Cr, Cr(Ⅵ) and pH were analyzed to understand the geochemical characteristics of the site. Results show that total Cr concentration of the collected samples was 1025-2450 mg/kg and Cr(Ⅵ) concentration was 557.0-996.5 mg/kg (46.77% of the total Cr). At soil depth ranging from 0 to 80 cm, concentration change of total Cr and Cr(Ⅵ) was not significant. With the increase of soil depth, proportion of exchangeable Cr tended to decrease while residue Cr tended to increase. Total Cr concentration showed negative correlation with pH value while Cr(Ⅵ) did not show significant correlation with pH value. Cluster analysis demonstrated that the source of Cr in the site soil was different from that of other elements, which was mainly caused by the man-made pollution due to long-term heaps of chromium slag at the chemical plant. The other components had similar natural sources to the soil in the country and the Huang-Huai-Hai Plain.