关键词: 污染场地, 重金属, 形态, 土壤淋洗, 土壤修复

Abstract: Soil samples were collected from a heavily polluted area of an electroplating plant site for analysis of totals of the heavy metals therein and contents of their various forms separately in the soil.Furthermore,researches and screening were done to develop high-efficiency soil washing agents,of which comparison was made in effect of heavy mental removal rate.Results show that chromium (Cr) and nickel (Ni) were the most abundant heavy metals in the soil,reaching 1564.00 and 679.00 mg·kg^-1 respectively in total,and copper (Cu),zinc (Zn),and lead (Pb) was found to be 297.00,276.00 and 51.40 mg·kg^-1,respectively,of which 13.16%,28.08%,41.77%,21.50% and 31.18% was in available form,respectively.Among the six washing agents,i.e.deionized water,hydrochloric acid,acetic acid,oxalic acid,citric acid and EDTA,deionized water was was less effective in removing the 5 heavy metals while oxalic acid was more effective in removing Cu,Cr,Ni and Zn,reaching 55.1%,24.8%,47.5% and 29.3% in removing rate,citric acid was better at removing Cu,Cr,Ni and Zn,reaching 26.3%,25.7%,33.0% and 21.6%;and EDTA showed better performance on Cu,Ni,Zn and Pb,with removal rate being 31.5%,28.9%,21.4% and 30.6%,respectively.Taking into account comprehensively extraction effectiveness,water-solubility,easiness in operation and cost of the agents,it is suggested that citric acid be used with the optimal liquid to soil ratio being 10:1 and the optimal duration of washing being 6 hours.

Key words: polluted site, heavy metal, chemical form, soil washing, soil remediation