三种螯合剂对向日葵修复铀污染土壤的效应研究

Effect of Three Chelating Agents on U Polluted Soil Repairing by Sunflower

研究螯合剂对向日葵在铀污染土壤下的吸收、富集、转运特性具有重要意义。设置铀的浓度为150 mg/kg,同时分别投加2.5、5.0、7.5 mmol/kg的EDDS、CA和OA,研究了其对向日葵生长与吸收土壤中铀,以及对土壤中铀的活化性能的影响。结果表明:不同螯合剂处理均使向日葵的生物量降低,在高浓度螯合剂处理时,降幅最大;CA的添加比EDDS和OA更显著地增加了土壤铀的活化性,同时显著提高了向日葵的富集系数和转运能力;在7.5 mmol/kg CA处理下,向日葵的转运系数最高时为0.063,是对照组的1.42倍。此时,根系和地上部铀含量分别为178.95 mg/kg和11.27 mg/kg,是对照组的2.21和3.45倍;土壤中有效铀含量最大时为104.59 mg/kg,是对照组的1.63倍。各处理向日葵根系中的铀含量均高于地上部铀含量。综合看来,螯合剂的投加能有效活化土壤中的铀,促进植物转运、吸收。

To study the effect of chelating agent on absorption, accumulation and transport characteristics of sunflower under U contaminated soil is of certain significance. The concentration of U in soil was 150 mg/kg, added EDDS, CA and OA with the concentration of 2.5, 5.0 and 7.5 mmol/kg, and the effects on sunflower growth, U absorption and activation property of U in soil were investigated. The results showed that different treatments of chelating agents decreased the biomass of sunflower, and the decreasing degree reached the largest under high concentration of chelating agent; the addition of CA could increase available U concentration more significantly than EDDS and OA, at ability of sunflower were also enhanced; the maximum concentration was 7.5 mmol/kg, which was 1.42 times roots and overground part was 178.95 and 11.27 mg/kg, the same time, the enrichment coefficient and transport value of the transport coefficient was 0.063 when CA of that of CK. Under this concentration, U content of respectively, which was 2.21 and 3.45 times of that of CK. The maximum activating U content was 104.59 mg/kg, which was 1.63 times of that of CK, U concentration in roots was higher than that in overground part under all treatments. Therefore, proper addition of chelating agent could increase available U concentration in soil effeetively, and promote the absorption and transport of plant.