硫代硫酸铵添加对黄平大黄油菜富集土壤汞的影响-田间试验

在田间条件下,研究添加硫代硫酸铵对黄平大黄油菜(Brassica juncea var.HPDH)富集土壤汞(总汞含量13.7mg·kg-1)及土壤汞形态转化影响。试验设置2个处理,对照小区(无硫代硫酸铵)和处理小区(每公斤土壤加入8 g硫代硫酸铵),硫代硫酸铵溶液在植物收获前7 d添加到土壤。试验结束后,分析植物生物量和组织内汞含量。结果表明,硫代硫酸铵处理小区植物生物量(干重)要略高于对照区。硫代硫酸铵处理小区植物根系和地上部分汞含量分别是对照区的600和250倍。利用连续化学浸提法分析了修复前后土壤汞形态变化特征,发现硫代硫酸铵辅助植物修复后能显著降低土壤有机结合态汞含量,大幅度提高残渣态汞含量,溶解态与可交换态汞含量略有增加,特殊吸附态和铁锰氧化态汞含量无显著变化。

Effect of Ammonium Thiosulphate Addition on Mercury Accumulation by Brassica juncea var. HPDH- A Field Study

The current study was carried out to investigate the addition of ammonium thiosulphate on mercury accumulation by Brassica juncea var. HPDH and mercury fractionation transformation in soil (total Hg: 13.7 mg·kg^-1) under field condition. The two treatments including control plot (non-thiosulphate) and treated plot (ammonium thiosulphate was applied at a rate of 8 g·kg^-1 soil). The ammonium thiosulphate was applied at 7 days before the harvest of plant. The biomass and the mercury content in plants were analyzed after experiment. The results indicated that the dry biomass of the treated plant was higher than that of the control plant. The mercury concentrations in root and aboveground tissue of treated plant were nearly 600 and 250 times higher than that of the control plant. Mercury fractionation in soil was analyzed by the sequential extraction procedure (SEP) before and after remediation, and the result showed that the concentration of mercury associated with organic substance significantly decreased, while the concentration of mercury associated with residual fractions extensively increased, the concentration of mercury associated with soluble and exchangeable slightly increased. In addition, the concentration of mercury associated with specifically sorbed and Fe/Mn oxide bound fractions were relatively stable.