腐植酸钾对土壤铅化学形态、生物可给性及健康风险的影响

Effect of Potassium Humate on Chemical Fractionation,Bioaccessibility and the Health Risk Assessment of Lead(Pb) in Soil

通过重金属分级提取和生物可给性体外模拟试验,研究了腐植酸钾对污染土壤中铅化学形态组成、生物可给性及基于生物可给性的健康风险评价的影响。结果表明,不同比例的腐植酸钾均可显著提高铅污染土壤的pH值和有机质含量,且随着添加量的增大而升高;添加腐植酸钾可显著降低土壤中弱酸提取态铅和可还原态铅含量,增加可氧化态铅和残渣态铅含量,其影响随添加量的增大而增强;土壤中铅的生物可给性随腐植酸钾添加量的增加而显著降低;基于生物可给性的人体健康风险评价显示,经口摄入铅污染土壤造成的危害水平随着腐植酸钾添加量的增大而显著降低,且儿童危害商(非致癌风险)高于成人,约为成人的1.8倍;土壤中铅的安全含量限值随腐植酸钾添加量的增大而增大,非敏感用地高于敏感用地。研究表明,腐植酸钾可有效降低铅污染土壤中铅的健康风险和生态风险,可用于铅污染土壤的修复。

Effect of potassium humate on fractionation, bioaccessibility and the health risk assessment of lead（Pb） in soil were explored by the sequential extraction procedure and bioaccessibility in vitro simulation experiments. Results showed that the pH and the organic matter content in Pb contaminated soil increased significantly with the increase of potassium humate ratio. Potassium humate could significantly decrease acid extractable Pb and reducible Pb content in soil, and increase oxidation state Pb and residue Pb content, with the increase of additive proportion increasing of potassium humate, the effect became strong. Soil Pb bioaccessibility decreased significantly with the increasing of potassium humate. Human health risk assessment based on bioaccessibility revealed that hazard level via oral intake of Pb polluted soil decreased significantly with the increasing of potassium humate, Children hazard quotient（non carcinogenic risk） was 1.8 times than that of the adult. Soil Pb security limit content was increasing along with the increasing of potassium humate, while non sensitive land was higher ＇than that of the sensitive land. These results indicated that the application of potassium humate could effectively reduce the health risk and ecological risk of Pb in soil, and could be used to rehabilitate Pb contaminated soil.