Humic Substances-Induced Changes in the Properties of Sb-Contaminated Soil and Effects on Sb Forms

Antimony (Sb) is a toxic environmental pollutant. Due to the human activities, the antimony pollution in soil is increasingly serious, and the soil antimony content is much higher than the normal background concentration in some antimony-contaminated areas. Humic substance plays an important role in soil improvement and contaminated remediation, but the selection of suitable humic substances application for remediation in Sb-contaminated soil is still limited. In order to investigate whether humic substances can be used to remediate Sb-contaminated soil, the humic substances including fulvic acid, humin, and humic acid were introduced into Sb-contaminated soil for 90 days of soil cultivation experiment. And changes in soil physicochemical properties and Sb forms were observed every 30 days. In the Sb-contaminated soil group with the addition of the three humic substances, the pH, soil organic matter, dissolved organic matter, available potassium, and effective phosphorus of Sb-contaminated soil increased in comparison with the blank group. In the experimental groups of humin and humic acid, the concentration of non-bioavailable states such the Sb residue state was raised with exogenous humic substance. Still the soluble state was more dramatically enhanced in the experimental group of fulvic acid. The results showed that in the fulvic acid experimental group, although the soil fertility was improved, the Sb in the soil was also activated, and the humin and humic acid experimental groups were able to blunt the active Sb in the soil. Therefore, this study could have important implications for the use of humic substance in the remediation of Sb-contaminated soils.