Journal of Ecology and Rural Environment ›› 2020, Vol. 36 ›› Issue (3): 273-280.doi: 10.19741/j.issn.1673-4831.2019.0165

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Humic Substances Amendments for Improving Phytoremediation of Heavy Metal Polluted Soils: A Review

HU Meng-ling, ZENG He-ping, DONG Da-cheng, LUO Yu, WANG Jin   

  1. Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650000, China
  • Received:2019-03-18 Online:2020-03-25 Published:2020-03-25

Abstract: Humic substances (HS) is widely used in agriculture and soil improvement as an important component of soil organic matter. Based on summarizing the effect and mechanism of HS on heavy metals in soil, the potential of phytoremediation of heavy metal pollution in soil was analyzed by literature investigation:(1) Macromolecule humin (HM) and humic acid (HA) could passivate heavy metal ions and reduce the toxicity of heavy metals to crops. However, smaller molecular-weight fulvic acid (FA) could promote the migration of heavy metals from the underground part to the upper part of the plant. (2) In addition to the physical and chemical properties of soil, the binding of HS with metal ions was mainly influenced by the ionic strength, molecular weight and the quantity of active functional groups and the pH of HS. (3) There are two methods of adding HS: foliar spraying and soil addition. Foliar spraying can inhibit the transport of heavy metals into plants and protect the photosynthetic system from heavy metals. Adding low concentration of HS in soil can promote the transport of heavy metals, but high concentration will have a negative effect on plants. (4) According to the ecotoxicological effects of the interaction of HS and heavy metals, the leaching effects of soil column and the growth development of plants, the secondary environmental risk caused by HS could be evaluated. Therefore, HS can be used as an environmental friendly phytoremediation enhancer to expand the application of phytoremediation in heavy metal contaminated soils.

Key words: humic substance, heavy metal, polluted soil, phytoremediation, application potential

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