Woody and shrub plant phytoremediation of soils contaminated with heavy metal ions

Abstract

The use of woody and shrubby plants with a developed root system and a large biomass in the technology of phytoremediation of soils contaminated with heavy metals is analyzed. Woody plants can be used in the process of phyto-recovery of urban systems as long-term absorbers of heavy metal ions from the soil. The main mechanisms of phytoremediation of contaminated urban areas with the help of trees and shrubs are considered. The sorption capacity of cobalt, manganese and chromium ions by some species of woody and shrubby plants has been studied. The accumulation of heavy metals by seedlings under conditions of soil contamination with cobalt, manganese and chromium ions was studied. The transfer factor of cobalt, manganese and chromium ions was determined for the studied plant species. Species-hyperaccumulators of heavy metals, Gleditsia triacanthos L., Caragána arboréscens L., have been identified, which can be used for phytorestoration of soils of the technogenic region contaminated with cobalt, manganese and chromium ions. Low concentrations of cobalt, manganese and chromium were noted in the seedlings of Quercus robur L. and Robinia pseudoacacia L. in the aerial part, which indicates their ability to exclude heavy metal ions from their aerial parts. It has been established that seedlings of Gleditsia triacanthos L., Caragána arboréscens L., resistant to soil pollution, due to their excellent adaptability, even on degraded and contaminated with heavy metals soil of the experimental plot, have a high level of biomass accumulation without reliable facts of inhibition of growth processes. During the controlled process of phytoremediation carried out in the field, their high sorption capacity was noted, which makes it possible to recommend these species for use in technologies for the restoration of soils contaminated with heavy metal ions.