Innovative technological solution is oriented in solving the problem of heavily polluted urban areas with potentially toxic metals.
Residents of contaminated areas are exposed to toxic metals primarily through direct entry of contaminated particles into digestive system, including by ingestion of food grown in contaminated soil and inhalation of contaminated dust particles. Since the soil is today often considered as the primary source of pollutants in the environment, the remediation of soil is an urgent measure to achieve sustainable impact of rehabilitation. Selection of remediation technology depends on the characteristics of pollutants, type of soil and land use. Before the selection of the remediation technology, it is necessary to carry out feasibility tests of individual technology to achieve the best ratio of efficiency, economic and ecological acceptability.
In the field of remediation of toxic metals, especially with lead contaminated soil, the following technologies are known and used:
- Solidification and stabilization of the metals is a method in which materials such as phosphate, cement, lime or different sulphides are admixed and/or injected into the soil. Metals are not removed from the soil, however, their bio – availability is reduced.
- Phytoextraction of pollutants from the soil exploits the ability of plants to accumulate metals in the aboveground plant parts. However, species with sufficient biomass and accumulation of sufficient quantities of lead are not known yet.
- Soil washing, which removes metals from the soil by mechanical operations on the principle of separation. Here, the fractions of the soil, in which the metals are mainly bound, are removed. By this, organic matter and fine silt particles are mainly removed. In the case of soil from Meža valley, over 20 % of the soil particles would be removed by this method due to high content of organic matter in the soil. This would result in the loss of the soil function as a plant substrate.
- Soil washing with solutions such as salts, acids and chelating agents is the only technology for the removal of toxic metals, especially lead from the soil. The most effective approach is to use ligands that form water-soluble metal complexes that can be transferred from the solids into the liquid form. This usually results in a huge quantity of contaminated process solution. The most used ligand is ethylenediamine tetraacetate (EDTA).