Reducing the concentration of toxic metals in the Litavka stream - evaluation of the remediation effectivity

High concentration of toxic metal in soil and in water is threat for all areas that are affected in such a way. It negatively influence ecosystems of the areas and it is dangerous for health and lives of people. A region of this characteristics is an area of former mining and smelting company in Březové Hory in Příbram. Contamination of soil, surface-water and underground water was caused by long-term mining of polymetallic ores that had been going since Medieval period. The smelting process also had significant influence. After the end of the mining and the related processes, it was necessary to deal with its negative impact to the region. The goal of this paper is to evaluate the effectiveness of measures which was realized as part of a remediation and redevelopment of the area. The reparative measures was aimed to decrease ecological risk in river Litavka and its surroundings. Leaching of toxic metals from rock environment by infiltration of atmospheric precipitation is the main source of pollution. The remediation and recultivation consisted of removal of buildings which belonged to former factory for processing of ores, including remediation and recultivation of this grounds and pile with mining waste from mine called Vojtěch and his forefield. New earth with appropriate physical and chemical characteristics, serving as water isolant, was found after reshaping of the pile. A postremediation monitoring was done to evaluate the quality of water in river Litavka and to prove accomplishment of targeted parameters and defined limits of the remediation. The monitoring included a collection of samples from surface-water and underground water, measurement of level of underground water and measurement of permeability of superficial layers of rock environment in defined monitoring points, so called control profiles. Based on original observation of the region and my participation during measurements, including collection of water samples, I could compare obtained information, evaluate the results of postremediation monitoring and make evaluation of effectiveness of the remediation and suitability of usage of the area. The results of the performed measures show that corrective steps successfully lowered the concentration of toxic metals in river Litavka and also the infiltration of precipitation into the underground water. The usage of the area as park is appropriate and is consistent with zoning