MERCURY TOXICITY OF SEDIMENTS IN MINING-AFFECTED AREA RUDIANY (SLOVAKIA)

Ecotoxicological tests have been successfully applied to monitor the contamination and bioremediation efficiencies of soils and these tests are important in the ecological assessment of hazardous waste sites and in supporting management decisions for subsequent remediation. Harmful effects of contaminants on the ecosystems and humans are characterized by their environmental toxicity. Mercury compounds are considered to be one of the most important pollutants of environment. One of the mercury polluted area is sludge bed Rudriany in Eastern Slovakia, which is contaminated from the former mining activities. The article deals with phytoxicity of mercury in sediments of the sludge bed and creek Rudriany by using Phytotoxkit tests (MicroBioTests Inc., Belgium). The current measured concentrations of mercury were compared with the results obtained in years 1993 and 2005. The sediment phytotoxicity was evaluated based on the germination of seeds and decrease in the root growth of the plant Sinapis alba. Subsequently phytotoxicity tests with model solutions of metal Hg2+ (HgCl2) were carried out and used in solution concentrations: 0.1, 0.2, 0.3, 0.5, 1, 3, 5, 10, 20, 30, 40 mg /1, which were embedded in test tubs with the reference soil. Model experiments were carried out for the purpose to determine the effective concentration (72/EC50) of the reference element, i.e. in which the element causes toxically on ground biotope and consequently, evaluate the sediment ecotoxicity. In the sediment samples potential phytotoxic effects using the parameters percentage inhibition of seed germination (ISG) and percentage inhibition of root growth (IRG) were evaluated.