Woody plant willow in function of river water protection

Abstract

Coastal area surrounding the river Ibar, in the area between cities of Kosovska Mitrovica and Leposavic in the north of Kosovo and Metohija, is occupied with seven industrial waste dumps. These dumps were all part of the exploitation and flotation refinement of raw mineral materials, metallurgic refinement of concentrates, chemical industry, industrial refinement and energetic facilities of Trepca industrial complex. The existing waste dumps, both active and inactive, are of heterogenic chemical composition. Its impact on the river water is shown by the content of heavy metals found in it. Removal of lead, cadmium and zinc would be economically unrewarding, regardless of the technology used. Wooden plant that prevails in this area is white willow. This work is focused on the removal of heavy metals (Pb, Cd and Zn) from the water of the river Ibar using white willow. Roots of the willow are cultivated using the method of water cultures in an individual solution of heavy metals and river water sample. The preparation of the samples for analysis was performed by burning the herbal material and dissolving ashes in the appropriate acids. The concentrations of metals were determined by the stripping analysis. In the investigated heavy metal solutions the biomass increase is 25.6% in lead solution, 27.3% in cadmium and 30.7% in zinc solution. The increase of biomass in nutritional solution, without the heavy metals, is 32.4% and in river water sample 27.5%. The coefficient of bioaccumulation in solutions with heavy metals is 1.6% in lead solution, 1.9% in cadmium and 2.2% in zinc solution. Heavy metals accumulation is 18.74 ?g of lead, 20.09 ?g of cadmium and 22.89 ?g of zinc. The coefficient of bioaccumulation of the water samples, that contained 44.83 ?g/dm3 of lead, 29.21 ?g/dm3 of cadmium and 434.00 ?g/dm3 of zinc, during the period of 45 days, was 30.3% for lead, 53.4% for cadmium and 3.9% for zinc. The concentrations of accumulated metals from the river water are 19.01 ?g of lead, 21.85 ?g of cadmium and 23.96 ?g of zinc in grams dry matter. The obtained results indicate that the willow can contribute to the decontamination of moderately contaminated river water from Pb, Cd and Zn.