1. 1 Department of Biology-Chemistry, Faculty of Chemistry, Biology, Geography , West University of Timisoara , Pestalozzi 16, Timisoara, 300115 , Romania
2. 2 Department of Chemistry-Biology, Institute for Advanced Environmental Research , West University of Timisoara , Oituz 4C, Timisoara, 300086 , Romania
3. 3 Mining and Metallurgy Institute Bor , Zeleni bulevar 35, 19210 Bor , Serbia