Abstract
This study presents the results obtained in the monitoring of heavy metal (Cu, Cd, Ni, Co and Zn) accumulation in two vegetation species: Urtica dioica and Rubus fruticosum, along the Crisul Negru River (N-W Romania) shore in the period August 2008 - July 2009, reported for a chosen heavy metal unpolluted area, Bulz, on the Crisul Repede River (from the same area, N-W Romania). In this period, 280 leaves samples (140 samples of Urtica dioica and 140 samples of Rubus fruticosus) were collected and processed. The analysis method used was atomic absorption spectrometry. The heavy metal analysis values obtained were statistically processed using average and T test student. From the obtained data, it can be concluded that, even when the values of heavy metals concentration during the studied period were fluctuating, there was no significant difference in the content of heavy metal in the samples taken from Crisul Negru area compared to those registered in the control area (Bulz-Crisul Repede). The fluctuation for the heavy metal concentration can be explained on location, season, weather conditions and species. The dynamic of elements over years was always higher in 2009 than in 2008, probably due the increase of leaking from the mines, or surface runoff during heavy rains. The analysis of the heavy metals concentrations suggested a clear pattern of decreasing in concentration as the sampling sites are further away from the mining sites, suggesting a strong point source of pollution in the headwaters from the mines and a diffuse one due the surface runoff during heavy rains, and possibly due the groundwater infiltrations into the river.