Bioaccumulation and distribution of Pb, Ni, Zn and Fe in stinging nettle (Urtica dioica) tissues and heavy metal-contamination assessment in the industrial zone of smelter Ferronikeli (Drenas-Kosovo).

Abstract

Here, we determined the concentrations of Pb, Ni, Zn and Fe in the soil and in vegetative organs of stinging nettle (Urtica dioica) collected from the banks of the Drenica River in the vicinity of the Ferronikeli smelter. The results were compared with samples collected from the banks 20 km (Shalë village) upriver. In addition, the bioaccumulation factor (BCF) and translocation factor (TF) were determined. Meanwhile, to evaluate the level of pollution in the study area was used the contamination factor (CF), potential ecological risk factor ($E_r^i$) and the potential ecological risk index (RI). The order of heavy metals according to their concentration in the soil samples at both sampling sites was as follows: Fe > Ni > Zn > Pb. Concentrations in excess of the limits allowed for soils in the samples collected in the vicinity of the smelter were recorded for Pb (173.13 mg kg^-1), Zn (1217.48 mg kg^-1), and Ni (1443.93 mg kg^-1), while at the control site, Zn (270.82 mg kg^-1) and Ni (375.47 mg kg^-1) were found in excess concentrations. But lead (Pb) level was under allowed limit. The data showed that the stinging nettle is not a hyperaccumulator because BCF < 1 at both sites for all metals under study. Furthermore, analysis of the translocation factor (TF_steam/root) showed that at low of heavy metal concentrations, their mobility was higher (TF > 1). The lowest mobility (TF < 1) was observed at site I (Poklek), where the concentration of heavy metals was higher, except for Fe. The opposite was shown for mobility of metals from stems to leaves (TF_leave/steam). The evaluation of CF showed that the area near the Ferronikeli smelter had low degree of Pb, moderate degree of Zn and considerable degree of Ni contamination. The values of RI indicate low potential ecological risk index.