Ecological potential of Epilobium dodonaei Vill. for restoration ofmetalliferous mine wastes

Abstract

Metalliferous mine wastes represent one of the major sources of environmental contamination frommining activities. Bor region (Serbia) is one of the largest copper mine basins in Europe where long-termmining caused severe environmental deterioration and created one of the most degraded locations inSerbia and Europe. At the spontaneously colonized metalliferous mine wastes in Bor, plant species Epilo-bium dodonaei dominates in the mine slopes and mine waste surfaces. Epilobium dodonaei has the statusof endangered and protected species in parts of European range (i. e. plant is included in the Red listsof the countries in the Carpathian mountains region), primarily due to losses of natural gravel habitats.The main focus of this research was physico-chemical characterization of mine waste, assessment ofphytoremediation potential and plant metabolic stress response of Epilobium dodonaei at the hot spotmetalliferous mine site in order to evaluate the possibility for application of endangered species in eco-logical restoration. The Bor mine wastes are characterized by coarse soil texture, various pH (4.58–8.30),and elevated concentrations of arsenic (44.5–271 mg kg−1) and copper (311–2820 mg kg−1) that exceedthe Serbian limiting threshold and remediation values. Oxidation of metal-sulfide minerals on waste sur-face leads to increased acidity, followed by elevated metal mobility of the mine spoil solution. Contentof arsenic, copper, lead and zinc in roots of E. dodonaei was correlated with pseudo-total and EDTA-available concentrations in Bor mine spoils. Furthermore, the content of arsenic, copper, lead and zinc inroots (3.98 mg kg−1, 140 mg kg−1, 3.19 mg kg−1, and 72.8 mg kg−1, respectively) and shoots (4.69 mg kg−1,57.7 mg kg−1, 1.17 mg kg−1, and 59.3 mg kg−1, respectively) of E. dodonaei reflected the multi-metal pol-lution at the investigated site. Epilobium dodonaei largely retains copper, lead and zinc in roots thanin shoots and has the potential for phytoremediation of mine wastes. Epilobium dodonaei at Bor minespoil had a high content of malondialdehyde in roots and leaves as well as reduced chlorophylls andcarotenoids content in leaves, indicating great oxidative stress. However, elevated arsenic and coppercontent could promote biosynthesis of antioxidants in roots and leaves of E. dodonaei at mine spoil. Cre-ation of an endangered species habitat on mine waste rocks of the Bor mining area and similar sites ofCarpatho-Balkan metallogenic province could successfully contribute to the preservation of E. dodon-aei. Development of practical procedures for the selection and application of endangered plant species inreclamation should create stronger link between ecological restoration and conservation biology. Finally,the application of endangered plant species should take a more prominent role in the restoration processand ecosystem design