River system recovery following the Novaţ-Roşu tailings dam failure, Maramureş County, Romania     

Graham Bird  Paul A. Brewer  Mark G. Macklin  Dan Balteanu  Mihaela Serban  Basarab Driga  Sorin Zaharia 《Applied Geochemistry》2008,23(12):3498-3518

The River Vişeu catchment in Maramureş County, northwestern Romania, has a long history of base and precious metal mining. Between 1994 and 2003 waste from mining activity at Baia Borşa was stored in the Novaţ-Roşu tailings pond in the upper Vişeu catchment. However, in March 2000, the tailings dam failed releasing approximately 100,000 m³ of contaminated water and 20,000 t of mineral-rich solid waste, which was routed downstream through the Rivers Novaţ, Vaser and Vişeu into the River Tisa. Following the accident metal (Cd, Cu, Pb, Zn) concentrations in river water and river channel sediment were assessed in samples collected annually (July 2000, 2001, 2002 and 2003) from 29 sites in the Vişeu catchment, downstream of the tailings pond. Additionally, the speciation of sediment-associated metals was established using a 4-stage sequential extraction procedure (SEP) and Pb isotope analysis (^206/204Pb and ^207/204Pb) was carried out to establish the provenance of contaminated sediments. Metal concentrations in river water were found to comply with EU directive ‘target’ values within four months of the failure. However, the impact of the spill upon river channel sediments was found to be much longer-lasting, with evidence of the delayed downstream remobilization of tailings stored within the narrow Novaţ valley following the dam failure, as well as continued inputs of contaminated sediment to the River Vişeu from the River Tisla, another mining-affected tributary. Comparison with data from other recent tailings dam failures, indicates that river system recovery rates depend upon local geomorphological conditions, hydrological regimes, and the nature and scale of post-spill clean-up operations.  相似文献   

Heavy metal contamination in the Arieş river catchment, western Romania: Implications for development of the Roşia Montană gold deposit     

Graham Bird  Paul A. Brewer  Mark G. Macklin  Mihaela Serban  Dan Balteanu  Basarab Driga 《Journal of Geochemical Exploration》2005,86(1):26-48

The Abrud–Arieş river system, western Romania, is subject to ongoing mining activity associated with Cu, Pb and Zn ore extraction. The catchment contains what is believed to be Europe's largest unutilized Au deposit at Roşia Montană that is planned to be exploited by open-cast mining techniques. The magnitude and environmental significance of metal (Cd, Cu, Pb, and Zn) concentrations in surface water and river channel sediment have been investigated along a 140 km reach of the Rivers Abrud and Arieş and 9 tributaries affected by mining. The speciation of sediment-bound metals was established using a 4-stage sequential extraction procedure (SEP) that identified four chemical phases: (1) exchangeable, (2) Fe/Mn oxides, (3) organic matter/sulphides and (4) residual. Peak solute and sediment-bound metal concentrations were found to occur in the River Abrud downstream of the EM Bucium mine and in mining-affected tributaries, with up to 71% of sites containing sediment metal concentrations in excess of Dutch intervention values. The River Arieş was found to be much less polluted than the River Abrud, with only Cu showing concentrations above guideline values, as a consequence of porphyry Cu mineralization in the catchment. The magnitude and spatial extent of metal pollution is influenced by local physico-chemical conditions and hydrological linkages between mining and local river systems. Sediment-bound Cd and Zn were found to be predominantly associated with the exchangeable phase of the sediment (9–74% and 6–65%, respectively), whilst Fe/Mn oxides (5–76%) and organic matter/sulphides (1–45%) generally accounted for a majority of Pb and Cu partitioning, respectively. Sites of environmentally significant sediment-metal pollution were identified in the Rivers Abrud and Arieş where exchangeable metal concentrations exceeded Dutch intervention values. The implications of metal contamination in the Arieş river basin to the proposed mining development at Roşia Montana are discussed in relation to other contaminated Romanian catchments and with the EU Water Framework Directive.  相似文献