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BALWOIS Conference – 25, 29 May 2004 – Ohrid, FY Republic of Macedonia Conference on Water Observation and Information System for Decision Support. The impact of mining activities and heavy metal pollution in the Apuseni Mountains, Romania. Mihaela Serban, Graham Bird, Paul Brewer,
BALWOIS Conference – 25, 29 May 2004 – Ohrid, FY Republic of Macedonia Conference on Water Observation and Information System for Decision Support The impact of mining activities and heavy metal pollution in the Apuseni Mountains, Romania Mihaela Serban, Graham Bird, Paul Brewer, Mark Macklin, Dan Balteanu Romanian Academy Institute of Geography University of Wales, UK Institute of Geography and Earth Sciences
MAIN METAL MINING EXPLOITATION IN THE APUSENI MOUNTAINS • River systems categories: • with historical mining activity, presently inactive; • with historical and present mining activity; • with opportunities for the opening of new exploitations • with tailings dam accidents U K R A I N E
Surface water Filtered through 0.45 mm membranes Acidified with 50% HNO3 Cd, Cu, Pb and Zn determined using ICP-MS River channel sediment Sediments collected from bar surfaces Air-dried for > 72 hours Sieved through a < 63 mm mesh Digested in 70 % HNO3 Cd, Cu, Pb and Zn determined using ICP-MS Data collection and laboratory methods
Environmental quality guidelines • Provide a means of evaluating the magnitude of metal contamination relative to potential human health effects. • Water quality guidelines • based upon EU directive 75/440/EEC • Sediment quality guidelines • established by the Dutch Ministry of Housing, Spatial Planning and Environment • Target value: aim to keep concentrations near to or below these value • e.g. 20 mg l-1 for Cu in surface water intended for consumption • Imperative / intervention values: risk to human health and remediation required if concentrations exceed this value • e.g. 50 mg l-1 for Cu in surface water intended for consumption
Aries and Certej catchments Mialu tailings dam, Certej catcment Upper Aries river valley
Certej river basin: a mining affected basin • 78 km2 catchment containing the 40.05 km2 Certej-Coranda mining concession. • Mining history dating back to the Roman period. • Current open-cast exploitation at Coranda with ore processed in Certeju de Sus. • Two tailings ponds in the catchment: Miresului (inactive) and Mialu (active). • Historical tailings dam failure in 1971. • 70 samples taken from 30 sample sites. inactive tailings dam 1971 accident site active tailings dam
River Certej: Cd in surface waters River Certej: Cd in river channel sediment
Floodplain soils & the Miresului pond Distance from channel
River Certej: results summary • Water and channel sediment quality degraded by mining activity, especially at Coranda. • 100 % and 93 % of water samples exceed EU target and imperative limits respectively. Cd concentrations exceed the imperative value by up to 298 times. • In channel sediments, As exceeds Dutch intervention levels at 100 % of sample sites. • Unlike sediment-metal concentrations, solute levels decrease with distance downstream. • Statistically strong relationships (< r2 = 0.72) between solute and channel sediment concentrations. • Possibly suggests the importance of sorption / desorption reactions
Rosia river, a mining affected tributary Rosia Poieni quarry
Results summary • Surface waters and channel sediments of Aries tributaries are severely affected by metal mining activity. • Production of acid mine drainage (pH >3.8) • River Abrud suggests solute pollution is spatially limited. • 99% reduction in solute Cu levels within 2 km of Bucium mine • Solute As, Cd, Pb and Zn levels in the Aries comply with EU directive 75/440/EEC, despite polluted tributaries. • Limestone rich geology facilitates high pH (7.3 – 8.8), physical dilution • Cu contamination in Aries downstream of the Valea Sartas. • 93 % reduction after 13 km, but still exceeds EU target value • Cu levels exceed intervention values prior to Mures confluence, ~90 km downstream of the last contaminated tributary • Cu mined at Rosia Poienii • 2003 water sediments higher than 2002 in the upper basin • 2003 channel sediments higher than 2002 for all sites
River Mures: Cu in surface water River Mures: Pb in river channel sediments
Results summary • Despite heavily polluted tributaries and urban areas, surface waters of the River Mures are not contaminated with Cd, Cu, Pb or Zn. • Physical dilution and high aqueous pH (8.27 – 9.38) • As concentrations exceed target values at 2 sites. • Geology, urban pollution sources, higher pH of hydrolysis for As (XX) • River channel sediments at 92% of sites exceed target values for either Cd, Cu, Pb or Zn. • Increases in concentration downstream of mined tributaries • As concentrations in channel sediment fall below target values at all sites despite higher concentrations in tributaries. • Metal and As levels in waters and channel sediments in the River Mures do not exceed imperative / intervention values.