Авторы: Knorr K., Blodau C.

2006 г.

Env.Sci.Techn.

      To study the impact of changes in groundwater flow and chemistry on acidity export from sediments in acid mine drainage (AMD) polluted lakes, a column experiment was carried out. Schwertmannite rich sediment was subjected to three different flow rates (0, 5, and 20 L m-2 a-1), two percolate chemistries (1/1 mmol L-1 vs 10/15 mmol L-1 sulfate/ferrous iron, pH 5), and DOC input (2.5 mmol C L-1). Percolation induced acidity export in all percolated treatments (8.8-40.4 molm-2 a-1) by accelerated proton generation from schwertmannite transformation (18.0-35.9 mol m-2 a-1) and ferrous iron release (3.8- 11.6 mol m-2 a-1) from the sediment matrix. Mobilization increased with flow rate and decreased with sulfate and iron concentrations. Unspecifically bound ferrous iron contents increased within the sediment (up to 40.5 mol m-2 a-1) when iron concentrations in the percolate were high. Reduced sulfur species formed following raises in pH, but acidity consumption through this process (0.3-6.6 mol m-2 a-1) and the formation of carbonates (0.11-0.45 mol m-2 a-1) remained small. The study thus suggests that increases in groundwater inflow remobilize acidity from AMD polluted sediments.

Файл: 637.pdf