991.
A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage
(AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge
of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of
the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted
to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water
of the same target area.
The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok
Creek such as Fe, SO
4 and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO
4 and Al, significantly depends on the kinds of the precipitates. When FeOHSO
4 and AlOHSO
4 are assumed to precipitate, the maximum removal fractions of SO
4 and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated
when SO
4 is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important
in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability
of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation
fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the
pollutants in the stream water polluted by AMD and other point sources.
Received: 12 November 1997 · Accepted: 30 March 1998
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