CaCO₃ Neutralization of Acidified Surface Waters

Calcium carbonate was utilized to neutralize an acidic lake and stream in the Adirondack Region of New York state. Theoretical calculations based on aqueous base neutralizing capacity underestimated the CaCO₃ dose required to achieve lake neutralization (pH 6.5) for a year. It would appear that lake sediments have a profound influence on base dose requirements. Calcium carbonate neutralization altered water column pH, calcium, acid neutralizing capacity, dissolved inorganic carbon, dissolved organic carbon, free fluoride, aluminum, manganese, zinc, and copper levels. Chemical equilibrium models appear to be a useful tool in predicting changes in aqueous aluminum chemistry. While calcium carbonate appears to be an effective means of accomplishing lake neutralization, there are potentially deleterious consequences associated with its use.