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GENERATION OF SOIL SOLUTION ACID NEUTRALIZING CAPACITY BY ADDITION OF DISSOLVED INORGANIC CARBON
Citation:
David, M. AND G. Vance. GENERATION OF SOIL SOLUTION ACID NEUTRALIZING CAPACITY BY ADDITION OF DISSOLVED INORGANIC CARBON. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/304.
Description:
A Spodosol B horizon(base saturation of 5.4%) collected at the Watershed Manipulation Project site at Lead Mountain, ME, was used to examine soil solution chemistry in response to increasing solution levels of dissolved inorganic carbon (DIC). cid-neutralizing capacity (ANC), determined by Gran titration, increased from -5 to 163 unequiv L-1 in response to increasing DIC, with a corresponding increase in base cations (Ca2+, Mg2+, K+, and Na+). or the negative ANC solutions, degassing increased solution pH (in equilibrium with atmospheric C02) slightly from 4.94 to 5.14, whereas solutions with positive ANC showed large pH shifts (e.g., ANC of 69, pH shift from 4.73 to 6.81). nder equilibrium assumptions and log K-A1 determined from 2.66pH-pAl, measured values from ANC, sum of cations, pH, and degassed pH were found to be in agreement with predictions from a chemical equilibrium model. esults illustrate the importance of pC02 levels and cation exchange from the solid phase in generating solution ANC and determining surface water pH. nvironmental implications and limitations in the use of chemical equilibrium models are discussed.