Generation of Soil Solution Acid-Neutralizing Capacity by Addition of Dissolved Inorganic Carbon

Mark B David, George F. Vance

Research output: Contribution to journalArticlepeer-review

Abstract

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). Acid-neutralizing capacity (ANC), determined by Gran titration, increased from -5 to 163 μequiv L-1 in response to increasing DIC, with a corresponding increase in base cations (Ca2+, Mg2+, K+, and Na+). For the negative ANC solutions, degassing increased solution pH (in equilibrium with atmospheric CO2) 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). Under equilibrium assumptions and log KA1 determined from 2.66pH - pA1, measured values for ANC, sum of cations, pH, and degassed pH were found to be in agreement with predictions from a chemical equilibrium model. Results illustrate the importance of pCO2 levels and cation exchange from the solid phase in generating solution ANC and determining surface water pH. Environmental implications and limitations in the use of chemical equilibrium models are discussed.

Original languageEnglish (US)
Pages (from-to)1021-1024
Number of pages4
JournalEnvironmental Science and Technology
Volume23
Issue number8
DOIs
StatePublished - Aug 1989

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

Fingerprint Dive into the research topics of 'Generation of Soil Solution Acid-Neutralizing Capacity by Addition of Dissolved Inorganic Carbon'. Together they form a unique fingerprint.

Cite this