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Main Title Acid-Base Characteristics of Organic Carbon in the Humex Lake Skjervatjern.
Author Kortelainen, P. ; David, M. B. ; Roila, T. ; Maekinen, I. ;
CORP Author National Board of Waters and the Environment, Helsinki (Finland).;Corvallis Environmental Research Lab., OR.
Publisher c1992
Year Published 1992
Report Number EPA/600/J-93/411;
Stock Number PB93-236487
Additional Subjects Lake Skjervatjern ; Acidification ; Humus ; Organic acids ; Water pollution ; pH ; Distillation ; Anions ; Pollution sources ; Water chemistry ; Norway ; Surface waters ; Aquatic ecosystems ; Reprints ; Foreign technology ; Humic Lake Acidification Experiment ; Dissolved organic carbon
Library Call Number Additional Info Location Last
NTIS  PB93-236487 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 11p
Over the past two decades, acidification has been one of the central issues in environmental research. The subproject of the Humic Lake Acidification Experiment (HUMEX), begun in 1988, was designed to determine the contribution of organic acids to the acidity of Lake Skjervatjern (the HUMEX Lake) and the impacts of the acidification on the characteristics of organic carbon. In order to get an empirical measure for organic acidity, dissolved organic carbon (DOC) was fractionated, isolated, and base-titrated from each half of Lake Skjervatjern. Hydrophobic acids were the dominant organic carbon fraction; the total organic acid content was generally greater than 80% of the DOC. The reliability of the fractionation procedures was tested with synthetic acids and the Nordic Fulvic acid. The DOC fractions did not show high variation over the 1.5-yr acidification period. Hydrophilic acids had consistently greater exchange acidities compared to hydrophobic acids. The dissociation of organic acids during acid-base titrations clearly increased with increasing pH. The high organic anion contribution to the ion balances indicates that humic matter is an important acidity source in Lake Skjervatjern.