The impact of acid treatment on soilwater chemistry at the HUMEX site

• Published in: Environment International; (United States) 1994, Vol.20 (3), p.277-286
• Main Authors: Vogt, R.D., Ranneklev, S.B., Mykkelbost, T.C.
• Format: Article
• Language: English
• Subjects: 540320 > Environment, Aquatic-- Chemicals Monitoring & Transport-- (1990-); ACIDIFICATION; Applied sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; CHEMISTRY; DEVELOPED COUNTRIES; ENVIRONMENTAL EFFECTS; ENVIRONMENTAL SCIENCES; EUROPE; Exact sciences and technology; FIELD TESTS; LAKES; NORWAY; OXYGEN COMPOUNDS; Pollution; SCANDINAVIA; Soil and sediments pollution; SOIL CHEMISTRY; SOILS; SULFATES; SULFUR COMPOUNDS; SURFACE WATERS; TESTING; WESTERN EUROPE 540220 > Environment, Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/0160-4120(94)90111-2

The effects of acid treatment on soilwater dissolved organic carbon (DOC) and inorganic chemistry are being monitored at the Humic Lake Acidification Experiment (HUMEX) in western Norway. The HUMEX project involves artificial acidification of half of a dystrophic lake and the corresponding drainage basin. Soil water chemistry data were collected from 30 monitoring lysimeters and 130 grid lysimeters. The samples from the monitoring lysimeters were collected before and, for a period of two years, after the onset of acid treatment. Operationally-defined functional fractions of DOC showed that hydrophilic (HPI) and hydrophobic (HPO) acids account for 60% to 90% of the DOC. In soils rich in DOC, the HPO acids were dominant, whereas in mineral soil horizons low in DOC, the HPI acid fractions were highest. The amount of DOC relative to labile aluminum and iron may determine the HPO/HPI acid ratio. The sulphate concentration has increased more in the treated than in the reference side. Coincident decreases in DOC and organically complexed aluminum (Al o) concentrations were observed for surface histosol locations. The temporal and spatial variations in c(Al o) were mainly explained by variation in c(DOC).