Effects of pH and other solution parameters on the activities of cadmium, copper, and zinc cations in soil solutions

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5523982

Hung, J J

The activities of Cd, Cu, and Zn cations in soil extracts were measured by the method of Donnan membrane equilibrium-electrothermal atomization atomic absorption spectrophotometry to study the factors controlling the concentrations of dissolved metals in soil-water systems. Desorption-ion exchange was the mechanism found to control the activities of the cationic forms of Cd and Zn in Wisconsin soils and sludge-amended soils, except for Zn in limed soils where its free ion activity is controlled by the solubility of franklinite (ZnFe/sub 2/O/sub 4/). The concentrations of dissolved Cd, Cu, and Zn and the cationic fraction of Cd or Zn in 0.01 M Sr(N)/sub 3/)/sub 2/ extracts of sludge and soils generally decreased as the pH was increased. The free cation activity of Cu was below the detection limit whenever the pH was above 5. In 0.01 M Sr(NO/sub 3/)/sub 2/ extracts of oils, Cd and Zn were found principally in the divalent form, whereas more than 95% of the Cu existed as dissolved complexes. The complexation of Cd and Zn increased with increasing soil:extractant ratios and sludge rates. The value of the distribution coefficients for Zn and Cd between the solid and solution phases in the soil-water system increased as the pH increased. The average number of moles of H/sup +/ replaced by a mole of M/sup 2 +/ was approximately 1.5 for most cases.

• OSTI ID: 5523982
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACIDIFICATION
CADMIUM
CATIONS
CHARGED PARTICLES
CHEMISTRY
COPPER
ELEMENTS
IONS
LIMING
METALS
PH VALUE
PHASE STUDIES
RESPONSE MODIFYING FACTORS
SLUDGES
SOIL CHEMISTRY
SOILS
SOLVENT PROPERTIES
TRANSITION ELEMENTS
ZINC