Copper activity in soil solution. I. Measurement by ion-selective electrode and Donnan dialysis

Journal Article · · Soil Sci. Soc. Am. J.; (United States)

OSTI ID:6033702

Minnich, M M; McBride, M B

Copper activity in saturation extracts (2:1 soil/solution) of sludge- and Cu-salt-treated soil was estimated by ion-selective electrode (ISE) and by Donnan dialysis. Treatments were a factorial combination of four levels of Cu additions and four levels of total sludge additions. In the Donnan system, the ionic strength of a soil saturation extract was matched with KOAc buffer on opposite sides of a cation perm-selective membrane. At membrane equilibrium, Cu concentration was determined in the KOAc buffer by voltammetry. Extracts of sludge treatments had sufficient Cu buffering capacity to maintain the same Cu/sup 2 +/ activity before and after dialysis; Cu-salt treatments exhibited a lower soil solution Cu/sup 2 +/ activity after dialysis indicating the procedure was inadequate for these treatments. The ISE results were more precise, but the technique is only suited for use in aerobic, Cu-contaminated soils. Values for Cu/sup 2 +/ activity obtained by ISE were approximately an order of magnitude greater than Cu/sup 2 +/ activity values estimated by the Donnan dialysis method. By either procedure, increased total Cu resulted in higher Cu/sup 2 +/ activities and conversely, increased total sludge resulted in decreased Cu/sup 2 +/ activities. Total soluble Cu was highest in the Cu-salt treatments; sludge rate was associated with increased soluble Cu and a decreased proportion of free Cu/sup 2 +/.

• Research Organization: Univ. of Arizona, Tucson
• OSTI ID: 6033702
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 51:3; ISSN SSSJD
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
BUFFERS
CATIONS
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHEMISTRY
COPPER
DIALYSIS
ELEMENTS
ION SELECTIVE ELECTRODE ANALYSIS
IONS
METALS
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
SEPARATION PROCESSES
SLUDGES
SOIL CHEMISTRY
SOILS
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENTS
VOLTAMETRY