Solution composition effects on cadmium sorption by forest soil profiles

Journal Article · · J. Environ. Qual.; (United States)

OSTI ID:5405413

Homann, P S; Zasoski, R J

Cadmium sorption can reduce Cd transport through sewage sludge-amended forest soil. Three mineral soil horizons from each of six western Washington State soil series were evaluated for their potential to sorb Cd. Horizons varied in pH from 3.6 to 6.4, in clay content from 100 to 470 g kg/sup -1/, in organic C from 3 to 87 g kg/sup -1/, and in cation exchange capacity from 1.8 to 35.8 cmol/sub c/ kg/sup -1/. Batch equilibrium experiments were conducted in three background solutions (calcium nitrate, calcium sulfate, and sodium sulfate) that had ionic strengths of 0.016 and were maintained at pH values close to the natural soil pH. Between 4 and 97% of the initial 10 ..mu..M Cd was sorbed by 1 g soil in 0.1-L background solution. Sorption varied among the horizons in each soil profile, but there was no consistent trend with depth among the six profiles. Sorption did not differ significantly between calcium nitrate and calcium sulfate solutions. However, it was significantly lower in calcium sulfate than sodium sulfate solution, supporting the hypothesis that calcium competition lowers Cd sorption. The amount of Cd sorbed when a solution concentration of 1 ..mu..M free Cd/sup 2 +/ is maintained (Cd/sub sorbed/) decreased 81% when free Ca/sup 2 +/ increased from 0.09 mM Ca/sup 2 +/ in sodium sulfate to 4.0 mM Ca/sup 2 +/ in calcium sulfate solution. The Cd/sub sorbed/ increased with increased natural soil pH. A horizons had higher Cd/sub sorbed/ than B horizons of similar natural soil pH, possible due to their higher organic matter contents.

• Research Organization: Univ. of California, Davis
• OSTI ID: 5405413
• Journal Information: J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 16:4; ISSN JEVQA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CADMIUM
CALCIUM COMPOUNDS
CALCIUM NITRATES
CALCIUM SULFATES
DISPERSIONS
ELEMENTS
ENVIRONMENTAL TRANSPORT
FORESTS
ION EXCHANGE
LEACHATES
MASS TRANSFER
METALS
MIXTURES
NITRATES
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PH VALUE
SEWAGE
SEWAGE SLUDGE
SLUDGES
SODIUM COMPOUNDS
SODIUM SULFATES
SOILS
SOLUTIONS
SORPTION
SORPTIVE PROPERTIES
SULFATES
SULFUR COMPOUNDS
SURFACE PROPERTIES
WASTES