Solute transport through large unsaturated soil columns

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5607977

Porro, I

Scale effects have been observed between solute transport experiments performed in the laboratory and in the field. This study was conducted to quantify differences between laboratory scale (30 cm long) and field scale solute transport using 6 m long soil columns to represent field conditions. Steady-state tritium, bromide, boron and chromium transport parameters determine from effluent breakthrough curves in small columns packed with homogeneous loamy fine sand were compared with those determined from breakthrough curves obtained from various depths in a large column packed with similar soil. The tritium and bromide transport parameters obtained from the large column were also compared to those obtained from the same large column during transient infiltration of solute containing water and to those obtained from a steady state experiment performed in a second large column packed with 29 alternating 20 cm thick layers of loamy fine sand and silty clay loam. The average tritium dispersivity determined in the large column filled with homogeneous soil was greater (4.53 cm) than that for the small columns (0.64 cm) and for the large layered column (1.38 cm). Dispersivities in the large columns appeared to be unrelated to depth. Sorption coefficients used to model boron and chromium transport also differed between small and large columns. Solute transport predictions for the large column made using sorption-related transport parameters determined in the small columns were good for boron but not for chromium. Steady state solutions of the convection-dispersion equation derived for homogeneous soils accurately described solute transport in the layered column. Solute pulses during transient infiltration lagged behind the wetting front. Transport parameters determined under steady state conditions accurately described transport under transient conditions.

• Research Organization: New Mexico State Univ., Las Cruces, NM (United States)
• OSTI ID: 5607977
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
540230 -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
BENCH-SCALE EXPERIMENTS
BORON
BROMIDES
BROMINE COMPOUNDS
CHROMIUM
CONTAMINATION
ELEMENTS
ENVIRONMENTAL TRANSPORT
FIELD TESTS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
MASS TRANSFER
METALS
SEMIMETALS
SOILS
SOLUTES
TESTING
TRANSITION ELEMENTS
TRITIUM COMPOUNDS