Facilitated transport of inorganic contaminants in ground water: Part 2. Colloidal transport. Environmental research brief

Technical Report · Mon Jul 01 04:00:00 EDT 1991

OSTI ID:5895950

Puls, R W; Powell, R M; Clark, D A; Paul, C J

The project entailed both field and laboratory components. Field studies evaluated routine sampling procedures for determination of aqueous inorganic geochemistry and assessment of contaminant transport by colloidal mobility. Research at three different metal-contaminated sites has shown that 0.45 micrometer filtration has not removed potentially mobile colloids, when samples have been collected using low pumping flow rates (approximately 0.2-0.3 L/min). However, when pumping velocities greatly exceed formation groundwater flow velocities, large differences between filtered and unfiltered samples are observed, and neither are representative of values obtained with the low flow-rate pumped samples. In controlled laboratory experiments, the stability and transport of radio-labeled Fe2O3 model colloids were studied using batch and column techniques. Variables in the study included flow rate, pH, ionic strength, electrolyte composition (anion/cation), colloid concentration, and colloid size. Iron oxide colloids in the 100-900 nm particle diameter range were not only mobile to a significant extent, but under some hydrogeochemical conditions were transported faster than a conservative tracer, tritium. Particle size and anionic composition together with particle stability provided the highest statistical correlation governing extent of colloidal transport. The rate of colloid-arsenate transport was over 21 times that of the dissolved arsenate.

• Research Organization: Environmental Protection Agency, Ada, OK (United States). Robert S. Kerr Environmental Research Lab.
• OSTI ID: 5895950
• Report Number(s): PB-92-114503/XAB
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
ARSENIC
COLLOIDS
CONTAMINATION
DESORPTION
DISPERSIONS
ELEMENTS
ENVIRONMENTAL TRANSPORT
FIELD TESTS
FLOW RATE
GROUND WATER
HYDROGEN COMPOUNDS
IRON
ISOTOPE APPLICATIONS
MASS TRANSFER
METALS
OXYGEN COMPOUNDS
PARTICLE SIZE
POLLUTION
SAMPLING
SEMIMETALS
SIZE
SORPTION
TESTING
TRACER TECHNIQUES
TRANSITION ELEMENTS
TRITIUM COMPOUNDS
WATER
WATER POLLUTION