Dissolution of dense chlorinated solvents into ground water: 1. Dissolution from a well-defined residual source

Michael Anderson, Richard Johnson, James Pankow

Research output: Contribution to journalArticle

96 Citations (Scopus)

Abstract

When found dissolved in ground water, chlorinated hydrocarbon (CHC) solvents such as tetrachloroethylene (PCE) are nearly always encountered at concentrations far below their solubilities. This is true even in cases when it is known or at least strongly suspected that actual liquid solvent is present in the aquifer. In contrast, laboratory studies using columns packed with porous media containing various organic fluids have indicated that when water is forced to flow through a zone containing an immobile organic fluid, saturation concentrations can be achieved rapidly. This study investigated the concentrations and mass removal rates obtainable when simulated ground water is free to flow at least partially around a zone of porous medium that contains solvent in a state of stable, residual saturation. Reductions in the mass removal rate due to reduced permeability in the solvent zone were found to be minimal under the conditions of the experiment. Thus, near the source the plume was essentially the same width as the source zone, and PCE concentrations in the center of the plume were at or near saturation, even at water velocities of 100 cm/day. The fact that CHC aqueous concentrations in ground-water samples are typically far below saturation is, therefore, likely not due to limited dissolution from the fingers of residual solvent. Probable explanations include the preferential formation of thin pools rather than fingers of CHC, dispersion during transport, and dilution by uncontaminated water in monitoring or pumping wells.

Original languageEnglish (US)
Pages (from-to)250-256
Number of pages7
JournalGround Water
Volume30
Issue number2
StatePublished - Mar 1992

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Groundwater
Dissolution
dissolution
chlorinated hydrocarbon
groundwater
saturation
Porous materials
porous medium
plume
Water
Fluids
fluid
tetrachloroethylene
Aquifers
water
Dilution
pumping
solubility
dilution
Solubility

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Water Science and Technology

Cite this

Dissolution of dense chlorinated solvents into ground water : 1. Dissolution from a well-defined residual source. / Anderson, Michael; Johnson, Richard; Pankow, James.

In: Ground Water, Vol. 30, No. 2, 03.1992, p. 250-256.

Research output: Contribution to journalArticle

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