Long-term sorption of halogenated organic chemicals by aquifer material. 1. Equilibrium
- Duke Univ., Durham, NC (United States)
- Stanford Univ., CA (United States)
The sorption of tetrachloroethene (PCE) and 1,2,4,5-tetrachlorobenzene (TeCB) was studied on sandy aquifer material from Borden, ON, by using a batch methodology designed to accurately measure sorption over long equilibration periods. Autoclaving was effective in inhibiting biotransformation, and use of fire-sealed glass ampules precluded volatilization losses. Data analysis techniques were developed to accurately account for partitioning to sample headspace and other losses. Sorption isotherms for PCE and TeCB with Borden solids deviated from linearity when a 4-5 order of magnitude range in aqueous concentration was considered. However, in the dilute range (<50 {mu}/l), the deviations from linearity were inconsequential. The sorption of TeCB was approximately 40 times stronger than for PCE, in qualitative accordance with TeCB's approximately 100-fold greater octanol-water partitioning coefficient. For a given solute, the distribution coefficients differed by a factor of 30 among the various size fractions, being greatest for the largest grains. For most Borden solids, the long-term sorption of PCE and TeCB exceeded by more than 1 order of magnitude the predictions of generalized correlations based on hydrophobic partitioning into organic matter. This difference is believed to be partially the result of mineral contributions to sorption, but may also reflect unattainment of equilibrium in previously regressed results - in this study, contact times on the order of tens to hundreds of days were required. For Borden solids, pulverization of solid samples was shown to be a viable expedient to obviate the need for excessively long equilibrations.
- OSTI ID:
- 5316340
- Journal Information:
- Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 25:7; ISSN ESTHA; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
540320 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
ADSORPTION ISOTHERMS
AQUEOUS SOLUTIONS
AQUIFERS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CANADA
CARBON 14
CARBON ISOTOPES
CHLORINATED ALIPHATIC HYDROCARBONS
CHROMATOGRAPHY
CONTAMINATION
DATA
DATA ANALYSIS
DEVELOPED COUNTRIES
DISPERSIONS
ENVIRONMENTAL TRANSPORT
EQUILIBRIUM
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
GAS CHROMATOGRAPHY
GROUND WATER
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
ISOTHERMS
ISOTOPES
LIGHT NUCLEI
MASS BALANCE
MASS TRANSFER
MIXTURES
NORTH AMERICA
NUCLEI
NUMERICAL DATA
ONTARIO
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PARTICLE SIZE
PARTITION
QUANTITY RATIO
RADIOISOTOPES
RESERVOIR ROCK
SAND
SEPARATION PROCESSES
SIZE
SOLUTIONS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
WATER
YEARS LIVING RADIOISOTOPES