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Title: Chlorofluorocarbons as tracers of groundwater transport processes in a shallow, silty and aquifer

Abstract

Detailed depth profiles of chlorofluorocarbons CFC-11 (CFCl{sub 3}), CFC-12 (CF{sub 2}Cl{sub 2}) and CFC-113 (C{sub 2}F{sub 3}Cl{sub 3}) have been obtained from a well-characterized field site in central Ontario. Aquifer materials comprise predominantly silty sands, with a mean organic carbon content of 0.03%. Nearly one-dimensional flow exists at this site, and the vertical migration of a well-defined {sup 3}H peak has been tracked through time. Detailed vertical sampling has allowed CFC tracer velocities to be estimated to within 10%. Comparison with {sup 3}H profiles enables estimation of chlorofluorocarbon transport parameters. CFC-12 appears to be the most conservative of the CFCs measured. Sorption at this site is low (K{sub d} < 0.03), and degradation does not appear to be important. CFC-113 is retarded both with respect to CFC-12 and the respect to {sup 3}H (K{sub d} = 0.09-0.14). CFC-11 appears to be degraded both in the highly organic unsaturated zone and below 3.5 m depth in the aquifer, where dissolved oxygen concentrations decrease to below 0.5 mg L{sup -1}. The half-life for CFC-11 degradation below 3.5 m depth is less than 2 years. While apparent CFC-12 ages match hydraulic ages to within 20% (up to 30 years), apparent CFC-11 and CFC-113more » ages significantly overestimate hydraulic ages at our field site. 37 refs., 9 figs., 3 tabs.« less

Authors:
 [1];  [2];  [3]; ;  [4]
  1. Univ. of Waterloo, Ontario (Canada)
  2. Univ. of Waterloo Ontario (Canada)
  3. Univ. of Utah, Salt Lake City, UT (United States)
  4. Geological Survey, Reston, VA (United States)
Publication Date:
OSTI Identifier:
81158
Resource Type:
Journal Article
Journal Name:
Water Environment Research
Additional Journal Information:
Journal Volume: 31; Journal Issue: 3; Other Information: PBD: Mar 1995
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CHLOROFLUOROCARBONS; TRACER TECHNIQUES; GROUND WATER; AGE ESTIMATION; HYDROLOGY; ENVIRONMENTAL TRANSPORT

Citation Formats

Cook, P G, CSIRO Division of Water Resources, Glen Osmond, Schiff, S L, Solomon, D K, Plummer, L N, and Busenberg, E. Chlorofluorocarbons as tracers of groundwater transport processes in a shallow, silty and aquifer. United States: N. p., 1995. Web. doi:10.1029/94WR02528.
Cook, P G, CSIRO Division of Water Resources, Glen Osmond, Schiff, S L, Solomon, D K, Plummer, L N, & Busenberg, E. Chlorofluorocarbons as tracers of groundwater transport processes in a shallow, silty and aquifer. United States. https://doi.org/10.1029/94WR02528
Cook, P G, CSIRO Division of Water Resources, Glen Osmond, Schiff, S L, Solomon, D K, Plummer, L N, and Busenberg, E. 1995. "Chlorofluorocarbons as tracers of groundwater transport processes in a shallow, silty and aquifer". United States. https://doi.org/10.1029/94WR02528.
@article{osti_81158,
title = {Chlorofluorocarbons as tracers of groundwater transport processes in a shallow, silty and aquifer},
author = {Cook, P G and CSIRO Division of Water Resources, Glen Osmond and Schiff, S L and Solomon, D K and Plummer, L N and Busenberg, E},
abstractNote = {Detailed depth profiles of chlorofluorocarbons CFC-11 (CFCl{sub 3}), CFC-12 (CF{sub 2}Cl{sub 2}) and CFC-113 (C{sub 2}F{sub 3}Cl{sub 3}) have been obtained from a well-characterized field site in central Ontario. Aquifer materials comprise predominantly silty sands, with a mean organic carbon content of 0.03%. Nearly one-dimensional flow exists at this site, and the vertical migration of a well-defined {sup 3}H peak has been tracked through time. Detailed vertical sampling has allowed CFC tracer velocities to be estimated to within 10%. Comparison with {sup 3}H profiles enables estimation of chlorofluorocarbon transport parameters. CFC-12 appears to be the most conservative of the CFCs measured. Sorption at this site is low (K{sub d} < 0.03), and degradation does not appear to be important. CFC-113 is retarded both with respect to CFC-12 and the respect to {sup 3}H (K{sub d} = 0.09-0.14). CFC-11 appears to be degraded both in the highly organic unsaturated zone and below 3.5 m depth in the aquifer, where dissolved oxygen concentrations decrease to below 0.5 mg L{sup -1}. The half-life for CFC-11 degradation below 3.5 m depth is less than 2 years. While apparent CFC-12 ages match hydraulic ages to within 20% (up to 30 years), apparent CFC-11 and CFC-113 ages significantly overestimate hydraulic ages at our field site. 37 refs., 9 figs., 3 tabs.},
doi = {10.1029/94WR02528},
url = {https://www.osti.gov/biblio/81158}, journal = {Water Environment Research},
number = 3,
volume = 31,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 1995},
month = {Wed Mar 01 00:00:00 EST 1995}
}