Stable Chlorine and Bromine Isotopes in Nature and “Fingerprinting” Contaminants

Chloride and bromide are key components of natural groundwater and rock systems, as well as being common environmental contaminants in road salt/deicers and organochlorine solvents. For over twenty-five years I have worked to develop a better understanding of halide (Cl, Br, F) systematics in the hydrosphere. As a result of this research, and because of increased research demand, UW-EIL set up a δ³⁷Cl preparation facility in the early 1990’s. We are now one of only ten laboratories in the world, and two in Canada, with the capability to analyze stable chlorine isotopes and the only facility to analyze this isotope on a regular basis. We are the second laboratory in the world to analyze stable bromine isotopes. The UW-EIL’s capability to analyze both of these isotopes in a wide variety of compounds and applications is truly unique and has become a rapidly expanding research tool for internal as well as external users.

Ongoing research in Canada and Finland is concerned with water-rock interaction studies related to the safe disposal of radioactive waste. Stable Cl and Br isotopes are used to differentiate geochemical signatures between different continental Shields, rock types and geographical areas. The importance of the UW-EIL’s ability to analyze δ³⁷Cl has been recognized by many of the research groups in Sweden, Finland, Switzerland and Canada that deal with the safe disposal of nuclear waste in crystalline rocks. Ongoing support from Scandinavian and Swiss waste disposal agencies has recently been successfully combined with Canadian support from Ontario Power Generation in an international collaboration. A key component to the study’s success is the UW-EIL’s capability to analyze Cl and Br stable isotopes and tritium.

Understanding of halide isotope geochemistry is continuing to grow with combination of Cl, C, H isotope fingerprinting. It is the first major attempt to fingerprint various subsets of organic compounds and mixtures involved in groundwater contamination. To date 3 ongoing PhD. (Shouakar-Stash, Stotler, Drimmie) theses and 6 completed PhD. theses (three are Professors: Blyth, ARC/Calgary; Harvey, Nebraska; Weaver, Melbourne) and 4 ongoing MSc. theses and 9 completed MSc. theses have been trained to use stable chlorine isotopes in the environment as one of their major research focuses. Past PhD students (Sherwood-Lollar, U of T; Hussain, industry; Cecil, USGS) have also benefited from the ability of UW-EIL to solve difficult isotopic problems.

Selected Publications

• Lehmann, B.E., Love, A. Purtschert, R., Collon, P., Loosli, H.H., Kutschera, W., Beryerle, U., Aeschbach-Hertig, W., Kipfer, R., Frape, S.K., Herczeg, A., Moran, J., Tolstikhin, I.N., Groning, M., 2003. A comparison of ⁸¹Kr-, ³⁶Cl- and ⁴He-groundwater dating in 4 wells in the Great Artesian Basin, Australia. Geochimica et Cosmochimica Acta. or Earth Sci. Planet. Letters, 211, 237-250.
• Shouakar-Stash, O., Frape, S.K. and Drimmie, R.J., 2005. Determination of bromine stable isotopes using continuous-flow isotope ratio mass spectrometry. Analytical Chemistry, 77(13): 4027-4033.
• Shouakar-Stash, O., Rostron, B. J. and Frape, S.K. 2003. Geochemistry and Stable Isotopic Signatures, Including Chlorine Isotopes of the Williston Basin, Canada. The Geological Society of America Annual Meeting, Seattle, USA, 235-10, 574.
• Shouakar-Stash, O., Frape, S.K. and Drimmie, R.J., 2003. Stable carbon, chlorine and hydrogen isotope measurement of selected chlorinated organic solvents. Jour. Contamin. Hydrology, 60:211-228.
• Alexeev, S. V., Alexeeva, L. P., Shouakar-Stash, O. and Frape, S. K. 2004. Geochemical and isotope features of brines of the Siberian platform. The 11th Water Rock Interaction Meeting. Saratoga Springs, NY, USA.
• Hesse, R., Frape, S.K., Egeberg, P.K. and Matsumoto, R., 2000. Stable isotopes studies (Cl, O, H) of interstitial waters from site 997, ODP Leg 164, Blake Ridge gas-hydrate field, west Atlantic Proc. Ocean Drilling Program, 164:129-137.
• Lyons, W.B., Frape, S.K. and Welch, K.A., 1999. History of McMurdo Dry Valley Lakes, Antarctica, from stable chlorine isotope data. Geology, 27:527-530.
• Beneteau, K.M., Aravena, R., and Frape, S.K., 1999. Isotopic characterization of chlorinated solvents – laboratory and field results. Organic Geochemistry, 30:739-753.
• Cecil, L.D., Frape, S.K., Drimmie, R.J., Flatt, H. and Tucker, B.J., 1998. Evaluation of archived water samples using chlorine isotopic data, Idaho National Engineering and Environmental Laboratory, Idaho, 1966-93. U.S. Geol. Surv. Water Res. Investigation Report 98-4008, 27p.