Barrie Webster - Conference Presentations

Invited papers:

G.R.B. Webster, L.P. Sarna, and D.C. Hay. 1997. SPME in the Determination of Kow Values of Chlorinated Paraffins and Other Environmental Contaminants, 80th Canadian Society for Chemistry Conference, Windsor, ON, June 1-4.

G.R.B. Webster, K.N. Graham, L.P. Sarna, H. Ng, D.A. Cancilla, J.D. Gaynor, C.S. Tan, C.F. Drury, and T. Welacky. 1995. Comparison of SPME-GC-EC with Solvent Extraction-GC-MS and Immunoassay for Metolachlor Residues in Agricultural Runoff Water, 78th Canadian Society for Chemistry Conference, Guelph, ON, May 28 - June 1.

G.R.B. Webster, H. Jin, N.J. Holliday, P. Pines, and A. Richard Westwood. 1995. An Elm Bark Beetle Bioassay for Residual Efficacy of Chlorpyrifos and Cypermethrin used for the Control of Dutch Elm Disease in Manitoba, 27th Eastern Canadian Pesticide Residue and Environmental Contaminants Workshop, Sault Ste. Marie, ON, May 25-27. 1995

G.R.B. Webster, L.P. Sarna, K.N. Graham, K.A. Anderson, and A-M. Tugulea. 1994. Solventless Residue Analysis of Pesicides and Other Contaminants in Water and Soil. Inorganic Photochemistry and Environmental Speciation: Symposium at the University of Calgary, October 29, 1994.

G.R.B. Webster. 1993. Environment and Society: Using the Manitoba Clean Environment Process. Western Inter-University Geological Conference 1993, Winnipeg, MB, January 14-16.

D.S. Gamble, C.H. Langford, and G.R.B. Webster. 1992. Interactions of Pesticides and Metal Ions with Soils: Unifying Concepts, International Conference on Organic Substances in Soil and Water - Natural Constituents and their Influence on Contaminant Behaviour, Conference Handbook and Abstracts, Lancaster, U.K., September 14-17.

G.R.B. Webster. 1991. Pesticides: Where do they come from and where do they go when they die? Opening Lecture, C.I.C. Student Conference, Winnipeg, MB, May 2-4.

M.D. Segstro, G.R.B. Webster, M.R. Servos, and D.C.G. Muir. 1991. Molluscs as Indicators of Dioxin Availability in Contaminated Lake Sediments. 2nd Soil Residue Analysis Workshop (IAEAC), Lausanne, Switzerland, March 11-13.

G.R.B. Webster and G.G. Choudhry. 1990. The Role of Humic Acids in the Photodegradation of Pesticides. Quatriemes Entretiens du Centre Jacques Cartier, Rhone-Alpes, France. December 4-7.

G.R.B. Webster and G.A. Ross. 1990. Field Testing of Herbicide Residue Bioavailability: Coordination with Laboratory Test Methods. Soil and Groundwater Contamination from Agricultural Sources. 73rd Canadian Chemical Conference, Halifax, July 15-20.

G.R.B. Webster. 1990. Soil and Ground Water Contamination - Decisions for the Future. First presentation in Plenary Session, 27th Annual Alberta Soil Science Workshop Proceedings, 1-11. Edmonton, AB, February 20-22.

G.R.B. Webster, M.R. Servos, P. Sarna, G.G. Choudhry, and D.C.G. Muir. 1987. Methods for Dissolving Hydrophobics for Studies of Solution Interaction with Dissolved Organic Matter. Symposium on Influence of Aquatic Humic Substances on Fate and Treatment of Pollutants, Division of Environmental Chemistry, American Chemical Society, ACS National Meeting, Denver, CO, U.S.A., April 5-10.

G.R.B. Webster, D.H. Muldrew, L.P. Sarna, and D.C.G. Muir. 1985. Dissolved Organic Matter Mediated Aquatic Transport of Chlorinated Dioxins. 5th International Symposium on Chlorinated Dioxins and Related Compounds, Bayreuth, Germany, September 16-19.

G.R.B. Webster, L.P. Sarna, K. Friesen, D.H. Muldrew, P.E. Hodge, and D.C.G. Muir. 1984. Environmental Fate Modelling of Chlorinated Dioxins: Determination of Physical Constants by Chromatographic Techniques. 4th International Symposium on Dioxins and Related Compounds. Ottawa, ON, Canada, October 16-18.

G.R.B. Webster. 1982. Toxic Chemicals in Aquatic Systems. 38th Annual Meeting of the Entomological Society of Manitoba, Winnipeg, Canada, November 4-5.

A.E. Smith, G.R.B. Webster, B.L. Worobey, and M. Dudas. 1981. Agricultural Land Degradation: Impact of Agricultural Inputs. Alberta Soil Science Workshop, Edmonton, AB, Canada, February 24 25, 27 pp.

Contributed papers:

K.N. Graham, G.R.B. Webster, and L.P. Sarna. 1997. Analysing Diesel Fuel Contaminants in Soil: A Methods Comparison, 32nd Annual Western Canada Trace Organic Residue Analysts' Workshop, Winnipeg, Manitoba, May 4-7.

D.C. Hay, L.P. Sarna, and G.R.B. Webster. 1997. SPME-Alkylation of Residues of Chlorinated Phenols and Acid Herbicides in Soils and Water, 7th Annual Meeting of SETAC-Europe, Amsterdam, The Netherlands, April 6-10.

A-M. Tugulea, L.P. Sarna, and G.R.B. Webster. 1996. Solid Phase Microextraction (SPME) of the Herbicide Atrazine in Aqueous Soil Suspensions, 4th Soil and Sediment Contaminant Analysis Workshop, Lausanne, Switzerland, September 23-25.

A-M. Tugulea, L.P. Sarna, and G.R.B. Webster. 1996. SPME Determination of Freely Dissolved Atrazine in Soil Slurries with High Humic Substance Content, 8th Meeting of the International Humic Substances Society, Wroclaw, Poland, September 9-14, Poster # C41.

A-M. Tugulea, L.P. Sarna, and G.R.B. Webster. 1996. Direct SPME-based Method for the Extraction of the Herbicide Atrazine from Soil Slurries, EnviroAnalysis '96, May 13-16, Ottawa, ON, Poster # 6.

D.C. Hay, G.R.B. Webster, and L.P. Sarna. 1996. Innovative Technique for the Analysis of Chlorophenols and Acid Herbicides in Soils and Water, EnviroAnalysis '96, May 13-16, Ottawa, ON, Poster # 7.

K.N. Graham, G.R.B. Webster, and L.P. Sarna. 1996. Preliminary Evaluation of Analytical Methodologies for Diesel Fuel Derived Contaminants in Soil, EnviroAnalysis '96, May 13-16, Ottawa, ON, Poster # 8.

Y.F. Ng, J.D. Gaynor, G.R.B. Webster, D.A. Cancilla, C.S. Tan, C.F. Drury, and R.J. Maguire. 1996. Metolachlor Transport in Surface Runoff and in Tile Drainage During a Large Storm Event from Field Plots, 31st Central Canadian Symposium on Water Pollution Research, National Water Research Institute, Burlington, ON, February 6-7.

A-M. Tugulea, L.P. Sarna, and G.R.B. Webster. 1996. Use of a New SPME-based Method in the Study of the Soil Sorption of the Herbicide Atrazine, Proceedings of the 39th Annual Meeting, Manitoba Society of Soil Science, Winnipeg, MB, January 3-4, in press.

K.N. Graham, L.P. Sarna, and G.R.B. Webster. 1996. Preliminary Evaluation of Analytical Methodologies for Diesel Fuel Derived Contaminants in Soil, Proceedings of the 39th Annual Meeting, Manitoba Society of Soil Science, Winnipeg, MB, January 3-4, in press.

D.A. Hay, L.P. Sarna, and G.R.B. Webster. 1996. Title, Proceedings of the 39th Annual Meeting, Manitoba Society of Soil Science, Winnipeg, MB, January 3-4, in press.

G.R.B. Webster, L.P. Sarna, D.A. Thomas, E.A. Braekevelt, G. Tomy, S. Tittlemier, K.G. Drouillard, T. Hiebert, K.J. Friesen, A. Fisk, G.A. Stern. 1995. SPME-GC-EC of Chlorinated Paraffins in Water, 16th Annual Meeting, Society of Environmental Toxicology and Chemistry, Vancouver, B.C., November 5-9.

G.R.B. Webster, K.N. Graham, L.P. Sarna, H. Ng, and J.D. Gaynor. 1995. SPME-GC-EC compared with More Conventional Methods for Metolachlor Residues in Agricultural Runoff and Tile Drainage Water, 27th Eastern Canadian Pesticide Residue and Environmental Contaminants Workshop, Sault Ste. Marie, ON, May 25-27.

G.R.B. Webster, K.N. Graham, L.P Sarna, J.D. Gaynor, and H. Ng. 1995. Solid Phase Microextraction (SPME) of the Herbicide Metolachlor in Runoff Water Samples, 7th Symposium on Handling of Environmental and Biological Samples in Chromatography, Lund, Sweden, May 8-10.

K.N. Graham, G.R.B. Webster, and L.P. Sarna. 1995. Solid Phase Microextraction-Gas Chromatography for Analysis of Diesel Residues in Soil, Proceedings of the 38th Annual Meeting, Manitoba Society of Soil Science, Winnipeg, MB, January 3-4, 42-47.

K.L. Anderson, L.P. Sarna, G.R.B. Webster, and N.J. Holliday. 1995. Analysis of Lindane in Water and Soil by Solid Phase Microextraction, Proceedings of the 38th Annual Meeting, Manitoba Society of Soil Science, Winnipeg, MB, January 3-4, 154-161.

G.R.B. Webster, L.P. Sarna, K.A. Anderson, and K.N. Graham. 1994. Application of Solid Phase Microextraction to the Analysis of Chlorinated Contaminants in Environmental Matrices, 15th Annual Meeting, Society of Environmental Toxicology and Chemistry, Denver, CO, U.S.A., October 30 - November 3, Abstr. 94.

L.P. Sarna, K.N. Graham, and G.R.B. Webster. 1994. Innovative Analytical Method for Organic Contaminant Residues in Soil and Water, Canadian Society for Chemistry - 1994 Conference, Environment Division, Winnipeg, MB, Canada, May 29-June 2, Abstr. 332.

K.N. Graham, L.P. Sarna, and G.R.B. Webster. 1994. Solid Phase Microanalysis/Gas Chromatography Analysis of Hydrocarbon Fuel Residues in Soil and Water, 24th International Symposium on Environmental Analytical Chemistry, Ottawa, ON, Canada, May 16-19, Abstr. 4P21.

G.R.B. Webster, L.P. Sarna, and K.N. Graham. 1994. Innovative Analysis of the Pesticides Metolachlor, Atrazine, and Diclofopmethyl in Water by SPME, 29th Annual Pesticide and Trace Analysis Seminar for Western Canada, Vancouver, B.C., Canada, May 3-5.

D.S. Gamble, C.H. Langford, G.R.B. Webster, J. Li, G.F.R. Gilchrist, S. Cathum, and D.W. Gutzman. 1993. Emerging Mechanisms for Pesticide-Soil Interactions Based on Chemical Stoichiometry, 3rd Soil and Sediment Contaminant Analysis Workshop, August 8-11, Winnipeg, MB.

G.R.B. Webster, L.P. Sarna, P. Wolfe, and D.S. Gamble. 1993. Separating the Biotic from the Abiotic for Several Pesticide-Soil Interaction Combinations, 3rd Soil and Sediment Contaminant Analysis Workshop, August 8-11, Winnipeg, MB.

H. Jin, G.R.B. Webster, and L.P. Sarna. 1993. Supercritical Fluid Extraction versus Liquid Extraction of Chlorpyrifos and its Major Metabolites from Soil, 3rd Soil and Sediment Contaminant Analysis Workshop, August 8-11, Winnipeg, MB.

H. Jin, G.R.B. Webster, and L.P. Sarna. 1993. Supercritical Fluid Extraction Optimization vs. Liquid Extraction of Chlorpyrifos and its Major Metabolites from Soil, 28th Annual Western Canada Workshop of Pesticide and Trace Organic Residue Analysis, April 27-28, Winnipeg, MB.

J.W. Leung, A. Sundaram, and G.R.B. Webster. 1993. Role of a Cationic Surfactant, Ethomeen T/25 and an Organosilicone Surfactant Silwet L-77 on Rainfastness of Vision Formulation for the Control of Trembling Aspen (Populus tremuloides Michx.), 25th Annual Eastern Canada Pesticide residue and Environmental Contaminants Workshop, May.

H. Jin, G.R.B. Webster, and N.J. Holliday. 1993. Persistence of Chlorpyrifos and Cypermethrin and their Metabolites in Soil and Litter following use for Dutch Elm Disease Control. 36th Annual Meeting of the Manitoba Soil Science Society, January 5-6, Winnipeg, MB.

D.F. Kenny, D.C.G. Muir, C.F. Shaykewich, and G.R.B. Webster. 1992. Runoff Losses of Atrazine, Bromoxynil Octanoate and Diclofop-Methyl from Manitoba Soils. 13th Annual Meeting of Society of Environmental Toxicology and Chemistry, Cincinnati, OH, U.S.A., November 8-12.

H. Jin, G.R.B. Webster, N.J. Holliday, and A.R. Westwood. 1992. Chemical and Biological Monitoring of Residues of Insecticides Used in the Control of Elm Bark Beetles in Manitoba. Annual Meeting of the Entomological Society of Manitoba, November 5-6, Winnipeg, MB.

D.S. Gamble, G.R.B. Webster, and C.H. Langford. 1992. Atrazine Chemical Species and Reactions in a Mineral Soil, International Conference on Organic Substances in Soil and Water - Natural Constituents and their Influence on Contaminant Behaviour, Conference Handbook and Abstracts, September 14-17, Lancaster, U.K.

G.R.B. Webster, H. Jin, N.J. Holliday, and A.R. Westwood. 1992. Fate of Chlorpyrifos and Cypermethrin in Elm Bark, Litter, and Soil. Proceedings XIX International Congress of Entomology (Abstracts), 563, June 28-July 4, Beijing, China.

H. Jin, G.R.B. Webster, and L.P. Sarna. 1992. GC Analysis of Chlorpyrifos and Major Metabolites in Elm Bark, Litter, and Soil, 27th Annual Western Canada Workshop of Pesticide and Trace Organic Residue Analysis, April 29-May 1, Saskatoon, SK.

M.D. Segstro, M.R. Servos, G.R.B. Webster, and D.C.G. Muir. 1991. Bioavailability of Sediment Associated Dioxin Congeners to Mussel and Crayfish in Freshwater Enclosures. 18th Annual Aquatic Toxicity Workshop, Ottawa, ON, October 1-3.

D.C.G. Muir, S. Lawrence, M. Holoka, W.L. Fairchild, M. Segstro, G.R.B. Webster, and M.R. Servos. 1991. Partitioning of Polychlorinated Dioxins and Furans between Water, Sediments, and Biota in Lake Mesocosms, 11th International Symposium on Chlorinated Dioxins and Related Compounds, Research Triangle Park, NC, U.S.A., September 23-27.

D.C.G. Muir, K.J. Friesen, G.R.B. Webster, and W.L Lockhart. 1991. Fate and Bioavailability of Organic Contaminants in the Aquatic Environment: The Case of Chlorinated Dioxins and Furans. 74th Canadian Chemical Conference, Hamilton, ON, June 2-6.

G.R.B. Webster, W.D. Buchannon, L.P. Sarna, D.F. Kenny, and J.B. Westmore. 1991. An Apparent Anomaly in the Mass Spectrometry of Bromoxynil Octanoate. 19th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Edmonton, AB, April 29-30.

M.D. Segstro, D.C.G. Muir, M.R. Servos, and G.R.B. Webster. 1990. Bioavailability of Chlorinated Dioxins to Mussel and Crayfish in Lake Mesocosms. 11th Annual Meeting of the Society of Environmental Toxicology and Chemistry, Arlington, VA, U.S.A., November 11-15.

L.J. Shapiro, G.R.B. Webster, B.M. Poersch, I. Seunarine, R. Walker, K. Neilson, S. Gould, and L. Reid. 1990. Effects of Exposure to Carbofuran on Mallard Ducks (Anas platyrhynchos platyrhynchos). Annual Meeting of the Southern Society for Philosophy and Psychology, Louisville, KY, U.S.A., April.

G.A. Ross, C.F. Shaykewich, and G.R.B. Webster. 1990. Bioavailability of Soil Residues of Triallate and Trifluralin in Association with a Herbicide Carryover Study. 10th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Regina, SK, April 24-25.

D.F. Kenny, D.C.G. Muir, C.F.Shaykewich, and G.R.B. Webster. 1990. Residues in Runoff Water from Erosion Plots Treated with Aatrex and Hoegrass II. 10th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Regina, SK, April 24-25.

G.A. Ross, G.R.B. Webster, and C.F. Shaykewich. 1990. Factors Affecting the Carryover and Bioavailability of Triallate and Trifluralin on Manitoba Soils. 33rd Annual Manitoba Society of Soil Science Meeting, Winnipeg, MB, January 9-10.

M.D. Segstro, K.J. Friesen, and G.R.B. Webster. 1989. The Role of Volatilization in the Dissipation of Chlorinated Dioxins from Soil. 10th Annual Meeting of the Society of Environmental Toxicology and Chemistry, Toronto, ON, Canada, October 29 - November 2.

D.T.H.M. Sijm, W. Seinen, A Opperhuizen, A. Yarachewski, D.A. Metner, D.C.G. Muir, and G.R.B. Webster. 1989. 10th Annual Meeting of the Society of Environmental Toxicology and Chemistry, Toronto, ON, Canada, October 29 - November 2.

B.F. Rordorf, L.P. Sarna, G.R.B. Webster, S.H. Safe, L.M. Safe, D. Lenoir, and O. Hutzinger. 1989. Thermal Properties of Environmental Contaminants: Vapor Pressure Measurements on Halogenated Dibenzo-p-dioxins and Dibenzofurans. 9th International Symposium on Chlorinated Dioxins and Related Compounds, Toronto, ON, Canada, September 17-22.

K.J. Friesen, J. Vilk, L.P. Sarna, G.R.B. Webster, and D.C.G. Muir. 1989. Aqueous Solubilities of Polychlorinated Dibenzofurans. Temperature Dependence and Structure Correlation. 9th International Symposium on Chlorinated Dioxins and Related Compounds, Toronto, ON, Canada, September 17-22.

B.F. Rordorf, L.P. Sarna, G.R.B. Webster, S.H. Safe, L.M. Safe, D. Lenoir, and O. Hutzinger. 1989. Thermal Properties of Environmental Contaminants: Vapor Pressure Measurements on Halogenated Dibenzo-p-dioxins and Dibenzofurans. Symposium on Chemical Thermodynamics, Calorimetry, and Thermal Analysis, Basel, Switzerland, September 10-14.

J. Kochany, G.G. Choudhry, and G.R.B. Webster. 1989. Environmental Behaviour of Bromoxynil Herbicide. Proceedings VII International Conference: Chemistry for Protection of the Environment, Lublin, Poland, September 4-7.

G.G. Choudhry, J. Kochany. and G.R.B. Webster. 1989. Effects of Sodium Chloride on the Environmental Aquatic Phototransformation of Bromoxynil including Photoincorporation of Chloride Ions. 18th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, April 25-26, Winnipeg, MB.

B.M. Poersch, G.R.B. Webster, and L.J. Shapiro. 1989. Behavior and Growth of Normal and Carbofuran Treated Mallard Ducklings (Anas platyrhynchos platyrhynchos). Psychology Undergraduate Research Conference, Winnipeg, MB, May.

G.A. Ross, G.R.B. Webster, C.F. Shaykewich, and G.G. Choudhry. 1989. Persistence of the Herbicides Trifluralin and Triallate on Artificially Eroded Soil. 32nd Annual Mtg. Manitoba Soil Sci. Soc., Winnipeg, MB, Canada, Jan. 6-7.

K.J. Friesen, N.J. Graham, M.D. Segstro, G.R.B. Webster, and D.C.G. Muir. 1988. Fate of 1,2,3,4,7-Pentachlorodibenzo-p-dioxin in Pond Mesocosms as a Function of the Mode of Application. 8th International Symposium on Chlorinated Dioxins and Related Compounds, Umea, Sweden, August 21-26.

K.J. Friesen, G.R.B. Webster, and D.C.G. Muir. 1988. Thermodynamics of the Aqueous Solubilities of a Series of Polychlorinated Dibenzo-p-dioxins. 8th International Symposium on Chlorinated Dioxins and Related Compounds, Umea, Sweden, August 21-26.

D.C.G. Muir, M.R. Servos, D.M. Whittle, D.B. Sergeant, and G.R.B. Webster. 1988. Does OCDD Bioaccumulate in Fish? Evidence from Field Monitoring and from Experimental Studies with White Suckers (Catostomus spp.). 8th International Symposium on Chlorinated Dioxins and Related Compounds, Umea, Sweden, August 21-26.

M.D. Segstro, K.J. Friesen, G.R.B. Webster, and A.E. Smith. 1988. Environmental Fate of 1,2,3,4,7-Penta- and Octachlorodibenzo-p-dioxin in a Saskatchewan Soil. Internat. Assoc. Environ. Anal. Chem., 1st Soil Residue Analysis Workshop, Winnipeg, MB, Canada, August 8-10.

J. Kochany, G.G. Choudhry, and G.R.B. Webster. 1988. Environmental Aquatic Photolytic Fate of Bromoxynil in the Absence and Presence of Soil Fulvic Acids. Internat. Assoc. Environ. Anal. Chem., 1st Soil Residue Analysis Workshop, Winnipeg, MB, Canada, Aug. 8-10.

K.J. Friesen, M.D. Segstro, G.R.B. Webster, and A.E. Smith. 1988. Environmental Fate of 1,2,3,4,7-Pentachlorodibenzo-p-dioxin and Octachlorodibenzo-p-dioxin in Prairie Soil. 23rd Annual Workshop for Pesticide and Trace Organic Residue Analysts - Western Canada, Regina, SK, April 27-28.

G.G. Choudhry and G.R.B. Webster. 1988. Effect of Soil Organic Matter on Herbicide and Soil Chemistry. 17th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Regina, SK, April 25-26.

J. Kochany, G.G. Choudhry, and G.R.B. Webster. 1988. Environmental Aquatic Photochemistry of the Herbicide Bromoxynil. 17th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Regina, SK, April 25-26.

G.G. Choudhry, C.M. Cho, T.B. Goh, C.F. Shaykewich, and G.R.B. Webster. 1988. The Role of Soil Organic Matter in Reducing Soil Erosion and Enhancing Soil Fertility. Proc. Manitoba Soil Sci. Soc. Meeting, Winnipeg, MB, January 5-6.

G.G. Choudhry and G.R.B. Webster. 1988. Abiotic Interactions of Soil Humic Substances with Pesticides and Related Chemicals. Proc. Manitoba Soil Sci. Soc. Meeting, Winnipeg, MB, January 5-6.

G.R.B. Webster, M.H.K. Abdel-Kader, and L.P. Sarna. 1987. Comparative Study on the Distribution and Degradation of Malathion and Fenitrothion in Milled Fractions of Wheat Stored at Various Temperatures. 2nd Workshop on Chemistry and Fate of Organophosphorus Compounds. Barcelona, Spain. November 10-12.

K.J. Friesen, G.R.B. Webster, and D.C.G. Muir. 1987. Sunlight Photodegradation of 1,2,3,4,7-Pentachlorodibenzo-p-dioxins in Natural Water. 17th Annual Symposium in the Analytical Chemistry of Pollutants, Jekyll Is., GA, U.S.A. May 18-20.

G.R.B. Webster, L.P. Sarna, G.G. Choudhry, M.R. Servos, and D.C.G. Muir. 1987. Methods for Dissolving Hydrophobics for Studies of Solution Interaction with Dissolved Organic Matter. Symposium on the Influence of Aquatic Humic Substances on the Fate and Treatment of Pollutants, Divn. Environ. Chem., Amer. Chem. Soc., 193rd Nat. Mtg., Denver, CO, U.S.A., Apr. 5-10.

G.G. Choudhry and G.R.B. Webster. 1987. Nuclear magnetic resonance (NMR) spectroscopic characterization of several preparations of humic substances. Proceedings of the Symposium on "Influence of Aquatic Humic Substances on Fate and Treatment of Pollutants", eds. I.H. Suffet and P. MacCarthy, Div. Environ. Chem. of the Amer. Chem. Soc., 193rd ACS Nat. Meet., Denver, Colorado, U.S.A. April 5-10.

G.G. Choudhry, G.R.B. Webster, and O. Hutzinger. 1987. Environmental aquatic photochemistry of chlorinated aromatic pollutants (CAPs). Proceedings of the Third International Symposium on "Environmental Pollution and its Impact on Life in the Mediterranean Region", Istanbul, Turkey, September 1-4, 1985; Guest eds. H. Parlar et al., Pergamon Press New York.

G.G. Choudhry, J.A. van den Broecke, G.R.B. Webster, and O. Hutzinger. 1987. Environmental Photoincorporations of polychlorobenzenes into several humic model monomers. Proceedings of the Third International Symposium on "Environmental Pollution and its Impact on Life in the Mediterranean Region", Istanbul, Turkey, September 1-4, 1985; Guest eds. H. Parlar et al., Pergamon Press, New York.

G.G. Choudhry and G.R.B. Webster. 1987. Characterization of humic substances by 1H- and 13C-NMR. Proceedings of the 30th Annual Manitoba Soil Sci. Soc. Meeting, Winnipeg, MB, January 6-7, eds. J. Simons et al., Manitoba Agriculture, pp. 142-158.

T.C. Kuchnicki and G.R.B. Webster. 1987. The Effect of Trifluralin and TreflanTM on Anaerobic Nitrate and Nitrite Transformations. Proceedings of the 30th Annual Manitoba Soil Sci. Soc. Meeting, Winnipeg, MB, January 6-7, eds. J. Simons et al., Manitoba Agriculture, pp. 126 141.

M.R. Servos, D.C.G. Muir, and G.R.B. Webster. 1986. Bioavailability and Fate of Polychlorinated Dioxins in Lake Mesocosms. 7th Meeting of the Society of Environmental Toxicology and Chemistry, Alexandria, VA, U.S.A., November 2-5, Abst. #69.

G.R.B. Webster, L. Marcheterre, and D.C.G. Muir. 1986. Aquatic Environmental Fate of Octachlorodibenzo-p-dioxin in Ponds. 7th Meeting of the Society of environmental Toxicology and Chemistry, Alexandria, VA, U.S.A., November 2-5, Abstr. #85.

D.C.G. Muir, M.R. Servos, and G.R.B. Webster. 1986. Predicting Bioaccumulation of Hexa-, Hepta-, and Octachloro-dioxins in Aquatic Food Chains. 7th Meeting of the Society of Environmental Toxicology and Chemistry, Alexandria, VA, U.S.A., November 2-5, Abstr. #203.

G.G. Choudhry, and G.R.B. Webster. 1986. Environmental Aquatic Photochemistry of Some Tetra- through Octachlorodibenzo-p-dioxins: Quantum Yields and Sunlight Half-Lives. 69th Canadian Chemical Conference, Div. Agriculture: Environment, Saskatoon, SK, Canada, June 1-4.

G.G. Choudhry, and G.R.B. Webster. 1986. Environmental Aquatic Photochemistry of Polychlorophenols (PCPs). 6th International Congress of Pesticide Chemistry (IUPAC), Div. Environmental Fate, Ottawa, ON, Canada, August 10-15.

G.G. Choudhry, and G.R.B. Webster. 1986. Protocol Guidelines for the Investigations of Photochemical Fate of Pesticides in Water, Air, and Soils. 6th International Congress of Pesticide Chemistry (IUPAC), Div. Environmental Fate, Ottawa, ON, Canada, August 10-15.

B.F. Rordorf, L.P. Sarna, and G.R.B. Webster. 1985. Vapor Pressure Determination for Several Polychlorodioxins by Two Gas Saturation Methods. 5th International Symposium on Chlorinated Dioxins and Related Compounds, Bayreuth, Fed. Rep. Germany, September 16-19.

G.R.B. Webster, D.H. Muldrew, N.J. Graham, L.P. Sarna, and D.C.G. Muir. 1985. Dissolved Organic Matter Mediated Aquatic Transport of Chlorinated Dioxins. 5th International Symposium on Chlorinated Dioxins and Related Compounds. Bayreuth, Fed. Rep. Germany, September 16-19.

G.G. Choudhry, and G.R.B. Webster. 1985. Photochemical Quantum Yields and Sunlight Half-Lives of Polychlorodibenzo-p-dioxins in Aquatic Systems. 5th International Symposium on Chlorinated Dioxins and Related Compounds, Bayreuth, Fed. Rep. of Germany, September 16 19.

G.G. Choudhry, and G.R.B. Webster. 1985. Environmental Photochemistry of Polychlorinated Dibenzofurans (PCDFs) and Dibenzo-p-dioxins (PCDDs). A review. 5th International Symposium on Chlorinated Dioxins and Related Compounds, Bayreuth, Fed. Rep. Germany, September 16-19.

G.G. Choudhry, G.R.B. Webster, and O. Hutzinger. 1985. Environmental Aquatic Photochemistry of Chlorinated Aromatic Pollutants (CAPs). 3rd International Symposium on Environmental Pollution and Its Impact on Life in the Mediterranean Region, Istanbul, Turkey, September 1-4.

G.G. Choudhry, J.A. van den Broecke, G.R.B. Webster, and O. Hutzinger. 1985. Environmental Photoincorporations of Polychlorobenzenes into Several Humic Model Monomers. 3rd International Symposium on Environmental Pollution and Its Impact on Life in the Mediterranean Region, Istanbul, Turkey, September 1-4.

G.G. Choudhry, and G.R.B. Webster. 1985. Guidelines for the Studies of Photochemical Fate of Pesticides in Water, Air, and Soil. Proc. 20th Annual Western Canada Pesticide Residue Analysts' Workshop and 13th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Winnipeg, MB, Canada, May 7-9, pp. 78-86.

G.G. Choudhry, and G.R.B. Webster. 1985. Quantum Yields and Sunlight Half-Lives of Some Polychlorinated Dibenzo-p-dioxins (PCDDs) in Aquatic Systems. Proc. 20th Annual Western Canada Pesticide Residue Analysts' Workshop and 13th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Winnipeg, MB, Canada, May 7-9, pp. 121-125.

G.G. Choudhry, N.J. Graham, and G.R.B. Webster. 1985. Characterization of 2-Methyl-4,5,6,7-tetrachlorobenzoxazole formed during the Photolysis of Pentachlorophenol in Water-Acetonitrile Solution. Proc. 20th Annual Western Canada Pesticide Residue Analysts' Workshop and 13th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Winnipeg, MB, Canada, May 7-9, pp. 116-118.

K.J. Friesen, L.P. Sarna, and G.R.B. Webster. 1985. Determination of Physical Constants of Hydrophobic Chemicals for Purposes of Environmental Fate Modelling. Proc. 20th Annual Western Canada Pesticide Residue Analyst Workshop and 13th Workshop Meeting on the Chemistry and Biochemistry of Herbicides, Winnipeg, MB, Canada, May 7-9, pp.70-71.

G.G. Choudhry, and G.R.B. Webster. 1985. Quantum Yields of Polychlorodibenzo-p-dioxins (PCDDs) in Water-Acetonitrile Mixtures and Their Environmental Phototransformation Rates. Symposium on Aquatic Photochemistry, Div. Geochem. and Div. Environ. Chem. of the Amer. Chem. Soc., 189th ACS Nat. Meet., Miami Beach, Florida, U.S.A., April 28-May 3.

G.G. Choudhry, G.R.B. Webster, and O. Hutzinger. 1985. A Review of the Environmentally Significant Photochemistry of Chlorinated Benzenes and Their Derivatives in Aquatic Systems. Symposium on Aquatic Photochemistry, Div. Geochem. and Div. Environ. Chem. of the Amer. Chem. Soc., 189th ACS Nat. Meet., Miami Beach, Florida, U.S.A., April 28-May 3.

T.C. Kuchnicki, L.P. Sarna, and G.R.B. Webster. 1985. The Measurements of Nitrate and Nitrite in Soils by Reverse Phase HPLC. Proc. 28th Annual Manitoba Society of Soil Service Meeting, January 9-10, pp. 124-134.

G.R.B. Webster, D.H. Muldrew, N.J. Graham, F.J. Friesen, and D.C.G. Muir. 1985. Humic Substances Enhance Solubility of Chlorinated Dioxins in Water. 6th Annual Meeting of the Society of Environmental Toxicology and Chemistry, St. Louis, MO, U.S.A., November 10-13.

M.R. Servos, D.C.G. Muir, and G.R.B. Webster. 1985. The Effect of Dissolved Organic Matter on the Bioavailability of Chlorinated Dioxins to Fish. 6th Annual Meeting of the Society of Environmental Toxicology and Chemistry, St. Louis, MO, U.S.A., November 10-13.

G.G. Choudhry, and G.R.B. Webster. 1984. Environmental Photochemistry of Chlorophenols. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

G.G.Choudhry, and G.R.B. Webster. 1984. Interactions of Humic Substances with Herbicide-related Compounds. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24 25.

T.C. Kuchnicki, G.R.B. Webster, and C.M. Cho. 1984. Herbicides and Soil Nitrogen. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

D.C.G. Muir, A.E. Smith, A.L. Yarechewski, R.L. Corbet, and G.R.B. Webster. 1984. Final Results of Studies on the Persistence of 1,3,6,8-T4CDD in Soils and Sediments. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

R.L. Corbet, G.R.B. Webster, and D.C.G. Muir. 1984. The Significance of 1,3,6,8-Tetrachlorodibenzo-p-dioxin in an Aquatic System. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

B.P. Krawchuck and G.R.B. Webster. 1984. Movement of Pesticides to Groundwater in an Irrigated Soil. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

L. Marcheterre, G.R.B. Webster, and D.C.G. Muir. 1984. Fate of Octachlorodibenzodioxin, a Contaminant in Pentalchlorophenol in an Aquatic System. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

D.H. Muldrew, G.R.B. Webster, and C.M. Cho. 1984. Influence of Dissolved Organic Matter on Transport of Chlorinated Dioxins in Aqueous Solutions. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

K.J. Friesen, L.P. Sarna, P.E. Hodge, G.R.B. Webster, and D.C.G. Muir. 1984. Determination of Water Solubility and Octanol-Water Partition Coefficients of Chlorinated Dioxins. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

L.P. Sarna, P.E. Hodge, and G.R.B. Webster. 1984. Comparison of Several C18 Columns for Octanol-Water Partition Coefficients for Chlorinated Dioxins. Proc. 12th Workshop Chem. Biochem. Herbicides, Saskatoon, SK, April 24-25.

D.C.G. Muir, B.E. Townsend, and G.R.B. Webster. 1984. Aquatic Toxicity and Bioconcentration of Chlorinated Dioxins. 8th ASTM Aquatic Toxicology Symposium, Cincinati, OH, U.S.A., April 16-19.

G.R.B. Webster, L.P. Sarna, and D.C.G. Muir. 1983. Kow of 1,3,6,8-T4CDD and OCDD by Reverse Phase HPLC. 186th Meeting Amer. Chem. Soc., Environ. Chem. Divn., Washington, DC, U.S.A., August 28-September 2.

D.C.G. Muir, B.E. Townsend, and G.R.B. Webster. 1983. Bioavailability of [14C]1,3,6,8-Tetrachlorodibenzodioxin and [14C]Octachlorodibenzodioxin to Aquatic Insects in Sediment and Water. 186th Meeting Amer. Chem. Soc., Environ. Chem. Divn., Washington, DC, U.S.A., August 28-September 2.

G.R.B. Webster and M.H.K. Abdel-Kader. 1983. Analysis of Malathion and Fenitrothion and Metabolites in Stored Wheat. Proc. Canadian Pest Management Society, AIC National Convention, Truro, NS, July 10-14, pp. 10-14.

B.P. Krawchuk and G.R.B. Webster. 1983. Vertical Migration of Herbicides in an Irrigated Soil. Proc. 11th Workshop Chem. Biochem. Herbicides, Brandon, MB, April 19-20.

G.R.B. Webster and R.L. Corbet. 1983. Aquatic Fate of 1,3,6,8-T4CDD. Proc. 11th Workshop Chem. Biochem. Herbicides, Brandon, MB, April 19-20.

D.C.G. Muir, W.L. Lockhart, and G.R.B. Webster. 1982. Uptake and Clearance of [14C]1,3,6,8-Tetrachlorodibenzodioxin by Two Species of Fish. 3rd Ann. Meeting SETAC, Arlington, VA, U.S.A., November 14.

R.L. Corbet, D.C.G. Muir, and G.R.B. Webster. 1982. Fate of 1,3,6,8-TCDD in Aquatic System. 3rd International Symposium on Chlorinated Dioxins and Related Compounds, Salzburg, Austria, October 12-14.

G.R.B. Webster, G.P. Rawn, and D.C.G. Muir. 1982. Degradation and Fate of Permethrin in an Aquatic Ecosystem. 5th International Congress of Pesticide Chemistry (IUPAC), Kyoto, Japan, August 29-September 4.

L.P. Sarna, G.P. Rawn, and G.R.B. Webster. 1982. GLC and HPLC Analysis of 3,5,6-Trichloro-2-pyridinol Metabolite of Chlorpyrifos by Derivatization with Ethyl Chloroformate. 17th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Vancouver, BC, April 27-29.

B.S. Joia, S.R. Loschiavo, and G.R.B. Webster. 1982. Cypermethrin and Fenvalerate Residues in Stored Wheat. 17th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Vancouver, BC, April 27-29.

B.P. Krawchuk, L.P. Sarna, and G.R.B. Webster. 1982. Analysis of Irrigation Tile Drainage Water for Herbicide Residues. 10th Ann. Workshop Meeting Chem. Biochem. Herbicides, Regina, SK, April 5-6.

R.L. Corbet and G.R.B. Webster. 1982. Fate and Degradation of 1,3,6,8-TCDD in an Aquatic System. 10th Ann. Workshop Meeting Chem. Biochem. Herbicides, Regina, SK, April 5-6.

D.H. Muldrew, B.L. Worobey, and G.R.B. Webster. 1982. Adsorption of 2,4-D Related Compounds by Soil Organic Matter. 10th Ann. Workshop Meeting Chem. Biochem. Herbicides, Regina, SK, April 5-6.

G.R.B. Webster, and R.L. Corbet. 1982. Fate of the 2,4-D Contaminant 1,3,6,8-Tetrachlorodibenzo-p-dioxin in Aquatic Systems. 25th Ann. Manitoba Soil Sci. Mtg. Proc., Winnipeg, MB, January 11-12.

G.P. Rawn, D.C.G. Muir, and G.R.B. Webster. 1981. Uptake and Persistence of Permethrin by Fish, Vegetation, and Hydrosoil. 8th Ann. Aquat. Toxy. Workshop, Guelph, ON, November 2-4.

R.L. Corbet, and G.R.B. Webster. 1981. Fate of [14C]1,3,6,8-Tetrachlorodibenzo-p-dioxin (1368-TCDD) in a Model Pond System: Preliminary Results. 8th Ann. Aquat. Toxy. Workshop, Guelph, ON, November 2-4.

B.S. Joia, S.R. Loschiavo, and G.R.B. Webster. 1981. Efficacy and Persistence of Cypermethrin and Fenvalerate on Stored Wheat. Joint Mtg. Entomol. Socs. Alberta and Canada, Banff, AB, October 5-9.

L.P. Sarna, G.P. Rawn, and G.R.B. Webster. 1981. Analysis of Dursban (Chlorpyrifos) in Pond Water by HPLC. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30.

D.A. Birkholz, M.R. Samoiloff, W.F. Warwick, and G.R.B. Webster. 1981. Evaluation of an Analytical and Biological Testing Scheme for Detection of Biohazards: Tobin Lake Study. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30, and 6th AOAC Spring Workshop, Ottawa, ON, May 12-14.

B.S. Joia, S.R. Loschiavo, and G.R.B. Webster. 1981. Gas Chromatographic Determination of Cypermethrin and Fenvalerate Residues in Wheat. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30.

M.H.K. Abdel-Kader, and G.R.B. Webster. 1981. Method Development and Quantitative Determination of Malathion and Fenitrothion and Metabolites in Stored Grain. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30.

D.H. Muldrew, B.L. Worobey, and G.R.B. Webster. 1981. Volatilization losses of [14C]2,4,5,2',4',5'-Hexachlorobiphenyl from Solution and Glass Surfaces. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30.

R.L. Corbet, B.L. Worobey, G.R.B. Webster, W.F. Warwick, and D.A. Birkholz. 1981. Analysis and Confirmation of Polychlorinated Dibenzo-p-dioxins in Lake Sediments. 16th Ann. Pesticide Residue Analysts' Workshop, Western Canada, Winnipeg, MB, April 28-30.

A.E. Smith, B.L. Worobey, G.R.B. Webster, and M. Dudas. 1981. Impact of Agricultural Chemical Inputs. Workshop on Land Degradation, Alberta Soil Science, Edmonton, AB, February 25.

M.H.K. Abdel-Kader, and G.R.B. Webster. 1980. Translocation and Degradation of Malathion and Fenitrothion in Wheat Stored in Low Temperatures. Ent. Soc. Man., Winnipeg, MB, November 13-14.

G.P. Rawn, G.R.B. Webster, and D.C.G. Muir. 1980. Fate and Bioactivity of Permethrin for Biting Fly Control. Proc. 27th Annual Meeting Canadian Pest Management Society, Edmonton, AB, August 4-6.

v M.H.K. Abdel-Kader, and G.R.B. Webster. 1980. Influence of Temperature on the Stability and Translocation of Malathion and Fenitrothion in Stored Wheat. Proc. 27th Annual Meeting Canadian Pest Management Society, Edmonton, AB, August 4-6.

B.L. Worobey, and G.R.B. Webster. 1980. A de novo Theory of Xenobiotic Binding to Soil: A Mechanistic Approach. 8th Workshop Chem. Biochem. Herbicides, Regina, SK, April 28-29.

B.L. Worobey, and G.R.B. Webster. 1980. Studies on the Release of "Bound" 4-Chloraniline Residues from Soils and Soil Humic Acids. 8th Ann. Workshop Chem. Biochem. Herbicides, Regina, SK, April 28-29.

G.P. Rawn, D.C.G. Muir, and G.R.B. Webster. 1980. Fate of Permethrin in an Aquatic Ecosystem. 15th Ann. Pesticide Residue Analysts' Workshop, Regina, SK, April 20 - May 2.

M.H.K. Abdel-Kader, and G.R.B. Webster. 1980. Low Temperature Degradation and Translocation of Malathion and Fenitrothion in Stored Wheat. 15th Annual Pesticide Residue Analysts' Workshop, Regina, SK, April 30-May 2.

v B.L. Worobey, and G.R.B. Webster. 1979. Elucidation of Pesticide Residue Interaction with Soil Humic Acids. Proc. 23rd Ann. Man. Soil Sci. Mtg., Winnipeg, MB, December 5-6:43-58.

G.P. Rawn, D.C.G. Muir, and G.R.B. Webster. 1979. Bioavailability and Fate of the Synthetic Pyrethroid Larvicide Permethrin. Proc. 23rd Ann. Man. Soil Sci. Mtg., Winnipeg, MB, December 5-6: 59-66.

G.P. Rawn, G.R.B. Webster, and D.C.G. Muir. 1979. Bioavailability and Persistence of Permethrin as a Mosquito Larvicide in Artificial Pools. Man. Ent. Soc. Mtg., Winnipeg, MB, November 8-9.

G.R.B. Webster, and B.L. Worobey. 1978. In Vitro Cleavage of Pesticidal Mono- and Di-substituted Ureas during Derivatization with Trifluoroacetic Anhydride. Abstracts 4th Internat. Congress Pestic. Chem. (IUPAC), VI-729, Zurich, Switzerland, July 24-28.

G.R.B. Webster, B.L. Worobey, and L.P. Sarna. 1978. Analysis of MCPA and 2,6-Difluorobenzoic Acids in Waters as Their Pentafluorobenzyl Derivatives. 6th Workshop Mtg. Chem. Biochem. of Herbicides, Regina, SK, April 10-11.

G.P. Rawn, G.M. Findlay, and G.R.B. Webster. 1977. The Bioavailability of Dursban in Water Pools. Ent. Soc. Canada/Ent. Soc. Manitoba, Joint Meeting, Winnipeg, MB, August 22-24.

G.W.K. Mensah, F.L. Watters, and G.R.B. Webster. 1977. Translocation of Organophosphorus Insecticides into Stored Grain from Treated Surfaces of Storage Containers. Proc. Canadian Pest Management Society, Guelph, ON, August 15-18.

L.P. Sarna and G.R.B. Webster. 1977. GLC Analysis of Methoprene and Primary Metabolites in Pond Water. Proc. 12th Annual Pesticide Residue Analysts' Workshop for Western Canada, Winnipeg, MB, May 10-12.

B.L. Worobey and G.R.B. Webster. 1977. In Vitro Degradation of Dimilin during Derivatization with Perfluoroanhydrides. Proc. 12th Annual Pesticide Residue Analysts' Workshop for Western Canada, Winnipeg, MB, May 10-12.

D.A.J. Murray and G.R.B. Webster. 1977. Analysis of Trace Organic Contaminants in Water. Proc. 12th Annual Pesticide Residue Analysts' Workshop for Western Canada, Winnipeg, MB, May 10-12.

G.P. Rawn, G.M. Findlay, and G.R.B. Webster. 1977. The Effect of Bottom Substrates on Chlorpyrifos Residues in Pond Water. Proc. 12th Annual Pesticide Residue Analysts' Workshop for Western Canada, Winnipeg, MB, May 10-12.

G.J. Reimer and G.R.B. Webster. 1977. Mathematical Modelling of Pesticide Degradation in Soil. Proc. 12th Annual Pesticide Residue Analysts' Workshop for Western Canada, Winnipeg, MB, May 10-12.

G.R.B. Webster, C.F. Shaykewich, S. Kanhai, and G.J. Reimer. 1976. Soil Factors Affecting Degradation and Residual Weed Control of Treflan. Proc. Manitoba Agronomists' Conference, Winnipeg and Brandon, MB, December 14-15.

G.R.B. Webster. 1976. Mosquito Larvicide Residue Analysis in Glenlea Pond Water. Analysis of the Chitin Inhibitor Dimilin by GLC. Chemical Institute of Canada Symposium on Water Quality Chemistry, Winnipeg, MB, April 28.

B.L. Worobey and G.R.B. Webster. 1976. Determination of 1-(4-Chlorophenyl)-3-(2,6-difluorobenzoyl) Urea (Dimilin, TH6040) Residues in Pond Water by GLC. 11th Annual Pesticide Residue Analysts' Workshop for Western Canada, Saskatoon, SK, May 10-12.

L.P. Sarna and G.R.B. Webster. 1976. A Method for the GC Analysis of Altosid in Water. 11th Annual Pesticide Residue Analysts' Workshop for Western Canada, Saskatoon, SK, May 10-12.

G.J. Reimer and G.R.B. Webster. 1976. Chemical Derivatives of Dursban Metabolites. 11th Annual Pesticide Residue Analysts' Workshop for Western Canada, Saskatoon, SK, May 10-12.

G.R.B. Webster and C.F. Shaykewich. 1975. The Herbicide Trifluralin (Treflan): Factors Affecting Bioavailability and Degradation of Residues in Four Manitoba Soils. Proc. 19th Annual Manitoba Soil Science Meeting, Winnipeg, MB, December 10-11. pp. 74-81.

L.P. Sarna, G.R.B. Webster, G.J. Howe, and G.M. Findlay. 1975. Simultaneous Gas Chromatographic Analysis of Dimethoate and Several Metabolites by Derivatization. Proc. 10th Annual Pesticide Residue Analysts' Seminar for Western Canada, Edmonton, AB, May 12-14.

G.R.B. Webster. 1975. Degradation of Pesticide Residues in Samples Awaiting Analysis: Assessment and Methods for Adjustment of Results. Proc. 10th Annual Pesticide Residue Analysts' Seminar for Western Canada, Edmonton, AB, May 12-14.

G.R.B. Webster and G.J. Reimer. 1975. Cold Storage Degradation of the Herbicide Metribuzin (Sencor) in Field Samples Awaiting Analysis. Proc. 10th Annual Pesticide Residue Analysts' Seminar for Western Canada, Edmonton, AB, May 12-14.

L.P. Sarna and G.R.B. Webster. 1974. The Coulson Conductivity Detector for Nitrogen Compounds. A Maintenance Program enabling GLC Analysis of Herbicides in Crude Soil Extracts. Proc. 9th Annual Pesticide Residue Analysts' Seminar for Western Canada. Vancouver, BC, May 29-30. pp. 188-197.

G.R.B. Webster and G.J. Reimer. 1974. Degradation of the Herbicide Sencor in a Canadian Prairie Soil. Quantitative Examination of Metabolites. 2nd Annual Meeting on the Chemistry and Biochemistry of Herbicides. Regina, SK, March 4-5.

G.R.B. Webster. 1974. Report on University Research on Pesticides. Work Planning Meeting, Research Branch, Agriculture Canada, Pesticide Chemistry, Ottawa, ON, January 15-16.

G.R.B. Webster, L.P. Sarna, and S.R. Macdonald. 1973. Nonbiological Degradation of Sencor in Manitoba Soils. Proc. Agricultural Pesticides Society (AIC), Victoria, BC, August 20-23. pp. 30 37.

G.R.B. Webster and S.R. Macdonald. 1973. Simultaneous GLC Analysis of Sencor and its Major Metabolites. Proc. 8th Annual Pesticide Residue Analysts' Seminar for Western Canada. Winnipeg, MB, May 23-24, 1973. pp. 126-135.