Efraim Halfon - Simulation models

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These publications deal with the development of eutrophication models, fate models and the eventual development of TOXFATE. The world is impacted by the presence of about 50,000 toxic contaminants. Systems ecologists, like myself, want to predict the fate of these substances, once they enter the water environment. Tools used to obtain these predictions are computers, both mainframe and micros, mathematical equations, usually differential equations, and field observations, data usually collected by other scientists. The numerical solution of these equations is called a simulation, i.e. we replicate the real world inside a computer.

Halfon, E. and Lam, D.C.L., 1978. The effects of advection-diffusion processes on the eutrophication of large lakes, a hypothetical example: Lake Superior. Ecological Modelling, 4:119-131.

Lam, D.C.L. and Halfon, E. 1978. Model of primary production including circulation influences in Lake Superior. Applied Mathematical Modelling, 2:30-40.

Simons, T.J., Boyce, F.M., Fraser, A.S., Halfon, E. Hyde, D., Lam, D.C.L., Schertzer, W.M., El-Shaarawi, A.H., Willson, K., and Warry, D., 1979. Assessment of water quality simulation capability for Lake Ontario. Scientific Series No. 111, Inland Waters Directorate, Environment Canada, 220 pp.

Halfon, E., 1979. The effects of data variability in the development and validation of ecosystem models. In: B.G. Zeigler, M.S. Elzas, G.J. Klir and T.I. Oren, (Eds.) Methodology in Systems Modelling and Simulation, North Holland Publishing Company, pp. 335-343.

Halfon, E., 1979. Computer-based development of large scale ecological models: problems and prospects. In: G.S. Innis and R.V.O'Neill (Eds.) Systems Analysis of Ecosystems, International Co-operative Publishing House, Burtonsville, Maryland, PP- 197-209.

Halfon, E., 1980. The current status and future of systems ecology: a personal view. INTECOL Bulletin, 7/8:30-32.

Halfon, E. and Maguire, R.J. 1981. Distribution et transformation du Fenitrothion Spandu sur un etang: modelisation dans des conditions d'incertitude. Eau du Quebec, 14: 216-220.

Schom, C.B. and Halfon, E. 1982. Kin selection as a salmonid survival strategy explaining mortality and variable growth in families: a modeling study. J. Theor. Biol., 94: 153-172.

Halfon, E. 1983. Organic contaminants fate model for the prediction of transient water quality in the Niagara River plume, Lake Ontario. NWRI, Report #83-3, Environment Canada, 82 pp.

Halfon, E., 1984. Modelling the fate of toxic contaminants in the Niagara River and Lake Ontario. NWRI, Report #84-39, Environment Canada, 103 pp.

Halfon, E. 1984. The composition of particulate matter in the euphotic zone of Lake Superior. J. Great Lakes Research, 10: 299-306.

Halfon, E., 1986. Modelling the fate of Mirex and Lindane off the Niagara River mouth. Ecological Modelling, 33: 13-33.

Halfon, E., 1986. Modelling the pathways in the St. Clair-Detroit River system using the TOXFATE model: The fate of Perchloroethylene. Water Pollution Journal of Canada, 21: 411-421.

Halfon, E., 1987. The feasibility of modelling the fate of organics and heavy metals in the Yamaska River watershed before and after the construction of car assembly plant near Bromont, Quebec.

Halfon, E., 1987. Modelling of Mirex loadings to the bottom sediments of Lake Ontario within the Niagara River plume. J. Great Lakes Res., 13: 18-23.

Halfon, E. 1989. The application of ecological modelling to toxic contaminants and ecosystem stress. Water Poll. Res. J. Canada, 24:323-343.

Halfon, E. and Brüggemann, R. 1990. Simulation of disulfoton fate in the River Rhine with the TOXFATE model, Sci. Tot. Environ., 97: 385-394.

Halfon, E., T.J. Simons and W.M. Schertzer. 1990. Modelling the spatial distribution of seven halocarbons in Lake St. Clair in June 1984 using the TOXFATE model. J. Great Lakes. Res., 16:90-112.

Halfon, E. and Poulton, D. 1992. Distribution of Chlorobenzenes, Pesticides and PCB Congeners in Lake Ontario near the Toronto Waterfront. Water Poll. Res. J. Canada, 27: 751-772.

Millard, E.S., Halfon, E., Minns. C.K., and Charlton, C.C. 1993. Effect of primary productivity and vertical mixing on PCB dynamics in planktonic model ecosystems. Environ. Toxicol. Chemistry, 12: 931-946.

Halfon, E. and Allan, R.J. 1995. Modelling the fate of PCBs and Mirex in aquatic ecosystems using the TOXFATE model. Environment International, 21: 557-569.

Halfon E., N. Schito and R. E. Ulanowicz. 1996. Energy flow through the Lake Ontario food web: Conceptual model and an attempt to mass balance, Ecological Modelling, 86:1-36.

Halfon, E. 2001.Impact on the Fate of Toxic Contaminants in the Toronto Waterfront - Should the Toronto Main Sewage Treatment Plant Outfall Be Moved Farther Offshore? Water Quality Research Journal of Canada, 36: 21-42.

Halfon, E. and Maguire, R.J. 1983. Distribution and transformation of Fenitrothion sprayed on a pond: Modelling under uncertainty. In M.B. Beck and G. van Straten (Eds.) Uncertainty and Forecasting of Water Quality. Springer-Verlag, Berlin and New York, 117-128.

Halfon, E., 1987. Hierarchical modelling in ecology. In. M.G. Singh and 23 other editors Systems and Control Encyclopaedia, Pergamon Press, London, p. 1329.

Halfon, E., 1987. Mathematical models in ecology. In M.G. Singh and 23 other editors Systems and Control Encyclopaedia, Pergamon Press, London, 1323-1324.

Halfon, E., 1987. Temperature model formulation in ecological modelling. In. M.G. Singh and 23 other editors Systems and Control Encyclopaedia, Pergamon Press, London, p. 1333.

Halfon, E. 1989. Modelling the fate of toxic contaminants in the aquatic environment: A review. In Aquatic Toxicology, E. Boudou and F. Ribeyre, Eds. CRC Press, 258-274.

Halfon, E. and Oliver, B.G. 1990. Simulation and data analysis of four chlorobenzenes in a large lake system (Lake Ontario) with TOXFATE, a contaminant fate model. In: S.E. Jorgensen (Ed.) Modelling in Ecotoxicology, Elsevier, pp. 197-214.

Halfon, E. 1991. Fate of toxic contaminants in lakes: development and calibration of TOXFATE (Version 3.6). NWRI Report.

Halfon, E. and Schito, N. 1993. In search of a realistic Lake Ontario food web. In V. Christensen and D. Pauly (Eds.) Trophic models of aquatic ecosystems. Publishers: ICLARM Conference Proceedings No. 26. International Center for Living Aquatic Resources management, Manila, Philippines; International Council for the Exploration of the Sea, Copenhagen, Denmark; and, Danish International Development Agency, Copenhagen, Denmark, 29-39.

Halfon, E. and N. Schito. 1993. Organic contaminants in Lake Ontario, 1968-1991. A Review and a data base. In Reducing uncertainty in mass balance models of toxics in the Great Lakes - Lake Ontario Case Study, Donald W. Rennie Memorial Monograph Series, No. 4, pp. 235-285.

Halfon, E. 1993. Ecological Modelling. In P.C. Young (Ed.), Concise Encyclopaedia of Environmental Systems, Pergamon Press., pp. 174.

Halfon, E. 1993. Lotka -Volterra Population Models. In P.C. Young (Ed.), Concise Encyclopaedia of Environmental Systems, Pergamon Press., pp. 354.

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