We present the Berkeley-Trent North American contaminant fate model (BETR North America), a regionally segmented multimedia contaminant fate model based on the fugacity concept. The model is built on a framework that links contaminant fate models of individual regions, and is generally applicable to large, spatially heterogeneous areas. The North American environment is modeled as 24 ecological regions, within each region contaminant fate is described using a 7 compartment multimedia fugacity model including a vertically segmented atmosphere, freshwater, freshwater sediment, soil, coastal water and vegetation compartments. Inter-regional transport of contaminants in the atmosphere, freshwater and coastal water is described using a database of hydrological and meteorological data compiled with Geographical Information Systems (GIS) techniques. Steady-state and dynamic solutions to the 168 mass balance equations that make up the linked model for North America are discussed, and an illustrative case study of toxaphene transport from the southern United States to the Great Lakes Basin is presented. Regionally segmented models such as BETR North America can provide a critical link between evaluative models of long-range transport potential and contaminant concentrations observed in remote regions. The continent-scale mass balance calculated by the model provides a sound basis for evaluating long-range transport potential of organic pollutants, and formulation of continent-scale management and regulatory strategies for chemicals.

Ongoing deliberations on the regulation of semivolatile organic chemicals require the assessment of chemical transport in atmospheric and marine systems. The characteristic travel distance was proposed as a measure for the transport potential in air and water. However, the existing definition treats the transport processes separately. It is shown that combined transport in coupled air-ocean systems can accelerate the overall transport into remote regions. Concentration ratios in air and water change with distance from sources depending on the initial concentration ratio and on the difference between the transport velocities. A measure is suggested facilitating the chemical screening with respect to transport potentials in such air-ocean systems. A case study for α and γ-hexachlorocyclohexane shows that the suggested measure qualitatively reveals the transport potentials of these chemicals and exemplifies possible concentration patterns.

This book provides a review and guide to environmental policy options for the control of agricultural pollution (particularly water pollution) and the economic, administrative and political merits of such policies. The principal focus is on the developed world, particularly North America and Europe. The book covers: the issues concerning agriculture and water quality; the voluntary and indirect approaches for reducing externalities and satisfying multiple objectives; the estimation of the benefits and costs of pollution control policies; the pollution control policies in the USA and EU; and the decomposition of the effects of trade on the environment. The book contains 7 chapters and a subject index.

The incentives and approaches for modelling chemical fate at a continental scale are discussed and reviewed. It is suggested that a multi-media model consisting of some 20–30 regions, each of which contains typically seven environmental compartments represents a reasonable compromise between the issues of the need for detailed resolution, avoidance of excessive data demands and inherent complexity and transparency. Strategies adopted in compiling the Berkley-Trent (BETR) model for North America are discussed and used to illustrate the issues of selecting appropriate number and nature of segments, treatment of air and water flows and the acquisition of environmental data. It is suggested that GIS software can play a valuable role in gathering and processing such data and in the display and interpretation of the results of the model assessment. The BETR model will be a useful tool for describing the nature of persistence and long-range transport of chemicals of concern in the North American environment.

Papers on Malaysia -- Thailand -- Australia.

From the 86 oral and poster papers originally presented, 28 papers have been selected for these proceedings. They are in seven focus areas: urban issues; watershed analysis; agriculture and forestry; groundwater; modeling analysis and application; policy consideration; and application of geographic information systems.

Athabasca Oil Sands are found in the McMurray formation in the Athabasca River Basin in Northern Alberta, Canada. Monitoring studies conducted during 1998-1200, have indicated that there is a preponderance of oil sands-derived hydrocarbons, primarily PAHs, their C14 alkylated analogues, and biomarkers, in downstream sediment samples of the tributaries relative to the upstream samples. The relative composition of these hydrocarbons are diagnostic of a petrogenic source, and provides a fingerprint for characterization of biofilm samples, aquatic invertebrates, and sediments in northern rivers and tributaries. Results of GC-MS analyses of sediments, confirm that the tributaries passing through the Fort McMurray oil sands regions contain significant levels of naturally derived hydrocarbons (2-50 mg/g). Field activities in heavily impacted areas should therefore continue to emphasize the tributaries draining through oil sands deposits, as opposed to the main-stem of the Athabasca River where hydrocarbon levels are subject to dilution from high sedimentation rates.