BETR North America: A regionally segmented multimedia contaminant fate model for North America

Abstract

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.

BETR global – A geographically-explicit global-scale multimedia contaminant fate model

“…The fugacity concept is described in detail by Mackay (2001), and the general structure of models based on the BETR framework is described by MacLeod et al (2001). The BETR Global parameterization of the framework describes the global environment on a 15 o × 15 o grid as a set of 288 multimedia regions linked by flows of air and water.…”

Chemical-Specific Representation of Air−Soil Exchange and Soil Penetration in Regional Multimedia Models

“…Compartment models for soil columns that are compatible with existing multimedia fate models must account for air-soil exchange, storage and transformation in soil, and in some cases transport to shallow ground water (2,4,8,(27)(28)(29). While there are a number of mathematical algorithms (9,11,22,25,26) available to solve the differential equations describing the transport and transformation of pollutants within soil, multimedia models rarely require this level of detail.…”

Soil Contamination and Human Health: A Major Challenge for Global Soil Security

“…example presented in Figure 10.2) which provide appropriate quantitative frameworks for evaluating the complex interactions between chemicals and the environment (Caudeville et al, 2012) can be used for assessing exposure. These models can be spatialized (Caudeville et al, 2012;MacLeod et al, 2001;Feijtel et al, 1997), or not (Bonnard and McKone, 2010). They can also be integrated with PhysicologicallyBased Pharmaco-Kinetics models for assessing the uptake impact of a contaminant directly on a target tissue at individual levels (Maurau et al, 2011).…”