Assessment of Chemical Fate in the Environment Using Evaluative, Regional and Local-Scale Models: Illustrative Application to Chlorobenzene and Linear Alkylbenzene Sulfonates

Abstract

Abstract-Evaluation of chemical fate in the environment has been suggested to be best accomplished using a five-stage process in which a sequence of increasing site-specific multimedia mass balance models is applied. This approach is illustrated for chlorobenzene and linear alkylbenzene sulfonates (LAS). The first two stages involve classifying the chemical and quantifying the emissions into each environmental compartment. In the third stage, the characteristics of the chemical are determined using the evaluative equilibrium criterion model, which is capable of treating a variety of chemicals including those that are involatile and insoluble in water. This evaluation is conducted in three steps using levels I, II, and III versions of the model, which introduce increasing complexity and more realistic representations of the environment. In the fourth stage, ChemCAN, which is a level III model for specific regions of Canada, is used to predict the chemical's fate in southern Ontario. The final stage is to apply local environmental models to predict environmental exposure concentrations. For chlorobenzene, the local model was the SoilFug model, which predicts the fate of agrochemicals, and for LAS the WW-TREAT, GRiDS, and ROUT models were used to predict the fate of LAS in a sewage treatment plant and in riverine receiving waters. It is concluded that this systematic approach provides a comprehensive assessment of chemical fate, revealing the broad characteristics of chemical behavior and quantifying the likely local and regional exposure levels.

Sources and mass fluxes of the main contaminants in a heavily polluted and modified river of the North China Plain

“…Most mass balance models were developed for nonionizing organic chemicals and metals (Lessard et al 2013;Mackay et al 1996;Peters et al 2006). For some pollutants such as COD and NH 4 -N, there are more challenges because they are chemically and biologically reactive.…”

Guidance Document on the Use of Multimedia Models for Estimating Overall Environmental Persistance and Long-Range Transport

“…At a smaller scale (national to continental), ChemCAN is a generic Level III fugacity model with the addition of a database of environmental parameters for 24 ecological regions of Canada (Mackay et al 1996). ChemCAN has been evaluated for a limited number of contaminants in the southern Ontario, Canada region (MacLeod et al, 1999) and has also been applied in Japan (Kawamoto et al, 2001).…”

Guidance on the Selection of Efficient Computational Methods for Multimedia Fate Models

“…Most of the initial MFMs 1,2 were based on the definition of well mixed standard compartments, such as air, soil, water and sediment, and were simple steady state partitioning models with a fixed environmental scenario. [3][4][5][6] Many MFMs then evolved towards unsteady state or dynamic systems, 7 also used to study the behaviour of persistent organic pollutants at a global level. 8,9 The number of compartments also increased as the original four were often subdivided into a number of boxes (e.g.…”