|
(125) Multimedia modelling of phthalate esters using the Industrialised World Model. Cousins, Ian1, Mackay, Donald1, 1 ABSTRACT- The objective of this study was to develop a multimedia mass balance model, which reconciles the observed environmental concentrations of five phthalate esters with reported emission rates. A satisfactory reconciliation has several benefits. It indicates that the emissions are fully accounted for, that the dominant fate processes (including degradation rates) are in accord with model predictions and it gives a method by which any future changes in emission rate can be translated into a time course of concentration changes. To accomplish this, a novel approach was taken, which is regarded as intermediate between the use of a region-specific model and a purely evaluative model. The model, known as the Industrial World Model, was parameterized to represent an industrially developed region typical of Western Europe or parts of North America. No attempt was made to validate the model against actual concentration data from a specific region, rather model predicted concentrations were reconciled with observed values from regions of similar population density. This has the advantage that it permits a larger database of concentrations to be used. Emission rates for the phthalate esters were estimated on a per capita basis, since their consumption per capita is believed to be fairly constant. The model was run in steady state mode and predicted concentrations were compared to observed concentrations in the primary environmental media of air, water, soil and sediments, which were extracted from a recently compiled extensive monitoring database. Predicted concentrations were shown to generally consistent with observed values. The model was also run in unsteady state mode to predict the fate of phthalates from their introduction into commerce until the present and to estimate future trends of phthalates in the environment. Key words: phthalate ester, multimedia, model, mass balance |
