Keywords
risk assessment, simulation modelling, discrete mathematics, hasse diagram technique, posets, whasse software
Start Date
1-7-2006 12:00 AM
Abstract
The evaluation of the potential risk of chemicals receives again a lot of interest due to the renewed chemicals’ policy in the EU. The model package E4CHEM (Exposure Estimation for Potentially Ecotoxic Environmental Chemicals), already developed 1984-1992, is presented in this paper. This is a model which on the one side needs less information or input parameters as the often applied EUSES (European Union System for the Evaluation of Substances) and on the other side provides modules, like EXWAT (Model for the behaviour of the chemical in rivers)) and DTEST (Automatic Data Estimation), which as such are not contained in EUSES. The software package E4CHEM does not comprise the modern software techniques as the more recently developed model EUSES, however it follows the general ideas of model supported evaluation. In contrast to the well-known software-program GREAT-ER which allows a geo-referenced risk assessment of chemicals, the simpler module EXWAT is used to obtain fate descriptors, based on the behaviour of chemicals in one river segment. By the fate descriptors a partial order is defined and evaluated by the DELPHI-program WHASSE. In the resulting digraph the chemicals are considered as vertices and the order relation as arcs, connecting (after a transitive reduction) the vertices. It is shown that the resulting directed graph can be separated into subposets which are associated with a specific behaviour of the chemicals.
Structure - Fate - Relationships of Organic Chemicals
The evaluation of the potential risk of chemicals receives again a lot of interest due to the renewed chemicals’ policy in the EU. The model package E4CHEM (Exposure Estimation for Potentially Ecotoxic Environmental Chemicals), already developed 1984-1992, is presented in this paper. This is a model which on the one side needs less information or input parameters as the often applied EUSES (European Union System for the Evaluation of Substances) and on the other side provides modules, like EXWAT (Model for the behaviour of the chemical in rivers)) and DTEST (Automatic Data Estimation), which as such are not contained in EUSES. The software package E4CHEM does not comprise the modern software techniques as the more recently developed model EUSES, however it follows the general ideas of model supported evaluation. In contrast to the well-known software-program GREAT-ER which allows a geo-referenced risk assessment of chemicals, the simpler module EXWAT is used to obtain fate descriptors, based on the behaviour of chemicals in one river segment. By the fate descriptors a partial order is defined and evaluated by the DELPHI-program WHASSE. In the resulting digraph the chemicals are considered as vertices and the order relation as arcs, connecting (after a transitive reduction) the vertices. It is shown that the resulting directed graph can be separated into subposets which are associated with a specific behaviour of the chemicals.
