Technological hazards to environmental systems and human health are a growing problem for industrialized societies. The increasing size and complexity of activities involving hazardous substances (CAS numbers have just recently surpassed the 1,000,000 mark) requires higher emphasis on the assessment and management of technological risk.
Another dimension is the inclusion of environmental considerations. Risk assessment traditionally often concentrates on human fatality risk, and sometimes property damage. There is, however, increasing interest in including environmental consequences into a truly multi-criteria risk assessment. The consequences of, for example, spills of toxic material for surface and groundwater bodies can induce some long-term damage, and the clean-up costs can be staggering. The same holds true for oil spills, as recent examples clearly show. Evaluation in terms of the cost of repair is a well established concept in environmental economics. It is however, the irreversible damages to ecosystems that again introduce the multi-criteria problem of evaluation.
To minimize risk, both to human health and property, as well as to the natural environment, various types of information from different sources are needed quickly for further processing, analysis, and interpretation, both in a regulatory as well as in a risk management framework. People in government and industry, responsible for planning, managing, and regulating hazardous operations and substances need tools that bring to bear the best available science and information. Advanced information technology can help to provide this information in a timely and directly useful format.
The availability of affordable computers, as well as new technologies such as expert systems, interactive modeling, and high resolution, dynamic computer graphics now make it possible to build powerful, accessible, and easy to use information and decision support systems for risk assessment and risk communication.
Since 1985 IIASA's Advanced Computer Applications (ACA) group has developed several software systems dealing with technological risk assessment. The first system, developed for the Commission of the European Communities' Joint Research Centre in Ispra, Italy, was a prototype for use within the regulatory framework of the EC's Seveso Directive (CEC 1982) and related legislation. This system was the starting point for several other projects, including XENVIS (X-based Environmental Information System), developed for the Dutch Ministry of Housing, Physical Planning, and the Environment.
XENVIS integrates a national level geographical information system (GIS) with several interlinked data bases, in particular on hazardous substances and hazardous industrial installations, with emphasis on those in the so-called Seveso-class, ie., installations that fall under the provisions of the seveso Directive. GIS and data bases are linked to simulation models for industrial air pollution, toxic spills to surface water, ie., the Rhine-Maas system, and rail and road transportation problems. The graphical user interface incorporates a context sensitive hypertext help- and explain system, and embedded expert system components that can assist users in scenario specification, parameter estimation, and the interpretation and further analysis of model results or plant specific safety data including safety audits. XENVIS also serves as a pre- and post-processor for a major fault- and event tree risk assessment package, incorporating its results, eg., as risk contours around a plant, in the data bases and displaying them at the GIS level.
XENVIS is designed to support the Ministry's risk management tasks, within the framework of national and European legislation. Other related models include transportation risk analysis, eg, in a case study of the Haute Normandie (Lassare, et al. 1993, Weigkricht and Fedra, 1993); or the modeling of groundwater contamination from spills or land fills of hazardous waste (Fedra et al., 1995) The system's architecture, components, and uses are described in this paper.