HAZARD: An Expert System for Risk Assessment of Environmental Chemicals

Abstract

The purpose of this paper is to report on an expert system in design that screens for potential hazards from environmental chemicals on the basis of structure-activity relationships in the study of chemical carcinogenesis, particularly with respect to analyzing the current state of known structural information about chemical carcinogens and predicting the possible carcinogenicity of untested chemicals. The structure-activity tree serves as an index of known chemical structure features associated with carcinogenic activity. The basic units of the tree are the principal recognized classes of chemical carcinogens that are subdivided into subclasses known as nodes according to specific structural features that may reflect differences in carcinogenic potential among chemicals in the class. An analysis of a computerized data base of known carcinogens (knowledge base) is proposed using the structure-activity tree in order to test the validity of the tree as a classification scheme (inference engine).

Die Arbeit berichtet über ein in Entwicklung befindliches Expertensystem zur Ermittlung eventueller Gefährdungen durch Umweltchemikalien auf der Basis von Struktur-Aktivitäts-Beziehungen beim Studium der chemischen Karzinogenese, speziell im Hinblick auf die Analyse der derzeit bekannten Informationen über die Struktur chemischer Karzinogene und die Voraussage einer möglichen Karzinogenität noch ungetesteter Chemikalien. Der Struktur-Aktivitäts-Baum dient als Index von bekannten chemischen Struktureigenschaften und karzinogener Aktivität. Die Grundeinheiten dieses Baumes sind die wesentlichsten bekannten Klassen chemischer Karzinogene, die unterteilt werden in Unterklassen von Knoten entsprechend bestimmten strukturellen Eigenschaften, die Unterschiede bezüglich des karzinogenen Potentials der Stoffe innerhalb der gleichen Klasse widerspiegeln können. Eine Analyse einer computergespeicherten Datensammlung von bekannten Karzinogenen wird vorgeschlagen, die unter Benutzung des Struktur-Aktivitäts-Baumes die Brauchbarkeit des Baumes als Klassifikationsschema testen soll.

Key-Words

Expert System - Risk Assessment - Chemical Carcinogenesis - Environmental Chemicals

Schlüssel-Wörter

Expertensystem - Risikoabschätzung - chemische Karzinogenese - Umweltchemikalien

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