RATIONAL RANKING OF CHEMICALS ACCORDING TO ENVIRONMENTAL RISK - AN ILLUSTRATION USING MULTIVARIATE BIOLOGICAL PROFILING OF HALOGENATED ALIPHATIC-HYDROCARBONS

This paper discusses an often overlooked step in environmental quantitative structure-activity relationship analysis, the multivariate profiling of the biological effects of chemicals. In order to span as many aspects as possible of the biological effects of environmental chemicals, biological measurements should be conducted in a multitude of test systems, on several animal species, at various dose levels, etc., to ensure that the multivariate response data matrix contains as much information as possible. This profiling is illustrated with chemicals belonging to the class of halogenated aliphatic hydrocarbons. A small set of ten representative compounds has been multivariately profiled by twelve biological response variables. These data are analyzed and interpreted with principal component analysis. This provides a check of the biological similarity of the chemicals and may be used to identify dissimilar compounds with deviating biological effects. The principal component loadings show how the biological responses relate to each other, and which biological tests give the same information. A discussion is presented of how this type of analysis can be used in the risk assessment of environmental chemicals.