Exposure to combinations of substances: a system for assessing health risks.

Combined exposures may be categorised as specified combinations or mixtures of substances, depending on composition and exposure scenario. The major characteristic of a specified combination is known composition and that of a mixture simultaneous exposure. A framework was developed as a guide for safety evaluation of combined exposures.

International issues on human health effects of exposure to chemical mixtures.

In this article, we highlight new developments and recent studies concerning adverse human health effects related to chemical mixtures. One group of activities comprises the development of a new computer program for analyzing mixture studies and a mathematical model as a basis for combination rules that predict the toxicity of mixtures. Other new activities in the area of experimental studies are the application of gene expression technologies in mixture research, and pattern recognition as a tool in safety evaluation of complex mixtures.