Chemical and Physical Agent Interaction

Abstract

This chapter, concerning interactions at simultaneous or successive exposure to both physical and chemical factors, focuses on the industrial environment. Examples of this kind of interaction can probably be found in a large variety of totally different and unrelated areas, and the present text is not intended to be a complete review but to present illustrative examples of studies and occupational areas in which such interactions are included. Reported findings are of both physicochemical and biological nature, most often descriptive observations, and referred papers rarely include mechanistic information or hypotheses. Exposure levels are often higher than those found at today's work sites, and the possibility of using data for making reasonable, adequate extrapolations often remains unknown. Despite these limitations, it is the main intentions of the present text to inform and alert occupational health practitioners and other interested readers about what attempts have been made so far to gain knowledge about the situation in the vast majority of work sites, specifically, combined exposure to both at least one physical agent and one chemical agent. The presentation is ordered using the respective physical factors as subtitles under which published data concerning the particular factor's interaction with different chemicals are presented. Physical factors presented are mechanical factors such as sound waves (most often referred to as “noise”) and vibrations; the thermal factors heat and cold, electrostatic fields; and electromagnetic radiation from low frequency fields, radio frequencies, visible light, ultraviolet light, to ionizing radiation. Since many of these physical factors most naturally interacts with sensory functions, the text often focuses on interactions seen as sensory and nervous system alterations in both animals and humans. Exposures to physical factors and chemicals that are not primarily related to occupational exposure, for example, the multitude of drugs that can interact with sunlight, are considered as being a general toxicological problem rather than a specific occupational toxicological issue. Readers interested in such interactions are therefore referred to the pharmacological literature.