Exposure synergistic effects

Several chemicals can act as initiators and/or promoting agents participating actively in the process of carcinogenesis and also producing synergistic effects when taken simultaneously via multiple routes of exposure. 

As the time of exposure to UV is increased, the magnitude of the synergistic effect between TMPTA and lithium nitrate is increased dramatically for the UV grafting of styrene to polypropylene (Table XI) such that after 16 hours of irradiation very large yields are obtained. Even with TFMA, the grafting yield in the 30% monomer solution is increased by almost one order of magnitude due to the synergistic effect. 

When two compounds exert the same action by acting at different sites, their interaction will often result in a synergistic effect but a simple additive effect is also a possibility (the synergism between smoking and asbestos exposure is the classical example). 

The authors concluded that the mixture induced effects on the liver and the kidney, and on the general metabolism at high doses but caused only minor effects on immune function, reproductive hormone levels, or general indices of reproductive function measures. The results suggested that additive or synergistic effects of exposure to contaminants resulting in residue levels representative of contemporary human tissue levels are unlikely to result in adverse effects on immune function or reproductive physiology in male rats. 

In reality, medical scientists cannot yet predict the toxic effects to individual humans from consuming low-level chemical mixtures that permeate our food. Although scientists know virtually nothing about the toxic effects of chemical mixtures, they do know that there can be synergistic effects from multiple chemical exposures.1... 

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