Toxic agents Terms Links

Confusion often occurs with the use of the terms exposure , concentration , and dose . Dose is the amount of contaminant that is deposited or absorbed in the body of an exposed individual over a specific duration. Dose occurs as a result of exposure. Concentration is that level of contaminant present in the air potentially available to be inhaled. The atmospheric concentration of a chemical by itself does not define the total dose of a chemical delivered or the specific sites of potential injury. For a substance present in inhaled air to be toxic, a significant dose must first be removed from the inhaled air and be deposited on sensitive tissue. Knowledge of the dose to initial target sites provides a critical link between exposure and the subsequent biological response. Understanding the disposition of inhaled xenobiotics is complex and, due to space limitations, cannot be described in detail here. However, certain basic concepts need to be presented to provide information on the various factors related to exposure, dose, and response that are fundamental to understanding the potential human risk from inhaled chemical agents. 

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