Sources of Environmental and Occupational Exposures

The route and site of exposure influence the effects of toxic chemicals on the body. In general, in the order of descending effectiveness and hazard, the routes for toxic agents are directly into the bloodstream, inhalation, intraperitoneal, subcutaneous, intramuscular, intradermal, oral, and dermal (Klaassen 1995, p. 15). This order would significantly differ for xenobiotics (substances that are foreign to the human body) that also have indirect health consequences, like radiological properties and genetic effects. 

Uranium is a naturally occurring element and is quite abundant in soil, seawater, fresh water sources, and plants as described in the previous chapters. Consequently, 

FIGURE 4.1 The main pathways for exposure to uranium compounds, the uptake and distribution routes, and the major excretion pathways. 

Ingestion of uranium contained in food and drinking water is the main route through which the general population is exposed to uranium compounds. The estimation of the average daily intake of uranium from food and drinking water based on several 

FIGURE 4.2 Biokinetic model for embedded fragments of depleted uranium. (From Leggett, R.W. and Pellmar, T.C., J. Environ. Radioact., 64, 205, 2003b. With permission.) 

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