Drinking water uptake routes

To determine acceptable contaminant levels in soils, two primary exposure routes are usually considered (1) inlialation of gases, vapors, or airborne particulate emanating from the site, and (2) ingestion of contamimtted drinking water. Other routes that can contribute to e.xposure include absorption of pollutants tluough direct skin contact and uptake of wtiter or soil contantinants by plants that are part of the food chain. 

Biomagnification along terrestrial food chains is principally due to bioaccumulation from food, the principal source of most pollutants (Walker 1990b). In a few instances, the major route of uptake may be from air, from contact with contaminated surfaces, or from drinking water. The bioaccumulation factor (BAF) of a chemical is given by the following equation ... 

The most important uptake route for uranium is ingestion of food and drinking water, as shown in Table 26.1-2 (see Chapter 26.1, Section 26.1.7). The daily dietary intake of U for Ukrainian males is estimated at 7.8 mBq (Shiraishik et al. 1997), with typical daily intake values being 0.16 Bq for 0.0005 Bq for U, and 0.16 Bq for U. Military use of depleted uranium led to inhalation during combat and to shrapnel contamination (Bleise... 

Lead-containing environmental media ingestion or inhalation rates are presented here for ambient air, diverse human diets, drinking water, and dust and/or soil. Dermal contact and potential dermal uptake into the bloodstream for the inorganic forms of environmental Pb encountered by nonoccupational populations are very low compared to the other routes of exposure, and this route is not addressed. 

Larsen et al. [13] detected small amounts of PFOA (up to 140 ppb) in extracts of PTFE resins, obtained after applying pressure and increased temperatures to the material. Subsequent studies of cookware, coated with PTFE dispersions, have shown no detectable levels of PFOA extractable from cookware under normal use conditions [14]. A later study by the Norwegian Institute of Public Health (2007) went on further by detailing about these findings. In a worst case scenario the new study showed that an adult human would be exposed to 66 ng PFOA/kg bw, when drinking 100 ml water cooked in a PTFE coated pan. It was concluded that, even at an assumption of 100% uptake of PFOA, these extremely low levels will not be an essential intake route for humans. According to Horowitz, 98% of the PFOA intake is contributed to by food [15]. 

Human exposure mainly arises from combustion of fuels, plants, and waste, and consumption of adventitious cadmium present in food and water [83]. Humans and animals breathe cadmium-containing particles (mainly the oxide) and ingest cadmium complexes with their food and drinks. Cigarette smoking is a major route of uptake, whereas skin contact is not widespread owing to the natural dilution of cadmium, except for occupational settings. Dietary cadmium is more concentrated in some food items such as shellfish, offal, grains, and seeds. Some crops, such as rice, soybeans, or wheat, are more likely to accumulate cadmium firom polluted soils than others. 

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