THE ROLE OF SKIN ABSORPTION AS A ROUTE OF EXPOSURE FOR VOLATILE ORGANIC COMPOUNDS
American Journal of Public Health, 1984, 74:479-484
COMPARED WITH ITS ABSORPTION THROUGH THE RESPIRATORY SYSTEM, SKIN ABSORPTION COULD BE THE MAJOR ROUTE OF PENETRATION INTO THE BODY. SKIN PENETRATION RATES HAVE BEEN FOUND TO BE REMARKABLY HIGH, AND THE OUTER LAYER OF SKIN IS A LESS EFFECTIVE BARRIER TO PENETRATION THAN TRADITIONALLY ASSUMED.
The more hydrated the skin, the greater the absorption. If the skin is hydrated (through perspiration or immersion in water) or if the contaminant compounds are in solution, diffusion and penetration will be enhanced.
Increased skin or water temperature will enhance skin absorption capacity proportionately. During swimming and bathing, it may be expected that greater hydration of skin surfaces will take place.
Any insult (i.e. sunburn) or injury (i.e. cuts, wounds, abrasions) to the outer layer of skin will lower its ability to act as a barrier against foreign substances. A history of skin disease such as psoriasis or eczema acts to lower the natural barrier of the outer skin layer, as do rashes, dermatitis, or any chronic skin condition.
Skin absorption rates vary with the different regions of the body. Underestimated is the case of whole body immersion during swimming or bathing. The epidermis of the hand represents a relatively greater barrier to penetration than many other parts of the body, including the scalp, forehead, abdomen, area in and around the ears, underarms, and the genital area. Penetrations through the genital area, in fact, is estimated to be 100% as compared to 8.6% for the forearm.
Other Routes of Entry
Other significant routes of absorption include oral, nasal, cheeks and mouth cavity, and eye and ear areas. These routes have been underestimated in their ability to absorb contaminants during immersion in water. Inhalation serves as yet another route. In the case of swimming or bathing, the volatized chemicals are likely to gather near the surface of the water and are readily inhalable. In addition, water may be swallowed in these situations.
Absorption rates obtained from healthy adults will again tend to underestimate absorption for children or populations that are more sensitive.
This information was compiled from the American Journal of Public Health