Which exposure route is illustrated by solvents penetrating the skin?

• A. Inhalation
• B. Ingestion
• C. Dermal absorption
• D. Subcutaneous injection

Answer: (C)

Exposure through the skin is dermal absorption. When a solvent comes into contact with the skin and moves through the skin’s outer barrier into the bloodstream, it represents dermal exposure leading to systemic absorption. Whether a solvent can do this depends on factors like how fat‑soluble it is, how long the skin is in contact with it, the dose, skin integrity, and temperature. The skin's stratum corneum is lipophilic, so solvents that dissolve into fats can cross more easily and reach circulation, potentially causing effects beyond the site of contact.

This particular scenario shows the solvent penetrating the skin rather than being inhaled into the lungs, swallowed into the GI tract, or delivered through a needle. Inhalation would involve vapors entering the respiratory system; ingestion would involve entry via the mouth and GI tract; subcutaneous injection would require introducing the chemical beneath the skin with a needle.