Which substance is most readily absorbed through skin when pesticides are involved?

• A. Oil
• B. Water
• C. Wettable powder
• D. Formulation

Answer: (A)

The skin’s outer layer is rich in lipids, creating a lipid barrier. Substances that are soluble in fats (lipophilic) easily dissolve into these skin lipids and diffuse through to deeper tissues. Oil-based carriers in pesticide formulations blend with the skin’s lipids and carry the active ingredient across more readily than other forms. Water, being hydrophilic, does not penetrate this lipid-rich barrier as well, so absorption is limited. A wettable powder is a particulate form that must dissolve or be wetted before it can move through the skin, making absorption less efficient than an oil-based vehicle. Formulation can vary, but an oil-based carrier typically enhances dermal absorption more than water-based or dry forms, which is why oil is the best answer here.