Which site on the human body absorbs the greatest percentage of a pesticide dose?

• A. Bottom of foot
• B. Scalp
• C. Forearm
• D. Hand

Answer: (B)

Dermal absorption varies by where on the body the chemical contacts the skin, because skin thickness, blood supply, and special pathways like hair follicles all influence how much pesticide can get into the body. The scalp stands out because its skin is relatively thin in many areas and it has a rich blood supply, plus a high density of hair follicles and sebaceous glands. These follicles and glands can act as entry routes and reservoirs, letting the pesticide penetrate more effectively and stay in contact longer, especially with relatively moist scalp conditions. In comparison, the bottom of the foot has very thick, tough skin with limited blood flow, and the forearm and hand typically have thicker, less permeable skin and fewer rapid-entry routes, which reduces absorption. So the scalp tends to absorb a larger portion of a pesticide dose due to its thinner skin, higher vascularity, and abundant hair follicles.