Arsenic has high affinity for which tissue, used for long-term exposure assessment?

• A. Keratin (nails, skin, hair)
• B. Adipose tissue
• C. Bone marrow
• D. Muscle tissue

Answer: (A)

Arsenic has a high affinity for keratin, so it becomes incorporated into keratin-rich tissues like nails, hair, and skin. This makes these tissues ideal for long-term exposure assessment because they reflect cumulative arsenic deposition over time as nails grow slowly and hair records arsenic along its length. Nails, in particular, provide a useful historical record over months. In contrast, adipose tissue stores are more for lipophilic substances, and bone marrow or muscle are not reliable repositories for chronic arsenic exposure.