Lead poisoning in livestock: primary storage site for lead is which tissue?

• A. Bone
• B. Blood
• C. Liver
• D. Muscle

Answer: (A)

Lead acts like calcium in the body and has a strong affinity for bone mineral, so the primary storage site is bone. During formation, lead is incorporated into the hydroxyapatite matrix of bone and remains there for long periods, effectively serving as a long-term reservoir. Blood lead levels mainly reflect recent exposure rather than total body burden, while liver and kidney handle metabolism and excretion, and muscle stores far less lead. Because bone holds most of the body’s lead, it’s the tissue that determines long-term burden and can release lead back into the circulation during periods of increased bone turnover, such as pregnancy or lactation.