Lead accumulation: Lead is primarily deposited into bone. What percentage of total lead is deposited into bone?

Lead accumulation: Lead is primarily deposited into bone. What percentage of total lead is deposited into bone?

• A. 94%
• B. 6%
• C. 50%
• D. 100%

Answer: (A)

Lead tends to accumulate in bone because it chemically resembles calcium and readily becomes incorporated into the bone mineral, hydroxyapatite. Since bone turnover is slow, most of the body's lead ends up stored there, creating a long-term reservoir. The vast majority of total body lead—about 90–95%, commonly cited as roughly 94%—is deposited in bone, with only a small fraction remaining in soft tissues and blood. This bone storage explains why lead exposure can have lasting effects and can be mobilized back into the bloodstream during periods of increased bone turnover. So the best answer is that approximately 94% of total lead is deposited into bone.

Lead tends to accumulate in bone because it chemically resembles calcium and readily becomes incorporated into the bone mineral, hydroxyapatite. Since bone turnover is slow, most of the body's lead ends up stored there, creating a long-term reservoir. The vast majority of total body lead—about 90–95%, commonly cited as roughly 94%—is deposited in bone, with only a small fraction remaining in soft tissues and blood. This bone storage explains why lead exposure can have lasting effects and can be mobilized back into the bloodstream during periods of increased bone turnover. So the best answer is that approximately 94% of total lead is deposited into bone.