<prompt> Half life of lead in bone is:1 year10 years20 yearsNone of the above  <response>: The half-life of lead compounds in the human body is, as a general rule, long, but it varies according to the tissue. Besides, it is almost impossible to determine its elimination rates, since the bones may have a large quantity ready to mobilize into the blood stream. Neveheless, some halflives are known for blood 3-4 weeks and bones 20-27 years. Ref: 