Repeated bone lead levels in Queensland, Australia--previously a high lead environment.

Bone lead levels (finger and tibia) were measured, both in vivo and in vitro, with an x-ray fluorescence technique. In vivo finger-bone lead levels of 105 volunteers were estimated and subsequently re-estimated after a 5-y period. In many instances, elevated levels in some of these individuals probably resulted from lead ingested during childhood (i.e., more than 60 y ago). A decline in finger-bone lead from the initial value was accompanied by a mean finger-bone lead half-life of 6.2 y (n = 25); many individual's half-life values were less than 3.0 y. Perhaps one reason for these low values is the special propensity of finger bone to resorption during the involutional period, at which time there are high levels of circulating parathormone.