Morphological features of the microdistribution of naturally occurring ²¹⁰Pb/²¹⁰Po and ²²⁶Ra in the teeth of children and juveniles

Abstract

210Pb-supported 210Po activity on the outer enamel surface of permanent teeth constitutes an assay of cumulative environmental exposure with which to assess exposure in bone, both in utero and in childhood. Such assessment can be used to study geographical variations in the alpha-activity in teeth. More work is also required to determine the concentrations of both 210Po and 210Pb in the foetal skeleton.

Occurrence of 210 Po and Biological Effects of Low-Level Exposure: The Need for Research

“…Fetal 210 Pb is incorporated into bone and 210 Pb-supported 210 Po could irradiate hematopoietic stem cells in fetal marrow. 210 Po remains in place following decay of calcified 210 Pb (James et al 2004), and up to 80% of the marrow in lumbar vertebrae would be within range of alpha particles from 210 Po on bone surfaces because bone-marrow spaces are small in the fetus (Purnell et al 1999). Maternal 210 Po that passes the placenta, or 210 Pb-supported 210 Po in soft tissues, could migrate in the blood to the fetal liver or spleen and potentially expose hematopoietic stem cells.…”

“…210 Pb readily passes the placenta (Goyer 1990) and 210 Pb-supported 210 Po ( 210 Po originating from in situ decay of 210 Pb) can irradiate fetal tissues. 210 Po produced by decay of skeletal 210 Pb remains in the bone (James et al 2004); however, 210 Po from the decay of soft-tissue 210 Pb likely would follow typical 210 Po biokinetics. 210 Po activity begins to increase after 210 Pb ingestion and reaches 25% of the 210 Pb activity in 65 days, 50% in 145 days, and approximately 99% of the 210 Pb activity in 2 years.…”

Radionuclide exposure in animals and the public health implications

“…Po produced by the decay of skeletal 210 Pb remains in the bones, whereas 210 Po produced from soft tissue decay of 210 Pb follows typical 210 Po biokinetics (38). 210 Pb is a radionuclide that is known to have a high skeletal bioaccumulation and it will therefore not be surprising to find accumulation of 210 Po in the bones of exposed animals.…”

“…It was noted that concentrations of 226 Ra, 210 Po, and 210 Pb in bones were three orders of magnitude higher than concentrations found in the muscle, suggesting the affinity of these high-risk radionuclides for the skeletal system. Inferences from some reports point to the fact that Po biokinetics (38). 210 Pb is a radionuclide that is known to have a high skeletal bioaccumulation and it will therefore not be surprising to find accumulation of 210 Po in the bones of exposed animals.…”