Tooth lead levels as an estimate of lead body burden in rats following pre- and neonatal exposure
Accurate assessment of early life lead exposure requires an accessible and reliable biomarker. Blood lead levels alone are not a suitable measure of chronic lead exposure, due to the rapid turnover and proportionally smaller amount compared to calcified tissues, such as bone and teeth. To further validate and standardise tooth lead levels as an appropriate biomarker of exposure, we designed a series of experiments where Wistar rats were fed, through drinking water, a regime of lead dosage that included stable, increasing and decreasing exposures, as well as prenatal exposure via the mother. At 15 days of age the animals were culled and blood, kidney, liver, brain, bone and teeth lead levels were assessed using inductively coupled plasma-mass spectrometry. Bone and tooth lead levels were by far the highest, and were reflective of the dosing parameters used. Brain lead levels were the lowest, suggesting that the blood–brain barrier provided some protection against lead uptake. These results give further support to the use of tooth lead levels as a biomarker of environmental lead exposure, particularly during early life periods.