The apparent increase in the strength of the correlation between saliva lead and blood lead with increasing exposure, and the fact that this correlation is unaffected by age or smoking status, suggests that biological monitoring of salivary lead may be useful as a non-invasive surrogate for blood lead, but only at high exposure levels. The kinetics of lead within the body are complex and not yet entirely understood. Nriagu et al. (2006) found that the isotopic ratios (208Pb/206Pb and 207Pb/206Pb) were almost identical in blood and in saliva, suggesting that the lead content of saliva must be derived from that in the bloodstream. Brodeur et al. (1983) showed that blood and salivary lead respond differently

during and after lead exposure; moreover that salivary lead arises from the diffusible fraction in the blood plasma, and that it reflects much more recent Roxadustat nmr exposure than blood lead. Therefore saliva lead measurement may be useful in this context as a biomarker of recent lead exposure – for example as a screening tool for workers undergoing work such as demolition, which involves a risk of acute exposure. However, before saliva lead check details measurement could be utilised for the assessment of individuals; further work would need to be carried out to understand how saliva lead levels respond to exposure, and for how long after an exposure that the saliva lead levels

remain elevated. It may also be beneficial to obtain data on the variability of saliva lead measurements from the same worker, by studying multiple repeat samples in quick succession. The ICP-MS method proposed by this study allows sensitive determination of saliva lead with low detection limits and high recovery. The StatSure sampling device is currently effective for high occupational exposures, out but contamination from the device could confound measurements at lower environmental levels. The

correlation between saliva lead and blood lead was found to be stronger at higher levels of exposure. In an occupationally-exposed cohort, this correlation was not found to be significantly affected by age, smoking status or the history of the individual’s previous lead exposure. Further work could investigate the effects of these factors at lower environmental exposure levels. Despite its advantages as a non-invasive matrix, saliva lead measurement could only be useful as a surrogate for blood lead for highly-exposed populations. However, saliva lead may be useful in certain applications as an alternative biomarker for recent lead exposure. The authors declare that there are no conflicts of interest. Transparency Document. This publication and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.