Long-term human exposure to lead from different media and intake pathways.
Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2μg/dl in children and almost 1μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented.
Pizzol
Massimo
M
Department of Policy Analysis, National Environmental Research Institute (NERI), Aarhus University, Denmark. mapi@dmu.dk
Thomsen
Marianne
M
Andersen
Mikael Skou
MS
D000328:Adult; D002675:Child, Preschool; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis / Q000097:blood*; D004787:Environmental Pollution / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007854:Lead / Q000032:analysis / Q000097:blood*; D008297:Male; D008962:Models, Theoretical
D004785:Environmental Pollutants; D007854:Lead