title: Identification of sources of lead exposure in French children by lead isotope analysis: a cross-sectional study.
abstract: BACKGROUND
  The amount of lead in the environment has decreased significantly in recent years, and so did exposure. However, there is no known safe exposure level and, therefore, the exposure of children to lead, although low, remains a major public health issue. With the lower levels of exposure, it is becoming more difficult to identify lead sources and new approaches may be required for preventive action. This study assessed the usefulness of lead isotope ratios for identifying sources of lead using data from a nationwide sample of French children aged from six months to six years with blood lead levels ≥25 μg/L.
  
  
  METHODS
  Blood samples were taken from 125 children, representing about 600,000 French children; environmental samples were taken from their homes and personal information was collected. Lead isotope ratios were determined using quadrupole ICP-MS (inductively coupled plasma - mass spectrometry) and the isotopic signatures of potential sources of exposure were matched with those of blood in order to identify the most likely sources.
  
  
  RESULTS
  In addition to the interpretation of lead concentrations, lead isotope ratios were potentially of use for 57% of children aged from six months to six years with blood lead level ≥ 25 μg/L (7% of overall children in France, about 332,000 children), with at least one potential source of lead and sufficiently well discriminated lead isotope ratios. Lead isotope ratios revealed a single suspected source of exposure for 32% of the subjects and were able to eliminate at least one unlikely source of exposure for 30% of the children.
  
  
  CONCLUSIONS
  In France, lead isotope ratios could provide valuable additional information in about a third of routine environmental investigations.
authors.affiliation: EHESP - School of Public Health, Sorbonne Paris Cité, 35043 Rennes, France. youssef.oulhote@ehesp.fr
authors.forename: Youssef
authors.initials: Y
authors.lastname: Oulhote
authors.forename: Barbara
authors.initials: B
authors.lastname: Le Bot
authors.forename: Joel
authors.initials: J
authors.lastname: Poupon
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Lucas
authors.forename: Corinne
authors.initials: C
authors.lastname: Mandin
authors.forename: Anne
authors.initials: A
authors.lastname: Etchevers
authors.forename: Denis
authors.initials: D
authors.lastname: Zmirou-Navier
authors.forename: Philippe
authors.initials: P
authors.lastname: Glorennec
mesh_terms: D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004391:Dust / Q000032:analysis; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis* / Q000097:blood / Q000633:toxicity; D005602:France; D006798:Housing; D006801:Humans; D007223:Infant; D007554:Isotopes / Q000032:analysis / Q000097:blood / Q000633:toxicity; D007854:Lead / Q000032:analysis* / Q000097:blood / Q000633:toxicity*; D013058:Mass Spectrometry; D010150:Paint / Q000032:analysis; D012987:Soil / Q000032:analysis; D013054:Spectrophotometry, Atomic; D014881:Water Supply / Q000032:analysis
chemical_list: D004391:Dust; D004785:Environmental Pollutants; D007554:Isotopes; D012987:Soil; D007854:Lead