Probabilistic modeling of young children's overall lead exposure in France: integrated approach for various exposure media.
OBJECTIVE
Emissions of lead into the environment (and thus its environmental concentrations) have decreased in recent years. We sought to estimate the overall lead exposure of children aged 6 months to 6 years (the population group most exposed and most sensitive to lead) in France through the various media (air, food, water, soils, and dust) and the respective contributions of each medium to the total dose. We have focused on the general population, leaving aside specific risk factors such as deteriorated lead paints.


METHODS
We used the most recent French intake data for food and water, and a daily ingested quantity selected from the literature for soils and dust. Contamination data came from the first total diet study of contaminant levels in France (2000-2001), from regulatory testing of tap water (2004), a literature review of lead in urban soils, and a pilot study (2005) of lead in dust. Air quality monitoring measurements showed that the contribution of air could now be safely ignored. Weekly exposure doses were estimated with Monte Carlo simulations.


RESULTS
Median weekly exposure dose was 7.5 microg/kg bw.week for children aged 6 months to 3 years and 4.7 for those aged from 3-6 years. 95th percentiles were 13.5 and 8.7 microg/kg bw.week. Exposure came mainly from food. The principal uncertainties are associated with quantification limits in food and water, representativeness and traceability of tap water samples, and absence of recent data about urban soil contamination.


CONCLUSIONS
These results differ quite notably from earlier estimates and highlight the need, especially for policy-making purposes, to update exposure measurements for this metal.
Glorennec
Philippe
P
National School of Public Health, Avenue du Professeur Léon Bernard, 35043 Rennes Cédex, France. philippe.glorennec@ensp.fr
Bemrah
Nawel
N
Tard
Alexandra
A
Robin
Alban
A
Le Bot
Barbara
B
Bard
Denis
D
D000393:Air Pollutants / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D004391:Dust / Q000032:analysis; D004781:Environmental Exposure / Q000009:adverse effects; D004785:Environmental Pollutants / Q000032:analysis*; D005602:France; D006801:Humans; D007223:Infant; D007854:Lead / Q000032:analysis*; D007855:Lead Poisoning / Q000517:prevention & control; D015233:Models, Statistical; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis
D000393:Air Pollutants; D004391:Dust; D004785:Environmental Pollutants; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D007854:Lead