Related Experiment Videos
Stable isotope identification of lead sources in preschool children--the Omaha Study
C R Angle1, W I Manton, K L Stanek
1University of Nebraska Medical Center, Omaha 68198-6055, USA.
Insights
Stable isotope analysis reveals hand-to-mouth behaviors significantly contribute to children's absorbed lead levels. Handwipe lead isotopic ratios predict blood and urinary lead, highlighting exposure pathways in former smelter cities.
Area of Science:
- Environmental Health
- Toxicology
- Analytical Chemistry
Background:
- Children living in former smelter cities face potential lead exposure.
- Understanding lead exposure sources is crucial for public health interventions.
Purpose of the Study:
- To determine the contribution of various sources (food, handdust, housedust, soil, air) to absorbed lead in children.
- To analyze stable lead isotopes to trace lead origins in children residing in a former smelter city.
Main Methods:
- A 12-month longitudinal study of 21 children (2-3 years old) in central Omaha.
- Monthly collection of duplicate diet, handwipe, and urine samples; quarterly blood lead samples.
- Analysis of lead isotopes (206Pb, 207Pb, 208Pb) using thermal ionization/mass spectrometry.
Main Results:
- Each child exhibited unique isotopic ratios for handwipe, blood, and urine lead.
- Handwipe lead isotopic ratios predicted 43% of the variance in blood and urine lead ratios.
- Blood and urine lead isotopic ratios were lower than handwipe and food, suggesting endogenous bone lead contribution.
Conclusions:
- Handwipe lead isotopic signatures are strong predictors of absorbed lead in children.
- Clean catch urine offers a non-invasive index for blood lead isotopic ratios in children.
- Findings emphasize the importance of hand-to-mouth behavior in lead exposure pathways for children.
Abstract:
The objective was to determine, from analysis of the naturally occurring stable isotopes of lead, the relative contribution of food, handdust, housedust, soil and air lead to the absorbed (urinary) lead and the blood lead of children living in a former smelter city. A longitudinal 12 month study was conducted of 21 children, 2 - 3 years of age, living in central Omaha, balanced for race, gender and socioeconomic status. Field clean samples were collected monthly of 24 hour duplicate diet, handwipe and urine, with quarterly blood lead, annual environmental lead, weekly air for total lead and 206Pb, 207Pb and 208Pb by thermal ionization/mass spectrometry with a 205Pb spike in a Class II laboratory. Despite residence in a smelter city each child had a unique isotopic ratio of handwipe, blood and urine lead, the latter being identical. There was no correlation of handwipe isotopic ratio with proximity to a lead emission source or to the decade of the housing stock. The isotopic ratio of the annual mean handwipe lead predicted 43% of the variance of the annual mean blood and urine lead ratio (r2 = .43; p = .001). Handwipe lead ratios correlated (p < or = .05) with those of the windowsills and air ducts. The mean isotopic ratios of blood and urine lead were lower than those of handwipe and food, consistent with a contribution by endogenous bone lead. Clean catch urine provides a noninvasive index of blood lead isotopic ratio in children, as in adults.