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Source Identification Analysis of Lead in the Blood of Japanese Children by Stable Isotope Analysis
Mai Takagi1,2, Atsushi Tanaka2, Haruhiko Seyama2
1Department of Environmental Systems, University of Tokyo, Chiba 277-8563, Japan.
Insights
Lead exposure in Japanese children is low, but non-dietary sources like house dust and soil significantly contribute to blood lead levels. Minimizing exposure to these environmental factors is crucial for protecting children
Area of Science:
- Environmental Health
- Toxicology
- Pediatrics
Background:
- Lead (Pb) exposure negatively impacts children's neurodevelopment.
- Blood lead (BPb) concentrations in Japanese children are among the lowest globally.
- Identifying specific sources of lead exposure is essential for effective prevention strategies.
Purpose of the Study:
- To identify the sources of lead in the blood of Japanese children.
- To quantify the contribution of various environmental sources to blood lead levels.
Main Methods:
- Measured lead isotope ratios (PbIR) in whole blood from eight Japanese children using multi-collector ICP mass spectrometry.
- Analyzed lead isotope ratios in house dust, soil, duplicate diet, and tobacco samples from home environments.
- Employed linear programming to estimate the relative contributions of different sources to blood lead levels.
Main Results:
- Source apportionment was possible for three children, revealing contributions from diet (19-34%), soil (0-55%), and house dust (20-76%).
- Lead isotope ratios for the remaining five children indicated significant contributions from non-dietary sources.
- Non-dietary sources, including soil, house dust, and passive tobacco smoke, are important contributors to lead exposure.
Conclusions:
- Non-dietary sources play a substantial role in lead exposure among Japanese children, even with low overall blood lead levels.
- Environmental lead sources such as house dust and soil require attention for minimizing children's lead exposure.
- Lead isotope ratio analysis is a valuable tool for identifying lead exposure sources in pediatric populations.
Abstract:
Considering the negative effect of lead (Pb) on children's neurodevelopment, Pb exposure should be minimized to the lowest extent possible, though the blood Pb (BPb) concentrations in Japanese children are among the lowest in the world. To identify the sources of Pb in blood, isotope ratios (IRs: 207Pb/206Pb and 208Pb/206Pb) of Pb (PbIR) in whole blood from eight Japanese children were measured by multi-collector ICP mass spectrometry. Further, samples of house dust, soil, duplicate diet, and tobacco, collected from home environments, were also measured and were compared with PbIR of blood case by case. The relative contribution of Pb in the home environment to BPb were estimated by linear programming (finding an optimal solution which satisfy the combination of IRs and intakes from various sources) when appropriate. Source apportionment for three children could be estimated, and contributions of diet, soil, and house dust were 19-34%, 0-55%, and 20-76%, respectively. PbIR for the remaining five children also suggested that non-dietary sources also contributed to Pb exposure, though quantitative contributions could not be estimated. Non-dietary sources such as soil, house dust, and passive tobacco smoke are also important contributors to Pb exposure for Japanese children based on PbIR results.
